WO2005007687A1 - Compositions and methods for modulating ovarian follicular initiation - Google Patents

Abstract

The present invention provides methods for modulating ovarian follicular initiation, modulating fertility, treating infertility, and treating hormone-related diseases or disorders comprising modulating the expression or activity of FOXO3a. The present invention also provides an animal, e.g., transgenic mouse, in which the FOXO3a gene is misexpressed. Methods for identifying contraceptive agents are also described. Also described are methods for diagnosing premature ovarian failure (POF).

Description

COMPOSITIONS AND METHODS FOR MODULATING OVARIAN FOLLICULAR INITIATION

Related Applications This application claims the benefit of U.S. Provisional Application Serial No. 60/486,016, filed on July 9, 2003, the entire contents of which are incorporated herein by this reference.

Government Rights This invention was made at least in part with government support under grant no. K08-CA84044 awarded by the National Institutes of Health (NIH). The government has certain rights in this invention.

Background of the Invention The FOXO subfamily of forkhead transcription factors consists of Foxo3a (FKHRL1), Foxol (FKHR), and Foxo4 (AFX), all of which are downstream effectors of the PTEN/PI3K/AKT pathway, being directly phosphorylated and thereby inactivated (via retention in the cytoplasm) by the protein kinase AKT (Tran, H.,et al. 2003. Sci STKE 2003, RE5). Components of this pathway and the order of their interactions are highly conserved over large phylogenetic distances. In C. elegans, systematic genetic analyses have revealed the existence of a conserved insulin-like signalling pathway involved in development, longevity, and fertility (Ogg, S. and Ruvkun, G. 1998. Mol Cell 2:887 ; Paradis, S. and Ruvkun, G. 1998. Genes Dev 12,:2488 ; Dorman, J. B. , et al. 1995. Genetics 141 :1399). In mammals, the initiation of follicular growth is a regular, metered process ensuring that mature follicles are produced at each cycle. Once initiated, follicular growth is irreversible, and follicles recruited from the resting (primordial) follicle pool to the growing pool are destined to undergo apoptotic death (atresia) if not selected for further growth at subsequent stages of maturation (J. A. Elvin, M. M. Matzuk, Rev Reprod 3, 183 (1998)). Initiation of folliculogenesis is characterized morphologically by oocyte growth, followed by a transition of squamous to cuboidal GCs, GC proliferation, and formation of multiple GC layers (S. Lintern-Moore, G. P. Moore, Biol Reprod 20, 773 (1979)). Although the physiologic mechanisms that trigger growth initiation in a restricted number of follicles are unknown (J. A. Elvin, M. M. Matzuk, Rev Reprod 3, 183 (1998)) the primary mechanisms regulating the selection of follicules involves mechanisms intrinsic to the ovary, although circulating factors likely modulate the overall rate of initiation (J. E. Fortune, R. A. Cushman, C. M. Wahl, S. Kito, Molecular and Cellular Endocrinology 163, 53 (2000)). Follicular initiation is independent of pituitary gonadotropins as evidenced by the presence of growth initiation and atresia throughout infancy (H. Peters, A. G. Byskov, R. Himelstein-Braw, M. Faber, J Reprod Fertil 45, 559 (1975)), normal patterns of initiation in hypophysectomized animals and in the hypogonadal mouse mutant for the gonadotropin releasing hormone (GnΗR) (J. A. Elvin, M. M. Matzuk, Rev Reprod 3, 183 (1998)), and unaltered follicular initiation in sexually immature animals treated with high doses of gonadotropins (H. Peters, A. G. Byskov, S. Lintern-Moore, M. Faber, M. Andersen, J Reprod Fertil 35, 139 (1973)).

Summary of the Invention The present invention is based, at least in part, on the generation of animals bearing a null mutation in the Foxo3a gene, and the discovery that female animals bearing a null mutation in the Foxo3a gene exhibit a dramatic defect in follicular initiation. In particular, Foxo3a^~l~ females are born with a normal complement of oocytes, but experience follicular initiation within a few days of birth. This unrestricted recruitment of ovarian follicles leads to oocyte death, early depletion of functional ovarian follicles, and secondary infertility. Accordingly, it has been discovered that Foxo3a functions as a suppressor of ovarian follicular initiation. Accordingly, in one aspect, the present invention provides methods for modulating ovarian follicular initiation in a female subject comprising contacting FOXO3a or a cell expressing FOXO3a with a FOXO3a modulator, thereby modulating ovarian follicular initiation in a female subject. In one embodiment, the subject is a mammal. In another embodiment, the subject is a human. The FOXO3a modulator may function to either increase or decrease FOXO3a expression or activity. In one embodiment, the FOXO3a modulator increases FOXO3a expression or activity, thereby suppressing follicular initiation. In one embodiment of the invention, the FOXO3a modulator is used in contraception. In another embodiment, the FOXO3a modulator decreases FOXO3a expression or activity, thereby increasing follicular initiation, e.g., such that functional ovarian follicles are depleted. In one embodiment, follicular initiation is increased such that infertility occurs, e.g., such that functional ovarian follicles are depleted. Examples of FOXO3a inhibitors include small molecules, antisense FOXO3a nucleic acid molecules, ribozymes, FOXO3a siRNAs, and anti-FOXO3a antibodies. Examples of FOXO3a inducers include FOXO3a mimetics, e.g., peptidomimetics, small molecules, FOXO3a encoding nucleic acid molecules, and FOXO3a proteins or fragments thereof. In another embodiment, the FOXO3a modulator modulates c-Kit expression or activity. In still another embodiment, the FOXO3a modulator inhibits c- kit expression or activity. In yet another embodiment, the c-Kit inhibitor is imatinib mesylate (Gleevec^{I M}). In a further embodiment, the FOXO3a modulator modulates protein kinase AKT expression or activity. In another aspect, the invention provides methods for modulating fertility in a female subject comprising contacting FOXO3a or a cell expressing FOXO3a with a FOXO3a modulator, thereby modulating fertility in a female subject. In one embodiment, the expression or activity of FOXO3a is increased. In a related embodiment, the method is used in contraception. In another embodiment, the expression or activity of FOXO3a is decreased. In a related embodiment, the method causes infertility in said subject. In still another aspect, the invention provides methods for treating infertility in a female subject comprising administering to the female subject an effective amount of a FOXO3a antagonist or inhibitor such that follicular initiation is increased, thereby treating infertility in a female subject. In one embodiment, the FOXO3a antagonist is administered to the subject in combination with a gonadotropin, e.g., serially or concurrently. In one embodiment, the gonodotropin is follicle stimulating hormone (FSH) or leuteinizing hormone (LH), or a combination of both. In another embodiment, the FOXO3a antagonist is administered in an amount effective to increase follicular initiation without depleting functional ovarian follicles. In yet another aspect, the invention provides methods for treating a hormone-related disease or disorder in a subject comprising administering to the subject an effective amount of a FOXO3a antagonist, thereby treating a hormone-related disease or disorder in a subject. In one embodiment, the FOXO3a antagonist is administered in an amount effective to deplete functional ovarian follicles. In still another aspect, the invention provides a non-human animal, e.g., a mouse, in which the gene encoding the FOXO3a gene is misexpressed. In one embodiment, the animal is a transgenic animal. In another embodiment, the FOXO3a gene is disrupted by removal of DNA encoding all or part of the FOXO3a protein. In still another embodiment, the animal is homozygous for the disrupted gene. In a further embodiment, the animal is heterozygous for the disrupted gene. In still a further embodiment, the animal is a transgenic mouse with a transgenic disruption of the FOXO3a gene. For example, the disruption may be an insertion or a deletion. In another aspect, the invention provides methods for identifying a candidate compound useful as a contraceptive, comprising: contacting FOXO3a or a cell expressing FOXO3a with a test compound with a test compound; determining the activity or expression of FOXO3a in the presence of the test compound; selecting a compound that increases the activity or expression of FOXO3a; and identifying the selected compound as a candidate compound useful as a contraceptive. In still another aspect, the invention provides methods for identifying a candidate compound useful as a contraceptive comprising: contacting FOXO3a or a cell expressing FOXO3a with a test compound; and assaying for modulation of the expression or activity of FOXO3a in the presence of the test compound, wherein an increase of the expression or activity of FOXO3a by the test compound identifies the test compound as a candidate compound useful as a contraceptive. In yet another aspect, the invention provides methods for identifying a compound capable of modulating the expression or activity of FOXO3a comprising: contacting FOXO3a or a cell expressing FOXO3a with a test compound and determining the effect of the test compound on the expression or activity of FOXO3a in the presence of said test compound to thereby identify a compound which modulates the expression or activity of FOXO3a. In another aspect, the invention provides methods for predicting premature ovarian failure or a risk for premature ovarian failure in a subject comprising detecting the expression of the FOXO3a gene or the activity of FOXO3a in a cell or tissue of a subject, e.g., an ovarian cell or tissue, wherein a decrease in the expression of the FOXO3a gene or the activity of FOXO3a indicates premature ovarian failure or a risk for premature ovarian failure in a subject. The present invention also provides methods of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: obtaining a nucleic acid sample from the subject; and determining the identity of the nucleotide at nucleotide position 1,083 of SEQ ID NO:l, or the complement thereof, wherein the presence of at least one thymidine (T) allele at nucleotide position 1,083 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject. The present invention also provides methods of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: obtaining a nucleic acid sample from the subject; and determining the identity of the nucleotide at nucleotide position 1,343 of SEQ ID NO:l, or the complement thereof, wherein the presence of at least one thymidine (T) allele at nucleotide position 1,343 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject. Also included in the invention are methods of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: obtaining a nucleic acid sample from the subject; and determining the identity of the nucleotide at nucleotide position 1,945 of SEQ ID NO:l, or the complement thereof, wherein the presence of at least one adenine (A) allele at nucleotide position 1,945 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject. Furthermore, another aspect of the invention provides methods of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: obtaining a nucleic acid sample from the subject; and determining the identity of the nucleotide at nucleotide position 2,781 of SEQ ID NO:l, or the complement thereof, wherein the presence of at least one thymidine (T) allele at nucleotide position 2,781 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject. In one embodiment, determining comprises contacting a nucleic acid of the subject with at least one probe or primer which is capable of hybridizing to a FOXO3a gene. In another embodiment, the probe or primer is capable of specifically hybridizing to an allelic variant. In still another embodiment, the probe or primer has a nucleotide sequence from about 15 to about 30 nucleotides. In yet another embodiment, the probe or primer is a single stranded nucleic acid. In a further embodiment, determining is carried out by amplifying a portion of SEQ ID NO:l using the primers set forth as SEQ ID NO:3 and SEQ ID NO:4, or by amplifying a portion of SEQ ID NO:l using the primers set forth as SEQ ID NO: 5 and SEQ ID NO:6. In one embodiment, the probe or primer is labeled. In another embodiment, determining is carried out by allele specific hybridization. In still another embodiment, determining is carried out by primer specific extension. In a further embodiment, determining is carried out by an oligonucleotide ligation assay. In still another embodiment, determining is carried out by single-stranded conformation polymorphism. In a related aspect, the invention provides methods of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: obtaining a FOXO3a protein sample from the subject; and determining the identity of the amino acid at amino acid position 140 of SEQ ID NO:2, wherein the presence of Valine (Nal) at amino acid position 140 is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject as compared with a subject having Alanine (Ala) at this position. The invention also provides methods of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: obtaining a FOXO3a protein sample from the subject; and determining the identity of the amino acid at amino acid position 341 of SEQ ID ΝO:2, wherein the presence of Threonine (Thr) at amino acid position 341 is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject as compared with a subject having Alanine (Ala) at this position. Brief Description of the Drawings Figures 1A-E depict the targeting strategy and analysis of the disrupted Foxo3a gene. (A) Foxo3a genomic structure and recombinant alleles. The map shows exons 1 and 2 (the intron intervening exons 2 and 3 is 77 kb in size). Noncoding regions are indicated by hatchmarks and coding regions are shown in black (an asterisk marks the start codon). Primers used for PCR are indicated by small arrows. (B) Southern analysis of DNA from ES clones demonstrating targeting of the Foxo3a locus. DNA was digested with Nhel + Xhol (left panel) and Nhel + Hindlll (right panel). (C) PCR genotyping of wild-type and null alleles using primers a + b + d(Primer a: ATT CCT TTG GAA ATC AAC AAA ACT G (SEQ ID NO:7); primer b: TGC TTT GAT ACT ATT CCA CAA ACCC (SEQ ID NO:8); primer d: AGA TTT ATG TTC CCA CTT GCT TCCT (SEQ ID NO:9)). Sequencing of the 186 bp PCR product showed the expected sequences flanking the loxP site. (D) Northern analysis of total RNA (adult liver) showing deletion of major coding exon in Foxo3a transcript. (E) Northern analysis of total RNA from adult mouse tissues (mg, mammary gland; ut, uterus; ov, ovary; te, testis; 10%, mouse embryo fibroblasts under high serum; 0%, mouse embryo fibroblasts, serum starved for 24 hrs). The results of these analyses show that the Foxo3a gene was successfully disrupted. Figures 2A-B depict the phenotypic characterization oϊFoxo3 ^' mice.

(A) This panel shows that there is normal weight gain in Foxo3a^' females. Males also exhibited normal weight gain. (B) Continuous breeding assay starting at 6 weeks of age, showing cumulative number of progeny per female. These data show that although Foxo3a^' animals appear outwardly normal with normal sexual maturation, the smaller litter sizes observed in aging Foxo3ά'^~ females are consistent with oocyte deterioration and death evident by 8.5 weeks of age. Figures 3A-B depict the gross, and histologic analysis oϊFoxo3a^{~ '} and control ovaries. (A) This panel shows the size differences in Foxo3a^'/+ and Foxo3a^{~ '} ovaries, bar=l mm. (B) This panel depicts the histological analysis of Foxo3a^'/+ and Foxo3a^' ovaries at different ages, bar^~=100μ for all panels except at PD3, bar=^:20μ. Photographs are of sections stained with H&E except at 8.5 weeks and insets at 4.5 weeks (stained with PAS). For each time point, insets are at the same magnification. The results of these analyses show that there is a deregulation of follicular initiation resulting in global activation that occurs in Foxo3d ^' mice that eventually leads to follicular/oocyte atresia in all follicles that do not progress. Figures 4A-H depict the histomorphometric analyses of Foxo3 ^' and control ovaries. (A) Relative oocyte numbers at PD3. Numbers represent total counts of every 5^th section from serially sectioned ovaries (N=4 animals per genotype). (B) Relative primordial/primary follicle counts in aged females (48 weeks). Numbers represent total counts of every 10^th section from serially sectioned ovaries (N=3 animals per genotype). (C) (D) (E) Relative follicle counts at postnatal day 14, 4.5 weeks, and 8.5 weeks of age. Numbers represent the average number of each follicle type per section (N=3 animals per genotype). (F) Primordial oocyte diameters in Foxo3a^{+ +} and Foxo3a^' females at PD3, PD8, PD14 and 4.5 weeks of age. (G) Estimated volumes of newborn Foxo3a^+/+ (N=6), Foxo3a^'/+ (N=10), and Foxo3a^' (N=4) mouse ovaries grown in culture. (H) Primordial oocyte diameters in above Foxo3a^+/+,Foxo3a^{' +}, and Foxo3a^{~ '} ovaries after 8 days in culture. For all panels data is represented as mean values with error bars representing the SEM. P values are shown above the bars and were calculated by the exact t test. The results of these analyses show that Foxo3a functions within the ovary itself to suppress follicular initiation, and that circulating factors produced outside the ovary are not likely to have an essential role in the suppression of follicular initiation mediated by Foxo3a. Figures 5A-B depict the hormonal analyses of Foxo 3 a^'A and control animals. (A) Serum FSH and LH measurements of Foxo3α^+/+ (N=8), Foxo3α^'/+ (N=4) and Foxo3α^'A (N=12) females at 20 weeks of age. (B) Average number of released oocytes per female following superovulation (N=4 to 9 per genotype) at 3.0 and 4.5 weeks of age. For all panels data is represented as mean values + SEM. P values are shown above the bars and were calculated by the exact t test. These analyses show that the lack of Foxo3α function results in an intrinsic ovarian defect specifically involving follicular growth initiation, without impairing other aspects of follicular maturation or reproduction. Figure 6 is a box plot representation of oocyte diameter distributions in Foxo3α^+/+ and Foxo3 ^A ovaries at PD3 and PD8. Dashed lines represent the median. Solid lines represent the 25^th, 50^th, and 75^th percentiles, whiskers represent the 10^th and 90^th percentiles, and black circles represent the 5^th and 95^th percentiles. Approximately 50 oocytes were measured per group. Figures 7A-B depict the expression of FOX03α in human tissues as determined by Northern analysis. (A) Normal term gestation (brain, spleen, thymus, liver, ovary, and testis), lOμg of total RNA per lane. Top panel, human FOX03α cDNA probe; bottom panel, GAPDH loading control. (B) Adult tissues (peripheral blood leukocytes, colon wall, small intestine, ovary (pooled pre- and postmenopausal ovaries), testis, prostate, thymus, and spleen), 2μg of polyA+ RNA per lane. Top panel, human F0X03α cDNA probe; bottom panel, β-actin loading control. The results of these analyses show that FOX03α expression is readily detectable in human newborn and adult ovaries therefore may serve a conserved role in the regulation of follicular initiation in women. Figure 8 lists several polymoφhisms which were identified in the Foxo3a gene in DNA samples obtained from sixteen women known to be afflicted with premature ovarian failure (POF). Four polymoφhisms were identified, two in Exon 1 of the Foxo3a gene, and two in Exon 2 of the Foxo3a gene. Figures 9A-B depict the nucleotide (Figure 9A) and amino acid (Figure

9B) sequences of the human FOXO3a molecule (SEQ ID NOs:l and 2, respectively). The nucleotide sequence of FOXO3a is also described in GenBank Accession No. GI.-4503738 (SEQ ID NO:l) (the contents of which are included herein by reference).

Detailed Description of the Invention The present invention is based, at least in part, on the generation of animals bearing a null mutation in the Foxo3a gene, and the discovery that female animals bearing a null mutation in the Foxo3a gene exhibit a dramatic defect in follicular initiation. In particular, Foxo3a^~'^~ females are born with a normal complement of oocytes, but experience follicular initiation within a few days of birth. This unrestricted recruitment of ovarian follicles leads to oocyte death, early depletion of functional ovarian follicles, and secondary infertility. Accordingly, it has been discovered that Foxo3a functions as a suppressor of ovarian follicular initiation. Furthermore, while not intending to be bound by theory, it is believed that Foxo3a functions at the earliest stages of follicular growth to suppress follicular initiation.

Therefore, a functional connection has been shown between Foxo3a, preservation of the primordial follicle pool, and premature ovarian failure (POF), a common cause of infertility and premature aging in women. Accordingly, in one aspect, the invention features a non-human animal, in which the gene encoding the FOXO3a protein is misexpressed. In preferred embodiments the animal is a transgenic animal. The transgenic animal used in the methods of the invention can be, without limitation, a mammal; a bird; a reptile or an amphibian. Suitable mammals for uses described herein include: ruminants; ungulates; domesticated mammals; and dairy animals. Other suitable animals include: goats, sheep, camels, cows, pigs, horses, oxen, llamas, chickens, geese, and turkeys. Methods for the preparation and use of such animals are known in the art. A protocol for the production of a transgenic pig can be found in White and Yannoutsos, Current Topics in Complement Research: 64th Forum in Immunology, pp. 88-94; US Patent No. 5,523,226; US Patent No. 5,573,933; PCT Application WO93/25071; and PCT Application WO95/04744. A protocol for the production of a transgenic rat can be found in Bader and Ganten, Clinical and Experimental Pharmacology and Physiology, Supp. 3:S81-S87, 1996. A protocol for the production of a transgenic cow can be found in Transgenic Animal Technology, A Handbook, 1994, ed., Carl A. Pinkert, Academic Press, Inc. A protocol for the production of a transgenic sheep can be found in Transgenic Animal Technology, A Handbook, 1994, ed., Carl A. Pinkert, Academic Press, Inc. In another aspect, the present invention provides methods for modulating ovarian follicular initiation in a subject by administering a FOXO3a modulator to either induce or inhibit FOXO3a expression or activity. The present invention also provides methods for modulating fertility in a subject by administering a FOXO3a modulator to either induce or inhibit FOXO3a expression or activity. In one embodiment, FOXO3a expression or activity is increased by administering an inducer or agonist of FOXO3a expression or activity, thereby increasing suppression of ovarian follicular initiation. In this embodiment, the FOXO3a inducer or agonist may be used as a contraceptive as follicular initiation is delayed, while the follicular reserve pool is preserved until the time that fertility is desired. In an alternative embodiment, FOXO3a expression or activity is reduced or inhibited by administering an inhibitor or antagonist of FOXO3a expression or activity, thereby increasing ovarian follicular initiation. This increase in follicular initiation may lead to complete depletion of functional ovarian follicles, resulting in infertility in the subject. This embodiment is useful in situations where sterility is desired. For example, depletion of functional ovarian follicles leading to sterility may be useful as an alternative to surgical sterilization in humans, e.g., females, to control animal populations, or to treat hormone-related diseases or disorders, e.g., hormone- dependent tumors or migraine headaches. In a related embodiment, an inhibitor or antagonist of FOXO3a expression or activity may be used to treat infertility in a subject. In this embodiment, an inhibitor or antagonist of FOXO3a expression or activity is administered to a subject in an amount or dosage sufficient to increase follicular initiation, leading to superovulation, without completely depleting functional ovarian follicles, thereby treating infertility in a subject. Gonodotropins, e.g., leutinizing hormone (LH) or follicular stimulating hormone (FSH), may be administered in combination with the FOXO3a inhibitor, e.g., either sequentially or concurrently to increase follicular genesis, thereby further treating infertility. Administering a FOXO3a inhibitor or antagonist may also be useful in the procurement of eggs from laboratory animals following superovulation caused by the administration of the FOXO3a antagonist. In another aspect, the invention features methods for identifying a compound which modulates the expression or activity of FOXO3a. The methods include contacting FOXO3a or a cell expressing FOXO3a with a test compound and determining the effect of the test compound on the expression or activity of FOXO3a to, thereby, identify a compound which modulates, e.g., increases or decreases, FOXO3a expression or activity. The present invention is also based, at least in part, on the identification of polymoφhic regions within Foxo3a which are associated with POF. Four single nucleotide polymoφhisms (SNPs) were identified from DNA samples isolated from subjects with POF (see Figure 8). Accordingly, SNPs in the Foxo3a gene, as well as other SNPs in linkage disequilibrium with the SNPs identified herein, can be utilized to diagnose, in a subject, POF or the risk of developing POF. In particular, a subject having POF or at risk for developing POF may be identified by determining whether the subject has a specific allele listed in Figure 8. For example, the polymoφhisms included in the invention include SNPs at nucleotide positions 1,083, 1,343, 1,945, and 2,781 of the FOXO3a nucleotide sequence (set forth herein as SEQ ID NO:l). The polymoφhisms at nucleotide positions 1,083 and 2,781 of SEQ ID NO:l are silent polymoφhisms which do not result in any amino acid change in the FOXO3a protein. The polymoφhisms at nucleotide positions 1,343 and 1,945 result in changes in the FOXO3a protein at amino acid residues 140 and 341, respectively. Accordingly, the presence of at least one thymidine (T) allele at nucleotide position 1,083 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject; the presence of at least one thymidine (T) allele at nucleotide position 1,343 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject; the presence of at least one adenine (A) allele at nucleotide position 1,945 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject; and the presence of at least one thymidine (T) allele at nucleotide position 2,781 of SEQ ID NO. l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject. The SNPs identified herein may be identified using any known method of identification, including use of the primers identified herein as SEQ ID NOs:3 and 4 for amplification of Exon 1, and the primers identified herein as SEQ ID NOs:5 and 6 for amplification of Exon 2. In order for a subject to be diagnosed with POF, or at risk for POF, the subject may have one or both polymoφhic alleles at the specified polymoφhic position. A subject having a single polymoφhic allele at the polymoφhic site, e.g., a subject having a T and a cytidine (C) at nucleotide position 1,343 of SEQ ID NO: 1, would result in POF over the lifetime of the subject. The presence of both mutant alleles are not necessary to result in POF. In a related aspect, the invention provides methods of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: obtaining a FOXO3a protein sample from the subject; and determining the identity of the amino acid at amino acid position 140 of SEQ ID NO:2, wherein the presence of Valine (Val) at amino acid position 140 is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject as compared with a subject having Alanine (Ala) at this position. Furthermore, the presence of Threonine (Thr) at amino acid position 341 is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject as compared with a subject having Alanine (Ala) at this position. In another aspect, the invention provides a subject having POF, or at risk for developing POF, may also be identified by determining decreased expression or activity of FOXO3a in a tissue, e.g., ovarian tissue.

Definitions As used herein, the term "modulator of FOXO3a expression or activity" includes a compound or agent that is capable of modulating or regulating FOXO3a expression or at least one FOXO3a activity, as described herein. A modulator of FOXO3a expression or activity can be an inducer of FOXO3a expression or activity or an inhibitor of FOXO3a expression or activity. As used herein, an "inducer or agonist of FOXO3a activity" agonizes, stimulates, enhances, and/or mimics a FOXO3a activity, either completely or partially. An "inducer or agonist of FOXO3a expression" increases, enhances, or stimulates FOXO3a expression, either completely or partially. As used herein, an "inhibitor or antagonist of FOXO3a activity" antagonizes, reduces, or blocks a FOXO3a activity, either completely or partially. An "inhibitor or antagonist of FOXO3a expression" reduces or blocks FOXO3a expression, either completely or partially. Examples of FOXO3a inhibitors include small molecules, antisense FOXO3a nucleic acid molecules, ribozymes, FOXO3a siRNAs, and anti-FOXO3a antibodies. Examples of FOXO3a inducers include FOXO3a mimetics, e.g., peptidomimetics, small molecules, nucleic acid molecules encoding FOXO3a, and FOXO3a proteins or fragments thereof. Foxo3a is a downstream effector of the PTEN/PI3K/AKT pathway, and is directly phosphorylated and thereby inactivated (via retention in the cytoplasm) by the protein kinase AKT (Tran, H., et al. (2003) Sci STKE 2003, RE5). Accordingly, FOXO3a modulators also include modulators of upstream or downstream molecules in the protein kinase AKT pathway. For example, modulators of expression or activity of protein kinase AKT or expression or activity of Kit-c, e.g., imatinib mesylate (Gleevec™) are included herein as modulators of FOXO3a.

As used interchangeably herein, a "FOXO3a activity", "biological activity of FOXO3a" or "functional activity of FOXO3a" refers to an activity exerted by a FOXO3a polypeptide or nucleic acid molecule on a FOXO3a responsive molecule, cell, or tissue, as determined in vitro and in vivo, according to standard techniques. In an exemplary embodiment, a FOXO3a activity is the ability suppress, delay, or inhibit ovarian follicular initiation. In another embodiment, a FOXO3a activity is the ability to modulate fertility. In yet another embodiment, a FOXO3a activity is the ability to activate or repress genes downstream from foxo3a. The term "treatment", as used herein, is defined as the application or administration of a therapeutic agent to a patient, or application or administration of a therapeutic agent to an isolated tissue or cell line from a patient, who has a disease or disorder, a symptom of a disease or disorder or a predisposition toward a disease or disorder, with the puφose of curing, healing, alleviating, relieving, altering, remedying, ameliorating, improving or affecting the disease or disorder, the symptoms of disease or disorder or the predisposition toward a disease or disorder. A therapeutic agent includes, but is not limited to, small molecules, peptides, peptidomimetics, antibodies, ribozymes, siRNAs, and sense and antisense oligonucleotides described herein. As used herein, "follicular initiation" or "ovarian follicular initiation," "follicular activation" or "ovarian follicular activation" includes the process by which primordial ovarian follicles are selected for growth and maturation. As used herein, "administering a treatment to an animal or cell" is intended to refer to dispensing, delivering or applying a treatment to an animal or cell. In terms of the therapeutic agent, the term "administering" is intended to refer to contacting or dispensing, delivering or applying the therapeutic agent to an animal by any suitable route for delivery of the therapeutic agent to the desired location in the animal, including delivery by either the parenteral or oral route, intramuscular injection, subcutaneous/intradermal injection, intravenous injection, buccal administration, transdermal delivery and administration by the intranasal or respiratory tract route. As used herein, the term "compound" includes any agent, e.g., peptide, peptidomimetic, small molecule, or other drug, which binds to FOXO3 a proteins or has a stimulatory or inhibitory effect on, for example, FOXO3a expression or FOXO3a activity. As used herein, the term "contraception" includes the prevention of fertilization, e.g., of a female subject, preferably without destroying fertility by, e.g., depleting functional ovarian follicles. The term "polymoφhism" refers to the coexistence of more than one form of a gene or portion thereof. A portion of a gene of which there are at least two different forms, i.e., two different nucleotide sequences, is referred to as a "polymoφhic region of a gene." A polymoφhic locus can be a single nucleotide, the identity of which differs in the other alleles. A polymoφhic locus can also be more than one nucleotide long. The allelic form occurring most frequently in a selected population is often referred to as the reference and/or wildtype form. Other allelic forms are typically designated or alternative or variant alleles. Diploid organisms may be homozygous or heterozygous for allelic forms. A diallelic or biallelic polymoφhism has two forms. A trialleleic polymoφhism has three forms. The term "single nucleotide polymoφhism" (SNP) refers to a polymoφhic site occupied by a single nucleotide, which is the site of variation between allelic sequences. A SNP usually arises due to substitution of one nucleotide for another at the polymoφhic site. SNPs can also arise from a deletion of a nucleotide or an insertion of a nucleotide relative to a reference allele. Typically the polymoφhic site is occupied by a base other than the reference base. For example, where the reference allele contains the base "T" (thymidine) at the polymoφhic site, the altered allele can contain a "C" (cytidine), "G" (guanine), or "A" (adenine) at the polymoφhic site. SNP's may occur in protein-coding nucleic acid sequences, in which case they may give rise to a defective or otherwise variant protein, or genetic disease. Such a SNP may alter the coding sequence of the gene and therefore specify another amino acid (a "missense" SNP) or a SNP may introduce a stop codon (a "nonsense" SNP). When a SNP does not alter the amino acid sequence of a protein, the SNP is called "silent." SNP's may also occur in noncoding regions of the nucleotide sequence. This may result in defective protein expression, e.g., as a result of alternative spicing, or it may have no effect. The term "linkage" describes the tendency of genes, alleles, loci or genetic markers to be inherited together as a result of their location on the same chromosome. It can be measured by percent recombination between the two genes, alleles, loci, or genetic markers. The term "linkage disequilibrium," also referred to herein as "LD," refers to a greater than random association between specific alleles at two marker loci within a particular population. In general, linkage disequilibrium decreases with an increase in physical distance. If linkage disequilibrium exists between two markers, or SNPs, then the genotypic information at one marker, or SNP, can be used to make probabilistic predictions about the genotype of the second marker. As used herein, a "transgenic animal" includes an animal, e.g., a non- human mammal, e.g., a swine, a monkey, a goat, or a rodent, e.g., a mouse, in which one or more, and preferably essentially all, of the cells of the animal include a transgene. The transgene is introduced into the cell, directly or indirectly by introduction into a precursor of the cell, e.g., by microinjection, transfection or infection, e.g., by infection with a recombinant virus. The term genetic manipulation includes the introduction of a recombinant DNA molecule. This molecule may be integrated within a chromosome, or it may be extrachromosomally replicating DNA. As used herein, the term "rodent" refers to all members of the phylogenetic order Rodentia. As used herein, the term "misexpression" includes a non-wild type pattern of gene expression. Expression as used herein includes transcriptional, post transcriptional, e.g., mRNA stability, translational, and post translational stages. Misexpression includes: expression at non-wild type levels, i.e., over or under expression; a pattern of expression that differs from wild type in terms of the time or stage at which the gene is expressed, e.g., increased or decreased expression (as compared with wild type) at a predetermined developmental period or stage; a pattern of expression that differs from wild type in terms of decreased expression (as compared with wild type) in a predetermined cell type or tissue type; a pattern of expression that differs from wild type in terms of the splicing size, amino acid sequence, post- transitional modification, or biological activity of the expressed polypeptide; a pattern of expression that differs from wild type in terms of the effect of an environmental stimulus or extracellular stimulus on expression of the gene, e.g., a pattern of increased or decreased expression (as compared with wild type) in the presence of an increase or decrease in the strength of the stimulus. Misexpression includes any expression from a transgenic nucleic acid. Misexpression includes the lack or non-expression of a gene or transgene, e.g., that can be induced by a deletion of all or part of the gene or its control sequences. As used herein, the term "knockout" refers to an animal or cell therefrom, in which the insertion of a transgene disrupts an endogenous gene in the animal or cell therefrom. This disruption can essentially eliminate FOXO3a in the animal or cell. In preferred embodiments, misexpression of the gene encoding the FOXO3a protein is caused by disruption of the FOXO3a gene. For example, the FOXO3a gene can be disrupted through removal of DNA encoding all or part of the protein. In preferred embodiments, the animal can be heterozygous or homozygous for a misexpressed FOXO3a gene, e.g., it can be a transgenic animal heterozygous or homozygous for a FOXO3a transgene. In preferred embodiments, the animal is a transgenic mouse with a transgenic disruption of the FOXO3a gene, preferably an insertion or deletion, which inactivates the gene product. In another aspect, the invention features, a nucleic acid molecule which, when introduced into an animal or cell, results in the misexpression of the FOXO3a gene in the animal or cell. In preferred embodiments, the nucleic acid molecule, includes an

FOXO3a nucleotide sequence which includes a disruption, e.g., an insertion or deletion and preferably the insertion of a marker sequence. The nucleotide sequence of the wild type FOXO3a is known in the art and described in, for example, Anderson, et al (1998) Genomics 47, 187-199, the contents of which are incoφorated herein by reference. As used herein, the term "marker sequence" refers to a nucleic acid molecule that (a) is used as part of a nucleic acid construct (e.g., the targeting construct) to disrupt the expression of the gene of interest (e.g., the FOXO3a gene) and (b) is used to identify those cells that have incoφorated the targeting construct into their genome. For example, the marker sequence can be a sequence encoding a protein which confers a detectable trait on the cell, such as an antibiotic resistance gene, e.g., neomycin resistance gene, or an assayable enzyme not typically found in the cell, e.g., alkaline phosphatase, horseradish peroxidase, luciferase, beta-galactosidase and the like. As used herein, "disruption of a gene" refers to a change in the gene sequence, e.g., a change in the coding region. Disruption includes: insertions, deletions, point mutations, and rearrangements, e.g., inversions. The disruption can occur in a region of the native FOXO3a DNA sequence (e.g., one or more exons) and/or the promoter region of the gene so as to decrease or prevent expression of the gene in a cell as compared to the wild-type or naturally occurring sequence of the gene. The "disruption" can be induced by classical random mutation or by site directed methods. Disruptions can be transgenically introduced. The deletion of an entire gene is a disruption. Preferred disruptions reduce FOXO3a levels to about 50% of wild type, in heterozygotes or essentially eliminate FOXO3a in homozygotes. As used herein, the term "transgenic cell" refers to a cell containing a transgene. Various aspects of the invention are described in further detail in the following subsections:

I. Screening Assays: The invention provides a method (also referred to herein as a "screening assay") for identifying modulators, i.e., candidate or test compounds or agents (e.g., peptides, peptidomimetics, small molecules (organic or inorganic) or other drugs) which bind to FOXO3a proteins, have a stimulatory or inhibitory effect on, for example,

FOXO3a expression or FOXO3a activity, or have a stimulatory or inhibitory effect on, for example, the expression or activity of a FOXO3a substrate. Compounds identified using the assays described herein may be useful for modulating ovarian follicular initiation, modulating fertility, e.g., by causing increased fertility or decreased fertility (e.g., for use as a contraceptive), treating infertility, or for treating hormone-related diseases or disorders. These assays are designed to identify compounds that bind to or interact with a FOXO3a protein, or bind to or interact with other intracellular or extracellular proteins that interact with or modulate a FOXO3a protein. Such compounds may include, but are not limited to peptides, antibodies, nucleic acid molecules, siRNAs, or small organic or inorganic compounds. Such compounds may also include other cellular proteins. Compounds identified via assays such as those described herein may be useful, for example, modulating ovarian follicular initiation, modulating fertility, e.g., by causing increased fertility or decreased fertility (e.g., for use as a contraceptive), treating infertility, or for treating hormone-related diseases or disorders. In instances whereby increased FOXO3a activity or expression is desired, e.g., for contraception, compounds that interact with the FO O3a protein may include compounds which accentuate or amplify the expression or activity of FOXO3a protein. Such compounds would bring about an effective increase in the level of FOXO3a protein activity, thus acting as a contraceptive through suppression of follicular initiation. Alternatively, in instances whereby decreased FOXO3a activity or expression is desired, e.g., to result in superovulation as a treatment for infertility or as an inducer of sterility through complete depletion of functional ovarian follicles, compounds that interact with the FOXO3a protein may include compounds which inhibit or suppress the expression or activity of FOXO3a protein. Such compounds would bring about an effective decrease in the level of FOX O3a protein activity, thus acting as a treatment for infertility or an inducer of sterility, depending on the dosage of the compound and the length of time the compound is administered. For example, a partial antagonist or an antagonist administered in a dosage or for a length of time to increase ovulation without depletion of functional ovarian follicles, would act to increase fertility in a subject, thereby treating infertility. In one embodiment, the invention provides assays for screening candidate or test compounds which are substrates of or interact with a FOXO3a protein or polypeptide or biologically active portion thereof. In another embodiment, the invention provides assays for screening candidate or test compounds which bind to or modulate the activity of a FOXO3a protein or polypeptide or biologically active portion thereof. The test compounds of the present invention can be obtained using any of the numerous approaches in combinatorial library methods known in the art, including: biological libraries; spatially addressable parallel solid phase or solution phase libraries; synthetic library methods requiring deconvolution; the 'one-bead one-compound' library method; and synthetic library methods using affinity chromatography selection. The biological library approach is limited to peptide libraries, while the other four approaches are applicable to peptide, non-peptide oligomer or small molecule libraries of compounds (Lam, K.S. (1991) Anticancer Drug Des. 12:145). Examples of methods for the synthesis of molecular libraries can be found in the art, for example in: DeWitt et al. (1993) Proc. Natl Acad. Sci. U.S.A. 90:6909; Erb et al. (1994) Proc. Natl. Acad. Sci. USA 91:11422; Zuckermann et al. (1994). J. Med. Chem. 37:2678; Cho et al. (1993) Science 261 :1303; Carrell et al. (1994) Angew. Chem. Int. Ed. Engl. 33:2059; Carell et al. (1994) Angew. Chem. Int. Ed. Engl. 33:2061; and in Gallop et al. (1994) J. Med. Chem. 37:1233. Libraries of compounds may be presented in solution (e.g., Houghten

(1992) Biotechniques 13:412-421), or on beads (Lam (1991) Nature 354:82-84), chips (Fodor (1993) Nature 364:555-556), bacteria (Ladner USP 5,223,409), spores (Ladner USP '409), plasmids (Cull et al. (1992) Proc Natl Acad Sci USA 89:1865-1869) or on phage (Scott and Smith (1990) Science 249:386-390); (Devlin (1990) Science 249:404- 406); (Cwirla et al. (1990) Proc. Natl. Acad. Sci. 87:6378-6382); (Felici (1991) J. Mol. Biol. 222:301-310); (Ladner supra.). In one embodiment, an assay is a cell-based assay in which a cell which expresses a FOXO3a protein or biologically active portion thereof is contacted with a test compound and the ability of the test compound to modulate FOXO3a activity is determined. Determining the ability of the test compound to modulate FOXO3a activity can be accomplished by monitoring, for example, intracellular calcium, IP , cAMP, or diacylglycerol concentration, or the phosphorylation profile of intracellular proteins, or the level of transcription of downstream genes. The cell can be of mammalian origin, e.g., an ovarian cell. In one embodiment, compounds that interact with FOXO3a binding site can be screened for their ability to function as ligands, i.e., to bind to FOXO3a binding site and modulate transcription or modulate a signal transduction pathway. Identification of FOXO3a ligands, and measuring the activity of the ligand- FOXO3a complex, leads to the identification of modulators (e.g., antagonists or agonists) of this interaction. Such modulators may be useful in the modulation of ovarian follicular initiation, fertility, e.g., by causing increased fertility or decreased fertility (e.g., for use as a contraceptive), treatment of infertility through depletion of functional ovarian follicles, or in the treatment of hormone-related diseases or disorders. The ability of the test compound to modulate FOXO3a binding to a substrate or to bind to FOXO3a can also be determined. Determining the ability of the test compound to modulate FOXO3a binding to a substrate can be accomplished, for example, by coupling the FOXO3a substrate with a radioisotope or enzymatic label such that binding of the FOXO3a substrate to FOXO3a can be determined by detecting the labeled FOXO3a substrate in a complex. FOXO3a could also be coupled with a radioisotope or enzymatic label to monitor the ability of a test compound to modulate FOXO3a binding to a FOXO3a substrate in a complex. Determining the ability of the test compound to bind FOXO3a can be accomplished, for example, by coupling the compound with a radioisotope or enzymatic label such that binding of the compound to FOXO3a can be determined by detecting the labeled FOXO3a compound in a complex. For example, compounds (e.g., FOXO3a ligands or substrates) can be labeled with 125^ 35s, 14c, or ^H, either directly or indirectly, and the radioisotope detected by direct counting of radioemmission or by scintillation counting. Compounds can further be enzymatically labeled with, for example, horseradish peroxidase, alkaline phosphatase, or luciferase, and the enzymatic label detected by determination of conversion of an appropriate substrate to product. It is also within the scope of this invention to determine the ability of a compound (e.g., a FOXO3a ligand or substrate) to interact with FOXO3a without the labeling of any of the interactants. For example, a microphysiometer can be used to detect the interaction of a compound with FOXO3a without the labeling of either the compound or the FOXO3a (McConnell, H. M. et al (1992) Science 257:1906-1912. As used herein, a "microphysiometer" (e.g., Cytosensor) is an analytical instrument that measures the rate at which a cell acidifies its environment using a light-addressable potentiometric sensor (LAPS). Changes in this acidification rate can be used as an indicator of the interaction between a compound and FOXO3a. In another embodiment, an assay is a cell-based assay comprising contacting a cell expressing a FOXO3a target molecule (e.g., a FOXO3a substrate) with a test compound and determining the ability of the test compound to modulate (e.g., stimulate or inhibit) the activity of the FOXO3a target molecule. Determining the ability of the test compound to modulate the activity of a FOXO3a target molecule can be accomplished, for example, by determining the ability of the FOXO3a protein to bind to or interact with the FOXO3a target molecule. Determining the ability of the FOXO3a protein or a biologically active fragment thereof, to bind to or interact with a FOXO3a target molecule can be accomplished by one of the methods described above for determining direct binding. In a preferred embodiment, determining the ability of the FOXO3a protein to bind to or interact with a FOXO3a target molecule can be accomplished by determining the activity of the target molecule. For example, the activity of the target molecule can be determined by detecting induction of a cellular second messenger of the target (i.e., 2+ intracellular Ca , diacylglycerol, IP₃, cAMP), detecting catalytic/enzymatic activity of the target on an appropriate substrate, detecting the induction of a reporter gene (comprising a target-responsive regulatory element operatively linked to a nucleic acid encoding a detectable marker, e.g., luciferase), or detecting a target-regulated cellular response (e.g., gene expression). In yet another embodiment, an assay of the present invention is a cell-free assay in which a FOXO3a protein or biologically active portion thereof, is contacted with a test compound and the ability of the test compound to bind to the FOXO3a protein or biologically active portion thereof is determined. Preferred biologically active portions of the FOXO3a proteins to be used in assays of the present invention include fragments which participate in interactions with non-FOXO3a molecules, e.g., fragments with high surface probability scores. Binding of the test compound to the FOXO3a protein can be determined either directly or indirectly as described above. In a preferred embodiment, the assay includes contacting the FOXO3a protein or biologically active portion thereof with a known compound which binds FOXO3a to form an assay mixture, contacting the assay mixture with a test compound, and determining the ability of the test compound to interact with a FOXO3a protein, wherein determining the ability of the test compound to interact with a FOXO3a protein comprises determining the ability of the test compound to preferentially bind to FOXO3a or biologically active portion thereof as compared to the known compound. Compounds that modulate the interaction of FOXO3a with a known target protein may be useful in regulating the activity of a FOXO3a protein, especially a mutant FOXO3a protein. In another embodiment, the assay is a cell-free assay in which a FOXO3a protein or biologically active portion thereof is contacted with a test compound and the ability of the test compound to modulate (e.g., stimulate or inhibit) the activity of the FOXO3a protein or biologically active portion thereof is determined. Determining the ability of the test compound to modulate the activity of a FOXO3a protein can be accomplished, for example, by determining the ability of the FOXO3a protein to bind to a FOXO3a target molecule by one of the methods described above for determining direct binding. Determining the ability of the FOXO3a protein to bind to a FOXO3a target molecule can also be accomplished using a technology such as real-time Biomolecular Interaction Analysis (BIA) (Sjolander, S. and Urbaniczky, C. (1991) Anal. Chem. 63:2338-2345 and Szabo et al (1995) Curr. Opin. Struct. Biol. 5:699-705). As used herein, "BIA" is a technology for studying biospecific interactions in real time, without labeling any of the interactants (e.g., BIAcore). Changes in the optical phenomenon of surface plasmon resonance (SPR) can be used as an indication of realtime reactions between biological molecules. In another embodiment, determining the ability of the test compound to modulate the activity of a FOXO3a protein can be accomplished by determining the ability of the FOXO3a protein to further modulate the activity of a downstream effector of a FOXO3a target molecule. For example, the activity of the effector molecule on an appropriate target can be determined or the binding of the effector to an appropriate target can be determined as previously described. In yet another embodiment, the cell-free assay involves contacting a

FOXO3a protein or biologically active portion thereof with a known compound which binds the FOXO3a protein to form an assay mixture, contacting the assay mixture with a test compound, and determining the ability of the test compound to interact with the FOXO3a protein, wherein determining the ability of the test compound to interact with the FOXO3a protein comprises determining the ability of the FOXO3a protein to preferentially bind to or modulate the activity of a FOXO3a target molecule. In more than one embodiment of the above assay methods of the present invention, it may be desirable to immobilize either FOXO3a or its target molecule to . facilitate separation of complexed from uncomplexed forms of one or both of the proteins, as well as to accommodate automation of the assay. Binding of a test compound to a FOXO3a protein, or interaction of a FOXO3a protein with a target molecule in the presence and absence of a candidate compound, can be accomplished in any vessel suitable for containing the reactants. Examples of such vessels include microtitre plates, test tubes, and micro-centrifuge tubes. In one embodiment, a fusion protein can be provided which adds a domain that allows one or both of the proteins to be bound to a matrix. For example, glutathione-S-transferase/FOXO3a fusion proteins or glutathione-S-transferase/target fusion proteins can be adsorbed onto glutathione sepharose beads (Sigma Chemical, St. Louis, MO) or glutathione derivatized microtitre plates, which are then combined with the test compound or the test compound and either the non-adsorbed target protein or FOXO3a protein, and the mixture incubated under conditions conducive to complex formation (e.g., at physiological conditions for salt and pH). Following incubation, the beads or microtitre plate wells are washed to remove any unbound components, the matrix immobilized in the case of beads, complex determined either directly or indirectly, for example, as described above. Alternatively, the complexes can be dissociated from the matrix, and the level of FOXO3a binding or activity determined using standard techniques. Other techniques for immobilizing proteins on matrices can also be used in the screening assays of the invention. For example, either a FOXO3a protein or a FOXO3a target molecule can be immobilized utilizing conjugation of biotin and streptavidin. Biotinylated FOXO3a protein or target molecules can be prepared from biotin-NHS (N-hydroxy-succinimide) using techniques known in the art (e.g., biotinylation kit, Pierce Chemicals, Rockford, IL), and immobilized in the wells of streptavidin-coated 96 well plates (Pierce Chemical). Alternatively, antibodies reactive with FOXO3a protein or target molecules but which do not interfere with binding of the ^• FOXO3a protein to its target molecule can be derivatized to the wells of the plate, and unbound target or FOXO3a protein trapped in the wells by antibody conjugation. Methods for detecting such complexes, in addition to those described above for the GST-immobilized complexes, include immunodetection of complexes using antibodies reactive with the FOXO3a protein or target molecule, as well as enzyme-linked assays which rely on detecting an enzymatic activity associated with the FOXO3a protein or target molecule. In another embodiment, modulators of FOXO3a expression are identified in a method wherein a cell is contacted with a candidate compound and the expression of FOXO3a mRNA or protein in the cell is determined. The level of expression of FOXO3a mRNA or protein in the presence of the candidate compound is compared to the level of expression of FOXO3a mRNA or protein in the absence of the candidate compound. The candidate compound can then be identified as a modulator of FOXO3 expression based on this comparison. For example, when expression of FOXO3a mRNA or protein is greater (statistically significantly greater) in the presence of the candidate compound than in its absence, the candidate compound is identified as a stimulator of FOXO3a mRNA or protein expression. Alternatively, when expression of FOXO3a mRNA or protein is less (statistically significantly less) in the presence of the candidate compound than in its absence, the candidate compound is identified as an inhibitor of FOXO3a mRNA or protein expression. The level of FOXO3a mRNA or protein expression in the cells can be determined by methods described herein for detecting FOXO3a mRNA or protein. In yet another aspect of the invention, the FOXO3a proteins can be used as "bait proteins" in a two-hybrid assay or three-hybrid assay (see, e.g., U.S. Patent No. 5,283,317; Zervos et al. (1993) Cell 72:223-232; Madura et al (1993) J. Biol. Chem. 268:12046-12054; Bartel et al (1993) Biotechniques 14:920-924; Iwabuchi et al. (1993) Oncogene 8:1693-1696; and Brent WO94/10300), to identify other proteins, which bind to or interact with FOXO3a ("FOXO3a-binding proteins" or "FOXO3a-bp") and are involved in FOXO3a activity. Such FOXO3a-binding proteins are also likely to be involved in the propagation of signals by the FOXO3a proteins or FOXO3a targets as, for example, downstream elements of a FOXO3a-mediated signaling pathway. Alternatively, such FOXO3a-binding proteins are likely to be FOXO3 inhibitors. The two-hybrid system is based on the modular nature of most transcription factors, which consist of separable DNA-binding and activation domains. Briefly, the assay utilizes two different DNA constructs. In one construct, the gene that codes for a FOXO3a protein is fused to a gene encoding the DNA binding domain of a known transcription factor (e.g., GAL-4). In the other construct, a DNA sequence, from a library of DNA sequences, that encodes an unidentified protein ("prey" or "sample") is fused to a gene that codes for the activation domain of the known transcription factor. If the "bait" and the "prey" proteins are able to interact, in vivo, forming a FOXO3a- dependent complex, the DNA-binding and activation domains of the transcription factor are brought into close proximity. This proximity allows transcription of a reporter gene (e.g., LacZ) which is operably linked to a transcriptional regulatory site responsive to the transcription factor. Expression of the reporter gene can be detected and cell colonies containing the functional transcription factor can be isolated and used to obtain the cloned gene which encodes the protein which interacts with the FOXO3a protein. In another aspect, the invention pertains to a combination of two or more of the assays described herein. For example, a modulating agent can be identified using a cell-based or a cell free assay, and the ability of the agent to modulate the activity of a FOXO3a protein can be confirmed in vivo, e.g., in an animal such as an animal model for infertility, as described herein. This invention further pertains to novel agents identified by the above- described screening assays. Accordingly, it is within the scope of this invention to further use an agent identified as described herein in an appropriate animal model. For example, an agent identified as described herein (e.g., a FOXO3a modulating agent, an antisense FOXO3a nucleic acid molecule, a FOXO3a-specifιc antibody, or a FOXO3a- binding partner) can be used in an animal model to determine the efficacy, toxicity, or side effects of treatment with such an agent. Alternatively, an agent identified as described herein can be used in an animal model to determine the mechanism of action of such an agent. Furthermore, this invention pertains to uses of novel agents identified by the above-described screening assays for treatments as described herein. Any of the compounds, including but not limited to compounds such as those identified in the foregoing assay systems, may be tested for the ability to modulate ovarian follicular initiation, modulate fertility, treat infertility, or treat hormone-related diseases or disorders. Cell-based and animal model-based assays for the identification of compounds exhibiting such an ability to modulate ovarian follicular initiation, modulate fertility, treat infertility, or treat hormone-related diseases or disorders are described herein. In one aspect, cell-based systems, as described herein, may be used to identify compounds which may act to modulate ovarian follicular initiation, modulate fertility, treat infertility, or treat hormone-related diseases or disorders. For example, such cell systems may be exposed to a compound, suspected of exhibiting an ability to modulate ovarian follicular initiation, modulate fertility, treat infertility, or treat hormone-related diseases or disorders, at a sufficient concentration and for a time sufficient to elicit such an amelioration of disease symptoms in the exposed cells. After exposure, the cells are examined to determine whether one or more of the disease phenotypes, e.g., infertility, for example, has been altered to resemble a more normal or more wild type disease phenotype. In addition, animal-based disease systems, such as those described herein, may be used to identify compounds capable of modulating ovarian follicular initiation, modulating fertility, treating infertility, or treating hormone-related diseases or disorders. Such animal models may be used as test substrates for the identification of drugs, pharmaceuticals, therapies, and interventions which may be effective in modulating ovarian follicular initiation, modulating fertility, treating infertility, or treating hormone-related diseases or disorders, e.g., migraine or hormone dependent tumors. Additionally, gene expression patterns may be utilized to assess the ability of a compound to modulating ovarian follicular initiation, modulating fertility, treating infertility, or treating hormone-related diseases or disorders. For example, the expression pattern of one or more genes may form part of a "gene expression profile" or "transcriptional profile" which may be then be used in such an assessment. "Gene expression profile" or "transcriptional profile", as used herein, includes the pattern of mRNA expression obtained for a given tissue or cell type under a given set of conditions. Gene expression profiles may be generated, for example, by utilizing a differential display procedure, Northern analysis and/or RT-PCR. In one embodiment, FOXO3a gene sequences may be used as probes and/or PCR primers for the generation and corroboration of such gene expression profiles. Gene expression profiles may be characterized for known states within the cell- and/or animal-based model systems. Subsequently, these known gene expression profiles may be compared to ascertain the effect a test compound has to modify such gene expression profiles, and to cause the profile to more closely resemble that of a more desirable profile.

II. Predictive Medicine: The present invention also pertains to the field of predictive medicine in which diagnostic assays, prognostic assays, and monitoring clinical trials are used for prognostic (predictive) puφoses to thereby treat an individual prophylactically. Accordingly, one aspect of the present invention relates to diagnostic assays for determining FOXO3a protein and/or nucleic acid expression as well as FOXO3a activity, in the context of a biological sample (e.g., blood, serum, cells, e.g., endothelial cells, or tissue, e.g., ovarian tissue) to thereby determine whether an individual is afflicted with POF. The invention also provides for prognostic (or predictive) assays for determining whether an individual is at risk of developing POF. For example, mutations in a FOXO3a gene can be assayed for in a biological sample. Such assays can be used for prognostic or predictive puφose to thereby phophylactically treat an individual prior to the onset of a POF. Another aspect of the invention pertains to monitoring the influence of

FOXO3a modulators on the expression or activity of FOXO3a in clinical trials. These and other agents are described in further detail in the following sections. A. Prognostic and Diagnostic Assays To determine whether a subject is afflicted with POF, or is at risk for developing POF, a biological sample may be obtained from a subject and the biological sample may be contacted with a compound or an agent capable of detecting a FOXO3a protein or nucleic acid (e.g., mRNA or genomic DNA) that encodes a FOXO3a protein, in the biological sample. A preferred agent for detecting FOXO3a mRNA or genomic DNA is a labeled nucleic acid probe capable of hybridizing to FOXO3a mRNA or genomic DNA. The nucleic acid probe can be, for example, the FOXO3a nucleic acid set forth in SEQ ID NO:l, or a portion thereof, such as an oligonucleotide of at least 1 , 20, 25, 30, 25, 40, 45, 50, 100, 250 or 500 nucleotides in length and sufficient to specifically hybridize under stringent conditions to FOXO3a mRNA or genomic DNA. Other suitable probes for use in the diagnostic assays of the invention are described herein. The term "biological sample" is intended to include tissues, cells, and biological fluids isolated from a subject, as well as tissues, cells, and fluids present within a subject. That is, the detection method of the invention can be used to detect FOXO3a mRNA, protein, or genomic DNA in a biological sample in vitro as well as in vivo. For example, in vitro techniques for detection of FOXO3a mRNA include Northern hybridizations and in situ hybridizations. In vitro techniques for detection of FOXO3a protein include enzyme linked immunosorbent assays (ELISAs), Western blots, immunoprecipitations and immunofluorescence. In vitro techniques for detection of FOXO3a genomic DNA include Southern hybridizations. Furthermore, in vivo techniques for detection of FOXO3a protein include introducing into a subject a labeled anti-FOXO3a antibody. For example, the antibody can be labeled with a radioactive marker whose presence and location in a subject can be detected by standard imaging techniques. In another embodiment, the methods further involve obtaining a control biological sample from a control subject, contacting the control sample with a compound or agent capable of detecting FOXO3a protein, mRNA, or genomic DNA, such that the presence of FOXO3a protein, mRNA or genomic DNA is detected in the biological sample, and comparing the presence of FOXO3a protein, mRNA or genomic DNA in the control sample with the presence of FOXO3a protein, mRNA or genomic DNA in the test sample. Analysis of one or more FOXO3a polymoφhic regions in a subject can be useful for predicting whether a subject has or is likely to develop POF. In preferred embodiments, the methods of the invention can be characterized as comprising detecting, in a sample of cells from the subject, the presence or absence of a specific allelic variant of one or more polymoφhic regions of a FOXO3a gene. The allelic differences can be: (i) a difference in the identity of at least one nucleotide or (ii) a difference in the number of nucleotides, which difference can be a single nucleotide or several nucleotides. The invention also provides methods for detecting differences in an FOXO3a gene such as chromosomal rearrangements, e.g., chromosomal dislocation. The invention can also be used in prenatal diagnostics. A preferred detection method is allele specific hybridization using probes overlapping the polymoφhic site and having about 5, 10, 20, 25, or 30 nucleotides around the polymoφhic region. In a preferred embodiment of the invention, several probes capable of hybridizing specifically to allelic variants are attached to a solid phase support, e.g., a "chip". Oligonucleotides can be bound to a solid support by a variety of processes, including lithography. For example a chip can hold up to 250,000 oligonucleotides (GeneChip, Affymetrix). Mutation detection analysis using these chips comprising oligonucleotides, also termed "DNA probe arrays" is described e.g., in Cronin et αl. (1996) Human Mutation 7:244. In one embodiment, a chip comprises all the allelic variants of at least one polymoφhic region of a gene. The solid phase support is then contacted with a test nucleic acid and hybridization to the specific probes is detected. Accordingly, the identity of numerous allelic variants of one or more genes can be identified in a simple hybridization experiment. For example, the identity of the allelic variant of the nucleotide polymoφhism in the 5' upstream regulatory element can be determined in a single hybridization experiment. In other detection methods, it is necessary to first amplify at least a portion of a FOXO3a gene prior to identifying the allelic variant. Amplification can be performed, e.g., by PCR and/or LCR (see Wu and Wallace, (1989) Genomics 4:560), according to methods known in the art. In one embodiment, genomic DNA of a cell is exposed to two PCR primers and amplification for a number of cycles sufficient to produce the required amount of amplified DNA. In preferred embodiments, the primers are located between 150 and 350 base pairs apart. Alternative amplification methods include: self sustained sequence replication (Guatelli, J.C. et αl., 1990, Proc. Nαtl Acαd. Sci. USA 87:1874-1878), transcriptional amplification system (Kwoh, D.Y. et αl., 1989, Proc. Nαtl. Acαd. Sci. USA 86:1173-1177), Q-Beta Replicase (Lizardi, P.M. et αl., 1988, Bio/Technology 6:1197), and self-sustained sequence replication (Guatelli et al, (1989) Proc. Nat. Acad. Sci. 87:1874), and nucleic acid based sequence amplification (NABSA), or any other nucleic acid amplification method, followed by the detection of the amplified molecules using techniques well known to those of skill in the art. These detection schemes are especially useful for the detection of nucleic acid molecules if such molecules are present in very low numbers. In one embodiment, any of a variety of sequencing reactions known in the art can be used to directly sequence at least a portion of a FOXO3a gene and detect allelic variants, e.g., mutations, by comparing the sequence of the sample sequence with the corresponding reference (control) sequence. Exemplary sequencing reactions include those based on techniques developed by Maxam and Gilbert (Proc. Natl Acad Sci USA (1977) 74:560) or Sanger (Sanger et al. (1977) Proc. Nat. Acad. Sci 74:5463). It is also contemplated that any of a variety of automated sequencing procedures may be utilized when performing the subject assays (Biotechniques (1995) 19:448), including sequencing by mass spectrometry (see, for example, U.S. Patent No. 5,547,835 and international patent application Publication Number WO 94/16101 , entitled DNA Sequencing by Mass Spectrometry by H. Koster; U.S. Patent No. 5,547,835 and international patent application Publication Number WO 94/21822 entitled "DNA Sequencing by Mass Spectrometry Via Exonuclease Degradation" by H. Koster), and U.S Patent No.5,605,798 and International Patent Application No. PCT US96/03651 entitled E>N Diagnostics Based on Mass Spectrometry by H. Koster; Cohen et al.

(1996) Adv Chromatogr 36:127-162; and Griffin et al. (1993) Appl Biochem Biotechnol 38:147-159). It will be evident to one skilled in the art that, for certain embodiments, the occurrence of only one, two or three of the nucleic acid bases need be determined in the sequencing reaction. For instance, A-track or the like, e.g., where only one nucleotide is detected, can be carried out. Yet other sequencing methods are disclosed, e.g., in U.S. Patent No. 5,580,732 entitled "Method of DNA sequencing employing a mixed DNA-polymer chain probe" and U.S. Patent No. 5,571,676 entitled "Method for mismatch-directed in vitro DNA sequencing". In some cases, the presence of a specific allele of a FOXO3a gene in

DNA from a subject can be shown by restriction enzyme analysis. For example, a specific nucleotide polymoφhism can result in a nucleotide sequence comprising a restriction site which is absent from the nucleotide sequence of another allelic variant. In a further embodiment, protection from cleavage agents (such as a nuclease, hydroxylamine or osmium tetroxide and with piperidine) can be used to detect mismatched bases in RNA/RNA DNA/DNA, or RNA/DNA heteroduplexes (Myers, et al. (1985) Science 230:1242). In general, the technique of "mismatch cleavage" starts by providing heteroduplexes formed by hybridizing a control nucleic acid, which is optionally labeled, e.g., RNA or DNA, comprising a nucleotide sequence of an FOXO3a allelic variant with a sample nucleic acid, e.g., RNA or DNA, obtained from a tissue sample. The double-stranded duplexes are treated with an agent which cleaves single- stranded regions of the duplex such as duplexes formed based on basepair mismatches between the control and sample strands. For instance, RNA/DNA duplexes can be treated with RNase and DNA/DNA hybrids treated with SI nuclease to enzymatically digest the mismatched regions. In other embodiments, either DNA/DNA or RNA/DNA duplexes can be treated with hydroxylamine or osmium tetroxide and with piperidine in order to digest mismatched regions. After digestion of the mismatched regions, the resulting material is then separated by size on denaturing polyacrylamide gels to determine whether the control and sample nucleic acids have an identical nucleotide sequence or in which nucleotides they are different. See, for example, Cotton et al. (1988) Proc. NatlAcad Sci USA 85:4397; Saleeba et al (1992) Methods Enzymol 217:286-295. In a preferred embodiment, the control or sample nucleic acid is labeled for detection. In another embodiment, an allelic variant can be identified by denaturing high-performance liquid chromatography (DHPLC) (Oefner and Underhill, (1995) Am. J. Human Gen. 57:Suppl. A266). DHPLC uses reverse-phase ion-pairing chromatography to detect the heteroduplexes that are generated during amplification of PCR fragments from individuals who are heterozygous at a particular nucleotide locus within that fragment (Oef er and Underhill (1995) Am. J. Human Gen. 57:Suppl. A266). In general, PCR products are produced using PCR primers flanking the DNA of interest. DHPLC analysis is carried out and the resulting chromatograms are analyzed to identify base pair alterations or deletions based on specific chromatographic profiles (see O'Donovan et al. (1998) Genomics 52:44-49). In other embodiments, alterations in electrophoretic mobility is used to identify the type of FOXO3a allelic variant. For example, single strand conformation polymoφhism (SSCP) may be used to detect differences in electrophoretic mobility between mutant and wild type nucleic acids (Orita et al. (1989) Proc Natl. Acad. Sci USA 86:2766; see also Cotton (1993) Mutat Res 285:125-144; and Hayashi (1992)

Genet Anal Tech Appl 9:73-79). Single-stranded DNA fragments of sample and control nucleic acids are denatured and allowed to renature. The secondary structure of single- stranded nucleic acids varies according to sequence, the resulting alteration in electrophoretic mobility enables the detection of even a single base change. The DNA fragments may be labeled or detected with labeled probes. The sensitivity of the assay may be enhanced by using RNA (rather than DNA), in which the secondary structure is more sensitive to a change in sequence. In another preferred embodiment, the subject method utilizes heteroduplex analysis to separate double stranded heteroduplex molecules on the basis of changes in electrophoretic mobility (Keen et al. (1991) Trends Genet 7:5). In yet another embodiment, the identity of an allelic variant of a polymoφhic region is obtained by analyzing the movement of a nucleic acid comprising the polymoφhic region in polyacrylamide gels containing a gradient of denaturant is assayed using denaturing gradient gel electrophoresis (DGGE) (Myers et al. (1985) Nature 13:495). When DGGE is used as the method of analysis, DNA will be modified to insure that it does not completely denature, for example by adding a GC clamp of approximately 40 bp of high-melting GC-rich DNA by PCR. In a further embodiment, a temperature gradient is used in place of a denaturing agent gradient to identify differences in the mobility of control and sample DNA (Rosenbaum and Reissner (1987) Biophys Chem 265:1275). Examples of techniques for detecting differences of at least one nucleotide between two nucleic acids include, but are not limited to, selective oligonucleotide hybridization, selective amplification, or selective primer extension. For example, oligonucleotide probes may be prepared in which the known polymoφhic nucleotide is placed centrally (allele-specific probes) and then hybridized to target DNA under conditions which permit hybridization only if a perfect match is found (Saiki et al. (1986) Nature 324:163); Saiki et al (1989) Proc. Natl Acad. Sci USA 86:6230; and Wallace et al. (1979) Nucl. Acids Res. 6:3543). Such allele specific oligonucleotide hybridization techniques may be used for the simultaneous detection of several nucleotide changes in different polylmoφhic regions of FOXO3a. For example, oligonucleotides having nucleotide sequences of specific allelic variants are attached to a hybridizing membrane and this membrane is then hybridized with labeled sample nucleic acid. Analysis of the hybridization signal will then reveal the identity of the nucleotides of the sample nucleic acid. Alternatively, allele specific amplification technology which depends on selective PCR amplification may be used in conjunction with the instant invention. Oligonucleotides used as primers for specific amplification may carry the allelic variant of interest in the center of the molecule (so that amplification depends on differential hybridization) (Gibbs et al. (1989) Nucleic Acids Res. 17:2437-2448) or at the extreme 3' end of one primer where, under appropriate conditions, mismatch can prevent, or reduce polymerase extension (Prossner (1993) Tibtech 11 :238; Newton et al. (1989) Nucl. Acids Res. 17:2503). This technique is also termed "PROBE" for Probe Oligo Base Extension. In addition it may be desirable to introduce a novel restriction site in the region of the mutation to create cleavage-based detection (Gasparini et al. (1992) Mol. Cell Probes 6:1). In another embodiment, identification of the allelic variant is carried out using an oligonucleotide ligation assay (OLA), as described, e.g., in U.S. Patent No. 4,998,617 and in Landegren, U. et al, (1988) Science 241 : 1077-1080. The OLA protocol uses two oligonucleotides which are designed to be capable of hybridizing to abutting sequences of a single strand of a target. One of the oligonucleotides is linked to a separation marker, e.g., biotinylated, and the other is detectably labeled. If the precise complementary sequence is found in a target molecule, the oligonucleotides will hybridize such that their termini abut, and create a ligation substrate. Ligation then permits the labeled oligonucleotide to be recovered using avidin, or another biotin ligand. Nickerson, D.A. et al. have described a nucleic acid detection assay that combines attributes of PCR and OLA (Nickerson, D. A. et al, (1990) Proc. Natl. Acad. Sci. (U.S.A.) 87:8923-8927. In this method, PCR is used to achieve the exponential amplification of target DNA, which is then detected using OLA. Several techniques based on this OLA method have been developed and can be used to detect specific allelic variants of a polymoφhic region of an FOXO3a gene. For example, U.S. Patent No. 5593826 discloses an OLA using an oligonucleotide having 3'-amino group and a 5'-phosphorylated oligonucleotide to form a conjugate having a phosphoramidate linkage. In another variation of OLA described in Tobe et al. ((1996) Nucleic Acids Res 24: 3728), OLA combined with PCR permits typing of two alleles in a single microtiter well. By marking each of the allele-specific primers with a unique hapten, i.e. digoxigenin and fluorescein, each OLA reaction can be detected by using hapten specific antibodies that are labeled with different enzyme reporters, alkaline phosphatase or horseradish peroxidase. This system permits the detection of the two alleles using a high throughput format that leads to the production of two different colors. The invention further provides methods for detecting single nucleotide polymoφhisms in a FOXO3a gene. Because single nucleotide polymoφhisms constitute sites of variation flanked by regions of invariant sequence, their analysis requires no more than the determination of the identity of the single nucleotide present at the site of variation and it is unnecessary to determine a complete gene sequence for each subject. Several methods have been developed to facilitate the analysis of such single nucleotide polymoφhisms.

In one embodiment, the single base polymoφhism can be detected by using a specialized exonuclease-resistant nucleotide, as disclosed, e.g., in Mundy, C. R. (U.S. Patent No. 4,656,127). According to the method, a primer complementary to the allelic sequence immediately 3' to the polymoφhic site is permitted to hybridize to a target molecule obtained from a particular animal or human. If the polymoφhic site on the target molecule contains a nucleotide that is complementary to the particular exonuclease-resistant nucleotide derivative present, then that derivative will be incoφorated onto the end of the hybridized primer. Such incoφoration renders the primer resistant to exonuclease, and thereby permits its detection. Since the identity of the exonuclease-resistant derivative of the sample is known, a finding that the primer has become resistant to exonucleases reveals that the nucleotide present in the polymoφhic site of the target molecule was complementary to that of the nucleotide derivative used in the reaction. This method has the advantage that it does not require the determination of large amounts of extraneous sequence data. In another embodiment of the invention, a solution-based method is used for determining the identity of the nucleotide of a polymoφhic site (Cohen, D. et al. (French Patent 2,650,840; PCT Application No. WO91/02087). As in the Mundy method of U.S. Patent No. 4,656,127, a primer is employed that is complementary to allelic sequences immediately 3' to a polymoφhic site. The method determines the identity of the nucleotide of that site using labeled dideoxynucleotide derivatives, which, if complementary to the nucleotide of the polymoφhic site will become incoφorated onto the terminus of the primer. An alternative method, known as Genetic Bit Analysis or GBA™ is described by Goelet, P. et al. (PCT Application No. 92/15712). The method of Goelet, P. et al. uses mixtures of labeled terminators and a primer that is complementary to the sequence 3' to a polymoφhic site. The labeled terminator that is incoφorated is thus determined by, and complementary to, the nucleotide present in the polymoφhic site of the target molecule being evaluated. In contrast to the method of Cohen et al. (French Patent 2,650,840; PCT Appln. No. WO91/02087) the method of Goelet, P. et al. is preferably a heterogeneous phase assay, in which the primer or the target molecule is immobilized to a solid phase. Several primer-guided nucleotide incoφoration procedures for assaying polymoφhic sites in DNA have been described (Komher, J. S. et al, Nucl. Acids. Res. 17:7779-7784 (1989); Sokolov, B. P., Nucl. Acids Res. 18:3671 (1990); Syvanen, A. -C, et al, Genomics 8:684-692 (1990); Kuppuswamy, M. N. et al, Proc. Natl. Acad. Sci. (U.S.A.) 88:1143-1147 (1991); Prezant, T. R. et al, Hum. Mutat. 1 :159-164 (1992); Ugozzoli, L. et al, GATA 9:107-112 (1992); Nyren, P. et al., Anal. Biochem.

208:171-175 (1993)). These methods differ from GBA™ in that they all rely on the incoφoration of labeled deoxynucleotides to discriminate between bases at a polymoφhic site. In such a format, since the signal is proportional to the number of deoxynucleotides incoφorated, polymoφhisms that occur in runs of the same nucleotide can result in signals that are proportional to the length of the run (Syvanen, A. -C, et al, Amer.J. Hum. Genet. 52:46-59 (1993)). For determining the identity of the allelic variant of a polymoφhic region located in the coding region of a FOXO3a gene, yet other methods than those described above can be used. For example, identification of an allelic variant which encodes a mutated FOXO3a protein can be performed by using an antibody specifically recognizing the mutant protein in, e.g., immunohistochemistry or immunoprecipitation. Antibodies to wild-type FOXO3a or mutated forms of FOXO3a proteins can be prepared according to methods known in the art. Alternatively, one can also measure an activity of a FOXO3a protein, such as binding to a FOXO3a ligand. Binding assays are known in the art and involve, e.g., obtaining cells from a subject, and performing binding experiments with a labeled lipid, to determine whether binding to the mutated form of the protein differs from binding to the wild-type of the protein. Antibodies directed against reference or mutant FOXO3a polypeptides or allelic variant thereof, which are discussed above, may also be used in disease diagnostics and prognostics. Such diagnostic methods, may be used to detect abnormalities in the level of FOXO3a polypeptide expression, or abnormalities in the structure and or tissue, cellular, or subcellular location of an FOXO3a polypeptide. Structural differences may include, for example, differences in the size, electronegativity, or antigenicity of the mutant FOXO3a polypeptide relative to the normal FOXO3a polypeptide. Protein from the tissue or cell type to be analyzed may easily be detected or isolated using techniques which are well known to one of skill in the art, including but not limited to Western blot analysis. For a detailed explanation of methods for carrying out Western blot analysis, see Sambrook et al, 1989, supra, at Chapter 18. The protein detection and isolation methods employed herein may also be such as those described in Harlow and Lane, for example (Harlow, E. and Lane, D., 1988, "Antibodies: A Laboratory Manual", Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York), which is incoφorated herein by reference in its entirety. This can be accomplished, for example, by immunofluorescence techniques employing a fluorescently labeled antibody (see below) coupled with light microscopic, flow cytometric, or fluorimetric detection. The antibodies (or fragments thereof) useful in the present invention may, additionally, be employed histologically, as in immunofluorescence or immunoelectron microscopy, for in situ detection of FOX O3 a polypeptides. In situ detection may be accomplished by removing a histological specimen from a subject, and applying thereto a labeled antibody of the present invention. The antibody (or fragment) is preferably applied by overlaying the labeled antibody (or fragment) onto a biological sample. Through the use of such a procedure, it is possible to determine not only the presence of the FOXO3a polypeptide, but also its distribution in the examined tissue. Using the present invention, one of ordinary skill will readily perceive that any of a wide variety of histological methods (such as staining procedures) can be modified in order to achieve such in situ detection. Often a solid phase support or carrier is used as a support capable of binding an antigen or an antibody. Well-known supports or carriers include glass, polystyrene, polypropylene, polyethylene, dextran, nylon, amylases, natural and modified celluloses, polyacrylamides, gabbros, and magnetite. The nature of the carrier can be either soluble to some extent or insoluble for the puφoses of the present invention. The support material may have virtually any possible structural configuration so long as the coupled molecule is capable of binding to an antigen or antibody. Thus, the support configuration may be spherical, as in a bead, or cylindrical, as in the inside surface of a test tube, or the external surface of a rod. Alternatively, the surface may be flat such as a sheet, test strip, etc. Preferred supports include polystyrene beads. Those skilled in the art will know many other suitable carriers for binding antibody or antigen, or will be able to ascertain the same by use of routine experimentation. One means for labeling an anti-FOXO3a polypeptide specific antibody is via linkage to an enzyme and use in an enzyme immunoassay (EIA) (Voller, "The Enzyme Linked Immunosorbent Assay (ELISA)", Diagnostic Horizons 2: 1 -7, 1978, Microbiological Associates Quarterly Publication, Walkersville, MD; Voller, et al, J. Clin. Pathol 31 :507-520 (1978); Butler, Meth. Enzymol. 73:482-523 (1981); Maggio, (ed.) Enzyme Immunoassay, CRC Press, Boca Raton, FL, 1980; Ishikawa, et al, (eds.) Enzyme Immunoassay, Kgaku Shoin, Tokyo, 1981). The enzyme which is bound to the antibody will react with an appropriate substrate, preferably a chromogenic substrate, in such a manner as to produce a chemical moiety which can be detected, for example, by spectrophotometric, fluorimetric or by visual means. Enzymes which can be used to detectably label the antibody include, but are not limited to, malate dehydrogenase, staphylococcal nuclease, delta-5-steroid isomerase, yeast alcohol dehydrogenase, alpha- glycerophosphate, dehydrogenase, triose phosphate isomerase, horseradish peroxidase, alkaline phosphatase, asparaginase, glucose oxidase, beta-galactosidase, ribonuclease, urease, catalase, glucose-6-phosphate dehydrogenase, glucoamylase and acetylcholinesterase. The detection can be accomplished by colorimetric methods which employ a chromogenic substrate for the enzyme. Detection may also be accomplished by visual comparison of the extent of enzymatic reaction of a substrate in comparison with similarly prepared standards. Detection may also be accomplished using any of a variety of other immunoassays. For example, by radioactively labeling the antibodies or antibody fragments, it is possible to detect fingeφrint gene wild type or mutant peptides through the use of a radioimmunoassay (RIA) (see, for example, Weintraub, B., Principles of Radioimmunoassays, Seventh Training Course on Radioligand Assay Techniques, The Endocrine Society, March, 1986, which is incoφorated by reference herein). The radioactive isotope can be detected by such means as the use of a gamma counter or a scintillation counter or by autoradiography. It is also possible to label the antibody with a fluorescent compound.

When the fluorescently labeled antibody is exposed to light of the proper wave length, its presence can then be detected due to fluorescence. Among the most commonly used fluorescent labeling compounds are fluorescein isothiocyanate, rhodamine, phycoerythrin, phycocyanin, allophycocyanin, o-phthaldehyde and fluorescamine.

The antibody can also be detectably labeled using fluorescence emitting metals such as

152 Eu, or others of the lanthanide series. These metals can be attached to the antibody using such metal chelating groups as diethylenetriaminepentacetic acid (DTP A) or ethylenediaminetetraacetic acid (EDTA). The antibody also can be detectably labeled by coupling it to a chemiluminescent compound. The presence of the chemiluminescent-tagged antibody is then determined by detecting the presence of luminescence that arises during the course of a chemical reaction. Examples of particularly useful chemiluminescent labeling compounds are luminol, isoluminol, theromatic acridinium ester, imidazole, acridinium salt and oxalate ester. Likewise, a bioluminescent compound may be used to label the antibody of the present invention. Bioluminescence is a type of chemiluminescence found in biological systems in, which a catalytic protein increases the efficiency of the chemiluminescent reaction. The presence of a bioluminescent protein is determined by detecting the presence of luminescence. Important bioluminescent compounds for puφoses of labeling are luciferin, luciferase and aequorin.

If a polymoφhic region is located in an exon, either in a coding or non-coding portion of the gene, the identity of the allelic variant can be determined by determining the molecular structure of the mRNA, pre-mRNA, or cDNA. The molecular structure can be determined using any of the above described methods for determining the molecular structure of the genomic DNA. The methods described herein may be performed, for example, by utilizing pre-packaged diagnostic kits, such as those described above, comprising at least one probe or primer nucleic acid described herein, which may be conveniently used, e.g., to determine whether a subject has or is at risk of developing a disease associated with a specific FOXO3a allelic variant.

Sample nucleic acid to be analyzed by any of the above-described diagnostic and prognostic methods can be obtained from any cell type or tissue of a subject. For example, a subject's bodily fluid (e.g. blood) can be obtained by known techniques (e.g. venipuncture). Alternatively, nucleic acid tests can be performed on dry samples (e.g. hair or skin). Fetal nucleic acid samples can be obtained from maternal blood as described in International Patent Application No. WO91/07660 to Bianchi. Alternatively, amniocytes or chorionic villi may be obtained for performing prenatal testing. Diagnostic procedures may also be performed in situ directly upon tissue sections (fixed and/or frozen) of subject tissue obtained from biopsies or resections, such that no nucleic acid purification is necessary. Nucleic acid reagents may be used as probes and or primers for such in situ procedures (see, for example, Nuovo, G.J., 1992, PCR in situ hybridization: protocols and applications, Raven Press, NY). In addition to methods which focus primarily on the detection of one nucleic acid sequence, profiles may also be assessed in such detection schemes.

Fingeφrint profiles may be generated, for example, by utilizing a differential display procedure, Northern analysis and/or RT-PCR.

B. Monitoring of Effects During Clinical Trials The present invention further provides methods for determining the effectiveness of a FOXO3a modulator (e.g., a FOXO3a modulator identified herein) in modulating ovarian follicular initiation, modulating fertility, treating infertility, or treating hormone-related diseases or disorders, in a subject. For example, the effectiveness of a FOXO3a modulator in increasing or decreasing FOXO3a gene expression, protein levels, or in upregulating or downregulatmg FOXO3a activity, can be monitored in clinical trials of subjects exhibiting increased or decreased FOXO3a gene expression, protein levels, or upregulated or downregulated FOXO3a activity. Alternatively, the effectiveness of a FOXO3a modulator increasing or decreasing FOXO3a gene expression, protein levels, or in upregulating or downregulating FOXO3a activity, can be monitored in clinical trials of subjects exhibiting increased or decreased FOXO3a gene expression, protein levels, or FOXO3a activity. In such clinical trials, the expression or activity of a FOXO3a gene, and preferably, other genes that have been implicated in, for example, follicular initiation can be used as a "read out" or marker of the phenotype of a particular cell. For example, and not by way of limitation, genes, including FOXO3a, that are modulated in cells by treatment with an agent which modulates FOXO3a activity (e.g., identified in a screening assay as described herein) can be identified. Thus, to study the effect of agents which modulate FOXO3a activity on subjects suffering from treating infertility, or treating hormone-related diseases or disorders, or agents to be used as contraceptives, for example, a clinical trial, cells can be isolated and RNA prepared and analyzed for the levels of expression of FOXO3a and other genes implicated in follicular initiation. The levels of gene expression (e.g., a gene expression pattern) can be quantified by Northern blot analysis or RT-PCR, as described herein, or alternatively by measuring the amount of protein produced, by one of the methods described herein, or by measuring the levels of activity of FOXO3a or other genes. In this way, the gene expression pattern can serve as a marker, indicative of the physiological response of the cells to the agent which modulates FOXO3a activity. This response state may be determined before, and at various points during treatment of the individual with the agent which modulates FOXO3a activity. In a preferred embodiment, the present invention provides a method for monitoring the effectiveness of treatment of a subject with an agent which modulates FOXO3a activity (e.g., an agonist, antagonist, peptidomimetic, protein, peptide, nucleic acid, siRNA, or small molecule identified by the screening assays described herein) including the steps of (i) obtaining a pre-administration sample from a subject prior to administration of the agent; (ii) detecting the level of expression of a FOXO3a protein, mRNA, or genomic DNA in the pre-administration sample; (iii) obtaining one or more post-administration samples from the subject; (iv) detecting the level of expression or activity of the FOXO3a protein, mRNA, or genomic DNA in the post-administration samples; (v) comparing the level of expression or activity of the FOXO3a protein, mRNA, or genomic DNA in the pre-administration sample with the FOXO3a protein, mRNA, or genomic DNA in the post administration sample or samples; and (vi) altering the administration of the agent to the subject accordingly. For example, increased administration of the agent may be desirable to increase the expression or activity of FOXO3a to higher levels than detected, i.e., to increase the effectiveness of the agent. Alternatively, decreased administration of the agent may be desirable to decrease expression or activity of FOXO3a to lower levels than detected, i.e. to decrease the effectiveness of the agent. According to such an embodiment, FOXO3a expression or activity may be used as an indicator of the effectiveness of an agent, even in the absence of an observable phenotypic response.

III. Methods of Treatment: The present invention provides for both prophylactic and therapeutic methods of treating a subject, e.g., a human, at risk of (or susceptible to) POF, infertility, or hormone-related diseases or disorders. With regard to both prophylactic and therapeutic methods of treatment, such treatments may be specifically tailored or modified, based on knowledge obtained from the field of pharmacogenomics. "Pharmacogenomics," as used herein, refers to the application of genomics technologies such as gene sequencing, statistical genetics, and gene expression analysis to d gs in clinical development and on the market. More specifically, the term refers to the study of how a patient's genes determine his or her response to a drug (e.g., a patient's "drug response phenotype", or "drug response genotype"). Thus, another aspect of the invention provides methods for tailoring a subject's prophylactic or therapeutic treatment with either the FOXO3a molecules of the present invention or FOXO3a modulators according to that individual's drug response genotype. Pharmacogenomics allows a clinician or physician to target prophylactic or therapeutic treatments to patients who will most benefit from the treatment and to avoid treatment of patients who will experience toxic drug-related side effects.

A. Prophylactic Methods In one aspect, the invention provides a method for modulating follicular initiation and fertility by administering to the subject an agent which modulates FOXO3a expression or FOXO3a activity. Subjects at risk for POF, infertility, or a hormone-related disease or disorder, can be identified by, for example, any or a combination of the diagnostic or prognostic assays described herein. Administration of a prophylactic agent can occur prior to the manifestation of symptoms characteristic of aberrant FOXO3a expression or activity, such that POF, infertility, or hormone-related diseases or disorders are prevented or, alternatively, delayed in their progression. Depending on the type of FOXO3a aberrancy, for example, FOXO3a agonist or FOXO3a antagonist agent can be used for treating the subject. Furthermore, a FOXO3a agonist may be used as a contraceptive to modulate, e.g., decrease fertility, temporarily. The appropriate agent can be determined based on screening assays described herein.

B. Therapeutic Methods Described herein are methods and compositions whereby follicular initiation may be modulated, thereby modulating fertility. The present invention provides methods for modulating ovarian follicular initiation in a subject by administering a FOXO3a modulator to either induce or inhibit FOXO3a expression or activity. The present invention also provides methods for modulating fertility in a subject by administering a FOXO3a modulator to either induce or inhibit FOXO3a expression or activity. In one embodiment, FOXO3a expression or activity is increased by administering an inducer or agonist of FOXO3a expression or activity, thereby increasing suppression of ovarian follicular initiation. In this embodiment, the FOXO3a inducer or agonist may be used as a contraceptive as follicular initiation is delayed, while the follicular reserve pool is preserved until the time that fertility is desired. . In an alternative embodiment, FOXO3a expression or activity is reduced or inhibited by administering an inhibitor or antagonist of FOXO3a expression or activity, thereby increasing ovarian follicular initiation, depending on the amount or dosage of the inhibitor or antagonist, or the length of time the inhibitor or antagonist is administered. This increase in follicular initiation may lead to complete depletion of functional ovarian follicles, resulting in infertility in the subject. This embodiment is useful in situations where sterility is desired. In a related embodiment, an inhibitor or antagonist of FOXO3a expression or activity may be used to treat infertility in a subject. In this embodiment, an inhibitor or antagonist of FOXO3a expression or activity is administered to a subject in an amount or dosage sufficient to increase follicular initiation, leading to superovulation, without completely depleting functional ovarian follicles, thereby treating infertility in a subject. In one embodiment, gonadotropins, e.g., leutinizing hormone (LH) or follicular stimulating hormone (FSH), may be administered in combination with the FOXO3a inhibitor, e.g., either sequentially or concurrently, to increase follicular genesis, thereby further treating infertility. Administering a FOXO3a inhibitor or antagonist may also be useful in the procurement of eggs from laboratory animals following superovulation caused by the administration of the FOXO3a antagonist. Accordingly, another aspect of the invention pertains to methods of modulating FOXO3a expression or activity for therapeutic puφoses and for use in contraception. In an exemplary embodiment, the modulatory method of the invention involves contacting a cell with a FOXO3a or agent that modulates one or more of the activities of FOXO3a protein activity associated with the cell (e.g., an ovarian cell). An agent that modulates FOXO3a protein activity can be an agent as described herein, such as a nucleic acid or a protein, an siRNA targeting FOXO3a mRNA, a naturally- occurring target molecule of a FOXO3a protein (e.g., a FOXO3a ligand or substrate), a FOXO3a antibody, a FOXO3a agonist or antagonist, a peptidomimetic of a FOXO3a agonist or antagonist, or other small molecule. In one embodiment, the agent stimulates one or more FOXO3a activities. Examples of such stimulatory agents include active FOXO3a protein, a nucleic acid molecule encoding FOXO3a, or a small molecule agonist, or mimetic, e.g., a peptidomimetic. In another embodiment, the agent inhibits one or more FOXO3a activities. Examples of such inhibitory agents include antisense FOXO3a nucleic acid molecules, siRNAs, antisense nucleic acid molecules, anti- FOXO3a antibodies, small molecules, and FOXO3a inhibitors. These modulatory methods can be performed in vitro (e.g., by culturing the cell with the agent) or, alternatively, in vivo (e.g., by administering the agent to a subject). As such, the present invention provides methods of treating an individual afflicted with a disease or disorder characterized by aberrant or unwanted expression or activity of a FOXO3a protein or nucleic acid molecule. In one embodiment, the method involves administering an agent (e.g., an agent identified by a screening assay described herein), or combination of agents that modulates (e.g., upregulates or downregulates) FOXO3a expression or activity. In another embodiment, the method involves administering a FOXO3a protein or nucleic acid molecule as therapy to compensate for reduced, aberrant, or unwanted FOXO3a expression or activity. Stimulation of FOXO3a activity is desirable in situations in which FOXO3a is abnormally downregulated and/or in which increased FOXO3a activity is likely to have a beneficial effect, e.g., as a contraceptive. Likewise, inhibition of FOXO3a activity is desirable in situations in which FOXO3a is abnormally upregulated and/or in which decreased FOXO3a activity is likely to have a beneficial effect, to effect superovulation as an infertility treatment, e.g., in combination with gonadotropins, or to bring about sterility, e.g., as an alternative to surgical sterilization in a subject.

(i) Methods for Inhibiting Target Gene Expression, Synthesis, or Activity As discussed above, inhibition of FOXO3a expression or activity may be desirable in certain situations. A variety of techniques may be used to inhibit the expression, synthesis, or activity of FOXO3a genes and/or proteins. For example, compounds such as those identified through assays described above, which exhibit inhibitory activity, may be used in accordance with the invention. Such molecules may include, but are not limited to, small organic molecules, siRNAs, peptides, antibodies, and the like. For example, compounds can be administered that compete with endogenous ligand for the FOXO3a protein. The resulting reduction in the amount of ligand-bound FOXO3a protein will modulate endothelial cell physiology. Compounds that can be particularly useful for this puφose include, for example, soluble proteins or peptides, such as peptides comprising one or more of the extracellular domains, or portions and or analogs thereof, of the FOXO3a protein, including, for example, soluble fusion proteins such as Ig-tailed fusion proteins. (For a discussion of the production of Ig-tailed fusion proteins, see, for example, U.S. Pat. No. 5,116,964). Alternatively, compounds, such as ligand analogs or antibodies, that bind to the FOXO3a receptor site, but do not activate the protein, (e.g., receptor-ligand antagonists) can be effective in inhibiting FOXO3a protein activity. Further, antisense and ribozyme molecules and siRNA molecules which inhibit expression of the FOXO3a gene may also be used in accordance with the invention to inhibit aberrant FOXO3a gene activity. Still further, triple helix molecules may be utilized in inhibiting aberrant FOXO3a gene activity. The antisense nucleic acid molecules used in the methods of the invention are typically administered to a subject or generated in situ such that they hybridize with or bind to cellular mRNA and or genomic DNA encoding a FOXO3a protein to thereby inhibit expression of the protein, e.g., by inhibiting transcription and/or translation. The hybridization can be by conventional nucleotide complementarity to form a stable duplex, or, for example, in the case of an antisense nucleic acid molecule which binds to DNA duplexes, through specific interactions in the major groove of the double helix. An example of a route of administration of antisense nucleic acid molecules of the invention include direct injection at a tissue site. Alternatively, antisense nucleic acid molecules can be modified to target selected cells and then administered systemically. For example, for systemic administration, antisense molecules can be modified such that they specifically bind to receptors or antigens expressed on a selected cell surface, e.g., by linking the antisense nucleic acid molecules to peptides or antibodies which bind to cell surface receptors or antigens. The antisense nucleic acid molecules can also be delivered to cells using the vectors described herein. To achieve sufficient intracellular concentrations of the antisense molecules, vector constructs in which the antisense nucleic acid molecule is placed under the control of a strong pol II or pol III promoter are preferred. In yet another embodiment, an antisense nucleic acid molecule used in the methods of the invention is an α-anomeric nucleic acid molecule. An α-anomeric nucleic acid molecule forms specific double-stranded hybrids with complementary RNA in which, contrary to the usual β-units, the strands run parallel to each other (Gaultier et al. (1987) Nucleic Acids. Res. 15:6625-6641). The antisense nucleic acid molecule can also comprise a 2'-o-methylribonucleotide (Inoue et al. (1987) Nucleic Acids Res. 15:6131-6148) or a chimeric RNA-DNA analogue (Inoue et al. (1987) FEBS Lett. 215:327-330). In still another embodiment, an antisense nucleic acid used in the methods of the invention is a ribozyme. Ribozymes are catalytic RNA molecules with ribonuclease activity which are capable of cleaving a single-stranded nucleic acid, such as an mRNA, to which they have a complementary region. Thus, ribozymes (e.g., hammerhead ribozymes (described in Haselhoff and Gerlach (1988) Nature 334:585- 591)) can be used to catalytically cleave FOXO3a mRNA transcripts to thereby inhibit translation of FOXO3a mRNA. A ribozyme having specificity for a FOXO3a-encoding nucleic acid can be designed based upon the nucleotide sequence of a FOXO3a cDNA disclosed herein (i.e., SEQ ID NO:l or 3). For example, a derivative of a Tetrahymena L-19 IVS RNA can be constructed in which the nucleotide sequence of the active site is complementary to the nucleotide sequence to be cleaved in a FOXO3a-encoding mRNA (see, for example, Cech et al. U.S. Patent No. 4,987,071; and Cech et al U.S. Patent No. 5,116,742). Alternatively, FOXO3a mRNA can be used to select a catalytic RNA having a specific ribonuclease activity from a pool of RNA molecules (see, for example, Bartel, D. and Szostak, J.W. (1993) Science 261 : 141 1-1418). FOXO3a gene expression can also be inhibited by targeting nucleotide sequences complementary to the regulatory region of the FOXO3a (e.g., the FOXO3a promoter and/or enhancers) to form triple helical structures that prevent transcription of the FOXO3a gene in target cells (see, for example, Helene, C. (1991) Anticancer Drug Des. 6(6):569-84; Helene, C. et al. (1992) Ann. NY. Acad. Sci. 660:27-36; and Maher, L.J. (1992) Bioassays 14(12):807-15). Antibodies that are both specific for the FOXO3a protein and interfere with its activity may also be used to modulate or inhibit FOXO3a protein function. Such antibodies may be generated using standard techniques described herein, against the FOXO3a protein itself or against peptides conesponding to portions of the protein. Such antibodies include but are not limited to polyclonal, monoclonal, Fab fragments, single chain antibodies, or chimeric antibodies. In instances where the target gene protein is intracellular and whole antibodies are used, internalizing antibodies may be preferred. Lipofectin liposomes may be used to deliver the antibody or a fragment of the Fab region which binds to the target epitope into cells. Where fragments of the antibody are used, the smallest inhibitory fragment which binds to the target protein's binding domain is preferred. For example, peptides having an amino acid sequence corresponding to the domain of the variable region of the antibody that binds to the target gene protein may be used. Such peptides may be synthesized chemically or produced via recombinant DNA technology using methods well known in the art (described in, for example, Creighton (1983), supra; and Sambrook et al. (1989) supra). Single chain neutralizing antibodies which bind to intracellular target gene epitopes may also be administered. Such single chain antibodies may be administered, for example, by expressing nucleotide sequences encoding single-chain antibodies within the target cell population by utilizing, for example, techniques such as those described in Marasco et al. (1993) Proc Natl. Acad. Sci. USA 90:7889-7893).

(ii) Methods for Increasing FOXO3a Expression or Activity for Use in

Contraception Increasing FOXO3a expression or activity leads to increased suppression of follicular initiation by FOXO3a, therefore providing an effective contraceptive while maintaining the follicular reserve pool. A variety of techniques may be used to increase the expression, synthesis, or activity of FOXO3a. Described in this section are methods whereby the level FOXO3a activity may be increased to levels wherein temporary infertility is achieved due to suppression of follicular initiation. The level of FOXO3a activity may be increased, for example, by either increasing the level of FOXO3a gene expression or by increasing the level of active FOXO3a protein which is present.

For example, a FOXO3a protein may be administered to a subject. Any of the techniques discussed below may be used for such administration. One of skill in the art will readily know how to determine the concentration of effective, non-toxic doses of the FOXO3a protein, utilizing techniques such as those described below. Additionally, RNA sequences encoding a FOXO3a protein may be directly administered to a subject, at a concentration sufficient to produce a level of FOXO3a protein such that contraception is effective. Any of the techniques discussed below, which achieve intracellular administration of compounds, such as, for example, liposome administration, may be used for the administration of such RNA molecules. The RNA molecules may be produced, for example, by recombinant techniques such as those described herein. Other contraceptives may be used in combination with the FOXO3a agonists described herein. Further, subjects may be treated by gene replacement therapy, resulting in permanent suppression of follicular initiation and infertility. One or more copies of a FOXO3a gene, or a portion thereof, that directs the production of a normal FOXO3a protein with FOXO3a function, may be inserted into cells using vectors which include, but are not limited to adenovirus, adeno-associated virus, and retrovirus vectors, in addition to other particles that introduce DNA into cells, such as liposomes. Additionally, techniques such as those described above may be used for the introduction of FOXO3a gene sequences into human cells. . Cells, preferably, autologous cells, containing FOXO3a expressing gene sequences may then be introduced or reintroduced into the subject. Such cell replacement techniques may be preferred, for example, when the gene product is a secreted, extracellular gene product.

C. Pharmaceutical Compositions The methods of the invention involve administering to a subject an agent which modulates FOXO3a expression or activity (e.g., an agent identified by a screening assay described herein), or a combination of such agents. In another embodiment, the method involves administering to a subject a FOXO3a protein or nucleic acid molecule as therapy to compensate for reduced, aberrant, or unwanted FOXO3a expression or activity. Stimulation of FOXO3a activity is desirable in situations in which FOXO3a is abnormally downregulated and/or in which increased FOXO3a activity is likely to have a beneficial effect, e.g., as a contraceptive. Likewise, inhibition of

FOXO3a activity is desirable in situations in which FOXO3a is abnormally upregulated and/or in which decreased FOXO3a activity is likely to have a beneficial effect, e.g., to temporarily or permanently increase follicular initiation. The agents which modulate FOXO3a activity can be administered to a subject using pharmaceutical compositions suitable for such administration. Such compositions typically comprise the agent (e.g., nucleic acid molecule, protein, or antibody) and a pharmaceutically acceptable carrier. As used herein the language "pharmaceutically acceptable carrier" is intended to include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absoφtion delaying agents, and the like, compatible with pharmaceutical administration. The use of such media and agents for pharmaceutically active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the active compound, use thereof in the compositions is contemplated. Supplementary active compounds can also be incoφorated into the compositions. A pharmaceutical composition used in the therapeutic methods of the invention is formulated to be compatible with its intended route of administration. Examples of routes of administration include parenteral, e.g., intravenous, intradermal, subcutaneous, oral (e.g., inhalation), transdermal (topical), transmucosal, and rectal administration. Solutions or suspensions used for parenteral, intradermal, or subcutaneous application can include the following components: a sterile diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. pH can be adjusted with acids or bases, such as hydrochloric acid or sodium hydroxide. The parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic. Pharmaceutical compositions suitable for injectable use include sterile aqueous solutions (where water soluble) or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersion. For intravenous administration, suitable carriers include physiological saline, bacteriostatic water, Cremophor EL™ (BASF, Parsippany, NJ) or phosphate buffered saline (PBS). In all cases, the composition must be sterile and should be fluid to the extent that easy syringability exists. It must be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyetheylene glycol, and the like), and suitable mixtures thereof. The proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Prevention of the action of microorganisms can be achieved by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars, polyalcohols such as manitol, sorbitol, and sodium chloride in the composition. Prolonged absoφtion of the injectable compositions can be brought about by including in the composition an agent which delays absoφtion, for example, aluminum monostearate and gelatin. Sterile injectable solutions can be prepared by incoφorating the agent that modulates FOXO3a activity (e.g., a fragment of a FOXO3a protein or an anti- FOXO3a antibody) in the required amount in an appropriate solvent with one or a combination of ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incoφorating the active compound into a sterile vehicle which contains a basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze-drying which yields a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof. Oral compositions generally include an inert diluent or an edible carrier. They can be enclosed in gelatin capsules or compressed into tablets. For the puφose of oral therapeutic administration, the active compound can be incoφorated with excipients and used in the form of tablets, troches, or capsules. Oral compositions can also be prepared using a fluid carrier for use as a mouthwash, wherein the compound in the fluid carrier is applied orally and swished and expectorated or swallowed. Pharmaceutically compatible binding agents, and/or adjuvant materials can be included as part of the composition. The tablets, pills, capsules, troches and the like can contain any of the following ingredients, or compounds of a similar nature: a binder such as microcrystalline cellulose, gum tragacanth or gelatin; an excipient such as starch or lactose, a disintegrating agent such as alginic acid, Primogel, or corn starch; a lubricant such as magnesium stearate or Sterotes; a glidant such as colloidal silicon dioxide; a sweetening. agent such as sucrose or saccharin; or a flavoring agent such as peppermint, methyl salicylate, or orange flavoring. For administration by inhalation, the compounds are delivered in the form of an aerosol spray from pressured container or dispenser which contains a suitable propellant, e.g., a gas such as carbon dioxide, or a nebulizer. Systemic administration can also be by transmucosal or transdermal means. For transmucosal or transdermal administration, penetrants appropriate to the banier to be permeated are used in the formulation. Such penetrants are generally known in the art, and include, for example, for transmucosal administration, detergents, bile salts, and fusidic acid derivatives. Transmucosal administration can be accomplished through the use of nasal sprays or suppositories. For transdermal administration, the active compounds are formulated into ointments, salves, gels, or creams as generally known in the art. The agents that modulate FOXO3a activity can also be prepared in the form of suppositories (e.g., with conventional suppository bases such as cocoa butter and other glycerides) or retention enemas for rectal delivery. In one embodiment, the agents that modulate FOXO3a activity are prepared with carriers that will protect the compound against rapid elimination from the body, such as a controlled release formulation, including implants and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Methods for preparation of such formulations will be apparent to those skilled in the art. The materials can also be obtained commercially from Alza Coφoration and Nova Pharmaceuticals, Inc. Liposomal suspensions (including liposomes targeted to infected cells with monoclonal antibodies to viral antigens) can also be used as pharmaceutically acceptable carriers. These can be prepared according to methods known to those skilled in the art, for example, as described in U.S. Patent No. 4,522,811. It is especially advantageous to formulate oral or parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the subject to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on the unique characteristics of the agent that modulates FOXO3a activity and the particular therapeutic effect to be achieved, and the limitations inherent in the art of compounding such an agent for the treatment of subjects. Toxicity and therapeutic efficacy of such agents can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., for determining the LD50 (the dose lethal to 50% of the population) and the ED50 (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index and can be expressed as the ratio

LD50/ED50. Agents which exhibit large therapeutic indices are preferred. While agents that exhibit toxic side effects may be used, care should be taken to design a delivery system that targets such agents to the site of affected tissue in order to minimize potential damage to uninfected cells and, thereby, reduce side effects. The data obtained from the cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage of such FOXO3a modulating agents lies preferably within a range of circulating concentrations that include the ED50 with little or no toxicity. The dosage may vary within this range depending upon the dosage form employed and the route of administration utilized. For any agent used in the therapeutic methods of the invention, the therapeutically effective dose can be estimated initially from cell culture assays. A dose may be formulated in animal models to achieve a circulating plasma concentration range that includes the IC50 (i.e., the concentration of the test compound which achieves a half-maximal inhibition of symptoms) as determined in cell culture. Such information can be used to more accurately determine useful doses in humans. Levels in plasma may be measured, for example, by high performance liquid chromatography. As defined herein, a therapeutically effective amount of protein or polypeptide (i.e., an effective dosage) ranges from about 0.001 to 30 mg/kg body weight, preferably about 0.01 to 25 mg kg body weight, more preferably about 0.1 to 20 mg/kg body weight, and even more preferably about 1 to 10 mg kg, 2 to 9 mg/kg, 3 to 8 mg kg, 4 to 7 mg/kg, or 5 to 6 mg/kg body weight. The skilled artisan will appreciate that certain factors may influence the dosage required to effectively treat a subject, including but not limited to the severity of the disease or disorder, previous treatments, the general health and/or age of the subject, and other diseases present. Moreover, treatment of a subject with a therapeutically effective amount of a protein, polypeptide, or antibody can include a single treatment or, preferably, can include a series of treatments. In a preferred example, a subject is treated with antibody, protein, or polypeptide in the range of between about 0.1 to 20 mg/kg body weight, one time per week for between about 1 to 10 weeks, preferably between 2 to 8 weeks, more preferably between about 3 to 7 weeks, and even more preferably for about 4, 5, or 6 weeks. It will also be appreciated that the effective dosage of antibody, protein, or polypeptide used for treatment may increase or decrease over the course of a particular treatment. Changes in dosage may result and become apparent from the results of diagnostic assays as described herein. The present invention encompasses agents which modulate expression or activity. An agent may, for example, be a small molecule. For example, such small molecules include, but are not limited to, peptides, peptidomimetics, amino acids, amino acid analogs, polynucleotides, polynucleotide analogs, nucleotides, nucleotide analogs, organic or inorganic compounds (i.e,. including heteroorganic and organometallic compounds) having a molecular weight less than about 10,000 grams per mole, organic or inorganic compounds having a molecular weight less than about 5,000 grams per mole, organic or inorganic compounds having a molecular weight less than about 1,000 grams per mole, organic or inorganic compounds having a molecular weight less than about 500 grams per mole, and salts, esters, and other pharmaceutically acceptable forms of such compounds. It is understood that appropriate doses of small molecule agents depends upon a number of factors within the ken of the ordinarily skilled physician, veterinarian, or researcher. The dose(s) of the small molecule will vary, for example, depending upon the identity, size, and condition of the subject or sample being treated, further depending upon the route by which the composition is to be administered, if applicable, and the effect which the practitioner desires the small molecule to have upon the nucleic acid or polypeptide of the invention. Exemplary doses include milligram or microgram amounts of the small molecule per kilogram of subject or sample weight (e.g., about 1 microgram per kilogram to about 500 milligrams per kilogram, about 100 micrograms per kilogram to about 5 milligrams per kilogram, or about 1 microgram per kilogram to about 50 micrograms per kilogram). It is furthermore understood that appropriate doses of a small molecule depend upon the potency of the small molecule with respect to the expression or activity to be modulated. Such appropriate doses may be determined using the assays described herein. When one or more of these small molecules is to be administered to an animal (e.g., a human) in order to modulate expression or activity of a FOXO3a molecule, a physician, veterinarian, or researcher may, for example, prescribe a relatively low dose at first, subsequently increasing the dose until an appropriate response is obtained. In addition, it is understood that the specific dose level for any particular animal subject will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, gender, and diet of the subject, the time of administration, the route of administration, the rate of excretion, any drug combination, and the degree of expression or activity to be modulated, e.g., the intended use of the agonist or antagonize. With respect to an antagonist, the dose level and length of time administered will depend on the use as a treatment for infertility or as an inducer of sterility, e.g., a larger dose or a dosage given for an extended period of time may be necessary to induce sterility versus a smaller dose or a dosage given over a short term to treat infertility. Further, an antibody (or fragment thereof) may be conjugated to a therapeutic moiety such as a cytotoxin, a therapeutic agent or a radioactive metal ion. A cytotoxin or cytotoxic agent includes any agent that is detrimental to cells. Examples include taxol, cytochalasin B, gramicidin D, ethidium bromide, emetine, mitomycin, etoposide, tenoposide, vincristine, vinblastine, colchicin, doxorubicin, daunorubicin, dihydroxy anthracin dione, mitoxantrone, mithramycin, actinomycin D, 1- dehydrotestosterone, glucocorticoids, procaine, tetracaine, lidocaine, propranolol, and puromycin and analogs or homologs thereof. Therapeutic agents include, but are not limited to, antimetabolites (e.g., methotrexate, 6-mercaptopurine, 6-thioguanine, cytarabine, 5-fluorouracil decarbazine), alkylating agents (e.g., mechlorethamine, thioepa chlorambucil, melphalan, carmustine (BSNU) and lomustine (CCNU), cyclothosphamide, busulfan, dibromomannitol, streptozotocin, mitomycin C, and cis- dichlorodiamine platinum (II) (DDP) cisplatin), anthracyclines (e.g., daunorubicin (formerly daunomycin) and doxorubicin), antibiotics (e.g., dactinomycin (formerly actinomycin), bleomycin, mithramycin, and anthramycin (AMC)), and anti-mitotic agents (e.g., vincristine and vinblastine). The conjugates of the invention can be used for modifying a given biological response, the drug moiety is not to be construed as limited to classical chemical therapeutic agents. For example, the drug moiety may be a protein or polypeptide possessing a desired biological activity. Such proteins may include, for example, a toxin such as abrin, ricin A, pseudomonas exotoxin, or diphtheria toxin; a protein such as tumor necrosis factor, alpha-interferon, beta-interferon, nerve growth factor, platelet derived growth factor, tissue plasminogen activator; or biological response modifiers such as, for example, lymphokines, interleukin-1 ("IL-1"), interleukin-2 ("IL-2"), interleukin-6 ("IL-6"), granulocyte macrophase colony stimulating factor ("GM-CSF"), granulocyte colony stimulating factor ("G-CSF"), or other growth factors. Techniques for conjugating such therapeutic moiety to antibodies are well known, see, e.g., Arnon et al, "Monoclonal Antibodies For Immunotargeting Of Drugs In Cancer Therapy", in Monoclonal Antibodies And Cancer Therapy, Reisfeld et al. (eds.), pp. 243-56 (Alan R. Liss, Inc. 1985); Hellstrom et al, "Antibodies For Drug Delivery", in Controlled Drug Delivery (2nd Ed.), Robinson et al. (eds.), pp. 623-53 (Marcel Dekker, Inc. 1987); Thoφe, "Antibody Caniers Of Cytotoxic Agents In Cancer Therapy: A Review", in Monoclonal Antibodies '84: Biological And Clinical Applications, Pinchera et al. (eds.), pp. 475-506 (1985); "Analysis, Results, And Future Prospective Of The Therapeutic Use Of Radiolabeled Antibody In Cancer Therapy", in Monoclonal Antibodies For Cancer Detection And Therapy, Baldwin et al. (eds.), pp. 303-16 (Academic Press 1985), and Thoφe et al, "The Preparation And Cytotoxic Properties Of Antibody-Toxin Conjugates", Immunol. Rev., 62:119-58 (1982). Alternatively, an antibody can be conjugated to a second antibody to form an antibody heteroconjugate as described by Segal in U.S. Patent No. 4,676,980. The nucleic acid molecules used in the methods of the invention can be inserted into vectors and used as gene therapy vectors. Gene therapy vectors can be delivered to a subject by, for example, intravenous injection, local administration (see U.S. Patent 5,328,470) or by stereotactic injection (see, e.g., Chen et al. (1994) Proc Natl. Acad. Sci. USA 91 :3054-3057). The pharmaceutical preparation of the gene therapy vector can include the gene therapy vector in an acceptable diluent, or can comprise a slow release matrix in which the gene delivery vehicle is imbedded. Alternatively, where the complete gene delivery vector can be produced intact from recombinant cells, e.g., retroviral vectors, the pharmaceutical preparation can include one or more cells which produce the gene delivery system.

IV. Recombinant Expression Vectors and Host Cells Used in the Methods of the Invention The methods of the invention (e.g., the screening assays described herein) include the use of vectors, preferably expression vectors, containing a nucleic acid encoding a FOXO3a protein (or a portion thereof). As used herein, the term "vector" refers to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a "plasmid", which refers to a circular double stranded DNA loop into which additional DNA segments can be ligated. Another type of vector is a viral vector, wherein additional DNA segments can be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as "expression vectors". In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. In the present specification, "plasmid" and "vector" can be used interchangeably as the plasmid is the most commonly used form of vector. However, the invention is intended to include such other forms of expression vectors, such as viral vectors (e.g., replication defective retroviruses, adenoviruses and adeno-associated viruses), which serve equivalent functions. The recombinant expression vectors to be used in the methods of the invention comprise a nucleic acid of the invention in a form suitable for expression of the nucleic acid in a host cell, which means that the recombinant expression vectors include one or more regulatory sequences, selected on the basis of the host cells to be used for expression, which is operatively linked to the nucleic acid sequence to be expressed. Within a recombinant expression vector, "operably linked" is intended to mean that the nucleotide sequence of interest is linked to the regulatory sequence(s) in a manner which allows for expression of the nucleotide sequence (e.g., in an in vitro transcription/translation system or in a host cell when the vector is introduced into the host cell). The term "regulatory sequence" is intended to include promoters, enhancers and other expression control elements (e.g., polyadenylation signals). Such regulatory sequences are described, for example, in Goeddel (1990) Methods Enzymo 185:3-7. Regulatory sequences include those which direct constitutive expression of a nucleotide sequence in many types of host cells and those which direct expression of the nucleotide sequence only in certain host cells (e.g., tissue-specific regulatory sequences). It will be appreciated by those skilled in the art that the design of the expression vector can depend on such factors as the choice of the host cell to be transformed, the level of expression of protein desired, and the like. The expression vectors of the invention can be introduced into host cells to thereby produce proteins or peptides, including fusion proteins or peptides, encoded by nucleic acids as described herein (e.g., FOXO3a proteins, mutant forms of FOXO3a proteins, fusion proteins, and the like). The recombinant expression vectors to be used in the methods of the invention can be designed for expression of FOXO3a proteins in prokaryotic or eukaryotic cells. For example, FOXO3a proteins can be expressed in bacterial cells such as E. coli, insect cells (using baculovirus expression vectors), yeast cells, or mammalian cells. Suitable host cells are discussed further in Goeddel (1990) supra. Alternatively, the recombinant expression vector can be transcribed and translated in vitro, for example using T7 promoter regulatory sequences and T7 polymerase. Expression of proteins in prokaryotes is most often carried out in E. coli with vectors containing constitutive or inducible promoters directing the expression of either fusion or non- fusion proteins. Fusion vectors add a number of amino acids to a protein encoded therein, usually to the amino terminus of the recombinant protein. Such fusion vectors typically serve three puφoses: 1) to increase expression of recombinant protein; 2) to increase the solubility of the recombinant protein; and 3) to aid in the purification of the recombinant protein by acting as a ligand in affinity purification. Often, in fusion expression vectors, a proteolytic cleavage site is introduced at the junction of the fusion moiety and the recombinant protein to enable separation of the recombinant protein from the fusion moiety subsequent to purification of the fusion protein. Such enzymes, and their cognate recognition sequences, include Factor Xa, thrombin and enterokinase. Typical fusion expression vectors include pGEX (Pharmacia Biotech Inc; Smith, D.B. and Johnson, K.S. (1988) Ge«e 67:31-40), pMAL (New England Biolabs, Beverly, MA) and pRIT5 (Pharmacia, Piscataway, NJ) which fuse glutathione S-transferase (GST), maltose E binding protein, or protein A, respectively, to the target recombinant protein. Purified fusion proteins can be utilized in FOXO3a activity assays, (e.g., direct assays or competitive assays described in detail below), or to generate antibodies specific for FOXO3a proteins. In a prefeπed embodiment, a FOXO3a fusion protein expressed in a retroviral expression vector of the present invention can be utilized to infect bone marrow cells which are subsequently transplanted into irradiated recipients. The pathology of the subject recipient is then examined after sufficient time has passed (e.g., six weeks). In another embodiment, a nucleic acid of the invention is expressed in mammalian cells using a mammalian expression vector. Examples of mammalian expression vectors include pCDM8 (Seed, B. (1987) Nature 329:840) and pMT2PC (Kaufman et al. (1987) EMBO J. 6:187-195). When used in mammalian cells, the expression vector's control functions are often provided by viral regulatory elements. For example, commonly used promoters are derived from polyoma, Adenovirus 2, cytomegalovirus and Simian Virus 40. For other suitable expression systems for both prokaryotic and eukaryotic cells see chapters 16 and 17 of Sambrook, J. et al, Molecular Cloning: A Laboratory Manual. 2nd ed., Cold Spring Harbor Laboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 1989. In another embodiment, the recombinant mammalian expression vector is capable of directing expression of the nucleic acid preferentially in a particular cell type (e.g., tissue-specific regulatory elements are used to express the nucleic acid). The methods of the invention may further use a recombinant expression vector comprising a DNA molecule of the invention cloned into the expression vector in an antisense orientation. That is, the DNA molecule is operatively linked to a regulatory sequence in a manner which allows for expression (by transcription of the DNA molecule) of an RNA molecule which is antisense to FOXO3a mRNA. Regulatory sequences operatively linked to a nucleic acid cloned in the antisense orientation can be ' chosen which direct the continuous expression of the antisense RNA molecule in a variety of cell types, for instance viral promoters and/or enhancers, or regulatory sequences can be chosen which direct constitutive, tissue specific, or cell type specific expression of antisense RNA. The antisense expression vector can be in the form of a recombinant plasmid, phagemid, or attenuated virus in which antisense nucleic acids are produced under the control of a high efficiency regulatory region, the activity of which can be determined by the cell type into which the vector is introduced. For a discussion of the regulation of gene expression using antisense genes, see Weintraub, H. et al, Antisense RNA as a molecular tool for genetic analysis, Reviews - Trends in Genetics, Vol. 1(1) 1986. Another aspect of the invention pertains to the use of host cells into which a FOXO3a nucleic acid molecule of the invention is introduced, e.g., a FOXO3a nucleic acid molecule within a recombinant expression vector or a FOXO3a nucleic acid molecule containing sequences which allow it to homologously recombine into a specific site of the host cell's genome. The terms "host cell" and "recombinant host cell" are used interchangeably herein. It is understood that such terms refer not only to the particular subject cell but to the progeny or potential progeny of such a cell. Because certain modifications may occur in succeeding generations due to either mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term as used herein. A host cell can be any prokaryotic or eukaryotic cell. For example, a FOXO3a protein can be expressed in bacterial cells such as E. coli, insect cells, yeast or mammalian cells (such as Chinese hamster ovary cells (CHO) or COS cells). Other suitable host cells are known to those skilled in the art. Vector DNA can be introduced into prokaryotic or eukaryotic cells via conventional transformation or transfection techniques. As used herein, the terms "transformation" and "transfection" are intended to refer to a variety of art-recognized techniques for introducing foreign nucleic acid (e.g., DNA) into a host cell, including calcium phosphate or calcium chloride co-precipitation, DΕAΕ-dextran-mediated transfection, lipofection, or electroporation. Suitable methods for transforming or transfecting host cells can be found in Sambrook et al. (Molecular Cloning: A Laboratory Manual. 2nd, ed., Cold Spring Harbor Laboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 1989), and other laboratory manuals. A host cell used in the methods of the invention, such as a prokaryotic or eukaryotic host cell in culture, can be used to produce (i.e., express) a FOXO3a protein. Accordingly, the invention further provides methods for producing a FOXO3a protein using the host cells of the invention. In one embodiment, the method comprises culturing the host cell of the invention (into which a recombinant expression vector encoding a FOXO3a protein has been introduced) in a suitable medium such that a FOXO3a protein is produced. In another embodiment, the method further comprises isolating a FOXO3a protein from the medium or the host cell.

V. Isolated Nucleic Acid Molecules Used in the Methods of the Invention The nucleotide sequence of the isolated human FOXO3a cDNA and the predicted amino acid sequence of the human FOXO3a polypeptide are shown in SΕQ ID NOs: 1 and 2, respectively, and in Figure 9. The nucleotide sequence of FOXO3a is also described in GenBank Accession No. G 4503738 (SΕQ ID NO: l) (the contents of which are included herein by reference). The methods of the invention include the use of isolated nucleic acid molecules that encode FOXO3a proteins or biologically active portions thereof, as well as nucleic acid fragments sufficient for use as hybridization probes to identify FOXO3a- encoding nucleic acid molecules (e.g., FOXO3a mRNA) and fragments for use as PCR primers for the amplification or mutation of FOXO3a nucleic acid molecules. As used herein, the term "nucleic acid molecule" is intended to include DNA molecules (e.g., cDNA or genomic DNA) and RNA molecules (e.g., mRNA) and analogs of the DNA or RNA generated using nucleotide analogs. The nucleic acid molecule can be single- stranded or double-stranded, but preferably is double-stranded DNA. A nucleic acid molecule used in the methods of the present invention, e.g. , a nucleic acid molecule having the nucleotide sequence of SEQ ID NO: 1 , or a portion thereof, can be isolated using standard molecular biology techniques and the sequence information provided herein. Using all or portion of the nucleic acid sequence of SEQ ID NO:l as a hybridization probe, FOXO3a nucleic acid molecules can be isolated using standard hybridization and cloning techniques (e.g., as described in Sambrook, J., Fritsh, E. F., and Maniatis, T. Molecular Cloning: A Laboratory Manual. 2nd, ed., Cold Spring Harbor Laboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 1989). Moreover, a nucleic acid molecule encompassing all or a portion of SEQ ID NO:l can be isolated by the polymerase chain reaction (PCR) using synthetic oligonucleotide primers designed based upon the sequence of SEQ ID NO: 1. A nucleic acid used in the methods of the invention can be amplified using.cDNA, mRNA or, alternatively, genomic DNA as a template and appropriate oligonucleotide primers according to standard PCR amplification techniques. Furthermore, oligonucleotides corresponding to FOXO3a nucleotide sequences can be prepared by standard synthetic techniques, e.g., using an automated DNA synthesizer. In a preferred embodiment, the isolated nucleic acid molecules used in the methods of the invention comprise the nucleotide sequence shown in SEQ ID NO:l, a complement of the nucleotide sequence shown in SEQ ID NO:l, or a portion of any of these nucleotide sequences. A nucleic acid molecule which is complementary to the nucleotide sequence shown in SEQ ID NO:l, is one which is sufficiently complementary to the nucleotide sequence shown in SEQ ID NO: 1 such that it can hybridize to the nucleotide sequence shown in SEQ ID NO:l thereby forming a stable duplex. In still another preferred embodiment, an isolated nucleic acid molecule used in the methods of the present invention comprises a nucleotide sequence which is at least about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more identical to the entire length of the nucleotide sequence shown in SEQ ID NO:l or a portion of any of this nucleotide sequence. Moreover, the nucleic acid molecules used in the methods of the invention can comprise only a portion of the nucleic acid sequence of SEQ ID NO:l, for example, a fragment which can be used as a probe or primer or a fragment encoding a portion of a FOXO3a protein, e.g., a biologically active portion of a F XO3a protein. The probe/primer typically comprises substantially purified oligonucleotide. The oligonucleotide typically comprises a region of nucleotide sequence that hybridizes under stringent conditions to at least about 12 or 15, preferably about 20 or 25, more preferably about 30, 35, 40, 45, 50, 55, 60, 65, or 75 consecutive nucleotides of a sense sequence of SEQ ID NO:l of an anti-sense sequence of SEQ ID NO:l or of a naturally occurring allelic variant or mutant of SEQ ID NO: 1. In one embodiment, a nucleic acid molecule used in the methods of the present invention comprises a nucleotide sequence which is greater than 100, 100-200, 200-300, 300-400, 400-500, 500-600, 600-700, 700- 800, 800-900, 900-1000, 1000-1100, 1 100-1200, 1200-1300, or more nucleotides in length and hybridizes under stringent hybridization conditions to a nucleic acid molecule of SEQ ID NO:l. As used herein, the term "hybridizes under stringent conditions" is intended to describe conditions for hybridization and washing under which nucleotide sequences that are significantly identical or homologous to each other remain hybridized to each other. Preferably, the conditions are such that sequences at least about 70%, more preferably at least about 80%, even more preferably at least about 85% or 90% identical to each other remain hybridized to each other. Such stringent conditions are known to those skilled in the art and can be found in Current Protocols in Molecular Biology, Ausubel et al, eds., John Wiley & Sons, Inc. (1995), sections 2, 4 and 6. Additional stringent conditions can be found in Molecular Cloning: A Laboratory Manual, Sambrook et al, Cold Spring Harbor Press, Cold Spring Harbor, NY (1989), chapters 7, 9 and 11. A preferred, non-limiting example of stringent hybridization conditions includes hybridization in 4X sodium chloride/sodium citrate (SSC), at about 65-70°C (or hybridization in 4X SSC plus 50% formamide at about 42- 50°C) followed by one or more washes in IX SSC, at about 65-70°C. A preferred, non- limiting example of highly stringent hybridization conditions includes hybridization in IX SSC, at about 65-70°C (or hybridization in IX SSC plus 50% formamide at about 42-50°C) followed by one or more washes in 0.3X SSC, at about 65-70°C. A preferred, non-limiting example of reduced stringency hybridization conditions includes hybridization in 4X SSC, at about 50-60°C (or alternatively hybridization in 6X SSC plus 50% formamide at about 40-45°C) followed by one or more washes in 2X SSC, at about 50-60°C. Ranges intermediate to the above-recited values, e.g., at 65-70°C or at 42-50°C are also intended to be encompassed by the present invention. SSPE (lxSSPE is 0.15M NaCl, lOmM NaH₂PO₄, and 1.25mM EDTA, pH 7.4) can be substituted for SSC (lxSSC is 0.15M NaCl and 15mM sodium citrate) in the hybridization and wash buffers; washes are performed for 15 minutes each after hybridization is complete. The hybridization temperature for hybrids anticipated to be less than 50 base pairs in length should be 5-10°C less than the melting temperature (T_m) of the hybrid, where T_m is determined according to the following equations. For hybrids less than 18 base pairs in length, T_m(°C) = 2(# of A + T bases) + 4(# of G + C bases). For hybrids between 18 and 49 base pairs in length, T_m(°C) = 81.5 + 16.6(log₁₀[Na⁺]) + 0.41(%G+C) - (600/N), where N is the number of bases in the hybrid, and [Na⁺] is the concentration of sodium ions in the hybridization buffer ([Na⁺] for lxSSC - 0.165 M). It will also be recognized by the skilled practitioner that additional reagents may be added to hybridization and/or wash buffers to decrease non-specific hybridization of nucleic acid molecules to membranes, for example, nitrocellulose or nylon membranes, including but not limited to blocking agents (e.g., BSA or salmon or herring sperm carrier DNA), detergents (e.g., SDS), chelating agents (e.g., EDTA), Ficoll, PVP and the like. When using nylon membranes, in particular, an additional preferred, non-limiting example of stringent hybridization conditions is hybridization in 0.25-0.5M NaH₂PO₄, 7% SDS at about 65°C, followed by one or more washes at 0.02M NaH₂PO₄, 1% SDS at 65°C, see e.g., Church and Gilbert (1984) Proc. Natl. Acad. Sci. USA 81 :1991-1995, (or alternatively 0.2X SSC, 1% SDS). In preferred embodiments, the probe further comprises a label group attached thereto, e.g. , the label group can be a radioisotope, a fluorescent compound, an enzyme, or an enzyme co-factor. Such probes can be used as a part of a diagnostic test kit for identifying cells or tissue which misexpress a FOXO3a protein, such as by measuring a level of a FOXO3a-encoding nucleic acid in a sample of cells from a subject e.g., detecting FOXO3a mRNA levels or determining whether a genomic FOXO3a gene has been mutated or deleted. The methods of the invention further encompass the use of nucleic acid molecules that differ from the nucleotide sequence shown in SEQ ID NO: 1 due to degeneracy of the genetic code and thus encode the same FOXO3a proteins as those encoded by the nucleotide sequence shown in SEQ ID NO: 1. In another embodiment, an isolated nucleic acid molecule included in the methods of the invention has a nucleotide sequence encoding a protein having an amino acid sequence shown in SEQ ID NO:2. The methods of the invention further include the use of allelic variants of human FOXO3a, e.g., functional and non- functional allelic variants. Functional allelic variants are naturally occurring amino acid sequence variants of the human FOXO3a protein that maintain a FOXO3a activity. Functional allelic variants will typically contain only conservative substitution of one or more amino acids of SEQ ID NO:2, or substitution, deletion or insertion of non-critical residues in non-critical regions of the protein. Non-functional allelic variants are naturally occwring amino acid sequence variants of the human FOXO3a protein that do not have a FOXO3a activity. Non-functional allelic variants will typically contain a non-conservative substitution, deletion, or insertion or premature truncation of the amino acid sequence of SEQ ID NO:2, or a substitution, insertion or deletion in critical residues or critical regions of the protein. The methods of the present invention may further use non-human orthologues of the human FOXO3a protein. Orthologues of the human FOXO3a protein are proteins that are isolated from non-human organisms and possess the same FOXO3a activity. The methods of the present invention further include the use of nucleic acid molecules comprising the nucleotide sequence of SEQ ID NO:l or a portion thereof, in which a mutation has been introduced. The mutation may lead to amino acid substitutions at "non-essential" amino acid residues or at "essential" amino acid residues. A "non-essential" amino acid residue is a residue that can be altered from the wild-type sequence of FOXO3a (e.g., the sequence of SEQ ID NO:2) without altering the biological activity, whereas an "essential" amino acid residue is required for biological activity. For example, amino acid residues that are conserved among the FOXO3a proteins of the present invention and other members of the FOXO family are not likely to be amenable to alteration. Mutations can be introduced into SEQ ID NO:l by standard techniques, such as site-directed mutagenesis and PCR-mediated mutagenesis. Preferably, conservative amino acid substitutions are made at one or more predicted non-essential amino acid residues. A "conservative amino acid substitution" is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Thus, a predicted nonessential amino acid residue in a FOXO3a protein is preferably replaced with another amino acid residue from the same side chain family. Alternatively, in another embodiment, mutations can be introduced randomly along all or part of a FOXO3a coding sequence, such as by saturation mutagenesis, and the resultant mutants can be screened for FOXO3a biological activity to identify mutants that retain activity. Following mutagenesis of SEQ ID NO:l the encoded protein can be expressed recombinantly and the activity of the protein can be determined using the assay described herein. Another aspect of the invention pertains to the use of isolated nucleic acid molecules which are antisense to the nucleotide sequence of SEQ ID NO: 1. An "antisense" nucleic acid comprises a nucleotide sequence which is complementary to a "sense" nucleic acid encoding a protein, e.g., complementary to the coding strand of a double-stranded cDNA molecule or complementary to an mRNA sequence. Accordingly, an antisense nucleic acid can hydrogen bond to a sense nucleic acid. The antisense nucleic acid can be complementary to an entire FOXO3a coding strand, or to only a portion thereof. In one embodiment, an antisense nucleic acid molecule is antisense to a "coding region" of the coding strand of a nucleotide sequence encoding a FOXO3a. The term "coding region" refers to the region of the nucleotide sequence comprising codons which are translated into amino acid residues. In another embodiment, the antisense nucleic acid molecule is antisense to a "noncoding region" of the coding strand of a nucleotide sequence encoding FOXO3a. The term "noncoding region" refers to 5' and 3' sequences which flank the coding region that are not translated into amino acids (also referred to as 5' and 3' untranslated regions). Given the coding strand sequences encoding FOXO3a disclosed herein, antisense nucleic acids of the invention can be designed according to the rules of Watson and Crick base pairing. The antisense nucleic acid molecule can be complementary to the entire coding region of FOXO3a mRNA, but more preferably is an oligonucleotide which is antisense to only a portion of the coding or noncoding region of FOXO3a mRNA. For example, the antisense oligonucleotide can be complementary to the region surrounding the translation start site of FOXO3a mRNA. An antisense oligonucleotide can be, for example, about 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 nucleotides in length. An antisense nucleic acid of the invention can be constructed using chemical synthesis and enzymatic ligation reactions using procedures known in the art. For example, an antisense nucleic acid (e.g., an antisense oligonucleotide) can be chemically synthesized using naturally occurring nucleotides or variously modified nucleotides designed to increase the biological stability of the molecules or to increase the physical stability of the duplex formed between the antisense and sense nucleic acids, e.g., phosphorothioate derivatives and acridine substituted nucleotides can be used. Examples of modified nucleotides which can be used to generate the antisense nucleic acid include 5- fluorouracil, 5-bromouracil, 5-chlorouracil, 5-iodouracil, hypoxanthine, xantine, 4- acetylcytosine, 5-(carboxyhydroxylmethyl) uracil, 5-carboxymethylaminomethyl-2- thiouridine, 5-carboxymethylaminomethyluracil, dihydrouracil, beta-D- galactosylqueosine, inosine, N6-isopentenyladenine, 1 -methyl guanine, 1-methylinosine, 2,2-dimethylguanine, 2-methyladenine, 2-methylguanine, 3-methylcytosine, 5- methylcytosine, N6-adenine, 7-methylguanine, 5-methylaminomethyluracil, 5- methoxyaminomethyl-2-thiouracil, beta-D-mannosylqueosine, 5'- methoxycarboxymethyluracil, 5-methoxyuracil, 2-methylthio-N6-isopentenyladenine, uracil-5-oxyacetic acid (v), wybutoxosine, pseudouracil, queosine, 2-thiocytosine, 5- methyl-2-thiouracil, 2-thiouracil, 4-thiouracil, 5-methyluracil, uracil-5- oxyacetic acid methylester, uracil-5-oxyacetic acid (v), 5-methyl-2-thiouracil, 3-(3-amino-3-N-2- carboxypropyl) uracil, (acp3)w, and 2,6-diaminopurine. Alternatively, the antisense nucleic acid can be produced biologically using an expression vector into which a nucleic acid has been subcloned in an antisense orientation (i.e., RNA transcribed from the inserted nucleic acid will be of an antisense orientation to a target nucleic acid of interest). Antisense nucleic acid molecules used in the methods of the invention are further described above, in section IV. In yet another embodiment, the FOXO3a nucleic acid molecules used in the methods of the present invention can be modified at the base moiety, sugar moiety or phosphate backbone to improve, e.g., the stability, hybridization, or solubility of the molecule. For example, the deoxyribose phosphate backbone of the nucleic acid molecules can be modified to generate peptide nucleic acids (see Hyrup B. et al (1996) Bioorganic & Medicinal Chemistry 4 (1): 5-23). As used herein, the terms "peptide nucleic acids" or "PNAs" refer to nucleic acid mimics, e.g. , DNA mimics, in which the deoxyribose phosphate backbone is replaced by a pseudopeptide backbone and only the four natural nucleobases are retained. The neutral backbone of PNAs has been shown to allow for specific hybridization to DNA and RNA under conditions of low ionic strength. The synthesis of PNA oligomers can be performed using standard solid phase peptide synthesis protocols as described in Hyrup B. et al. (1996) supra; Perry-O'Keefe et al. (1996) Proc. Natl. Acad. Sci. 93:14670-675. PNAs of FOXO3a nucleic acid molecules can be used in the therapeutic and diagnostic applications described herein. For example, PNAs can be used as antisense or antigene agents for sequence-specific modulation of gene expression by, for example, inducing transcription or translation anest or inhibiting replication. PNAs of FOXO3a nucleic acid molecules can also be used in the analysis of single base pair mutations in a gene, (e.g., by PNA-directed PCR clamping); as 'artificial restriction enzymes' when used in combination with other enzymes, (e.g., SI nucleases (Hyrup B. et al. (1996) supra)); or as probes or primers for DNA sequencing or hybridization (Hyrup B. et al. (1996) supra; Perry-O'Keefe et al (1996) supra). In another embodiment, PNAs of FOXO3a can be modified, (e.g., to enhance their stability or cellular uptake), by attaching lipophilic or other helper groups to PNA, by the formation of PNA-DNA chimeras, or by the use of liposomes or other techniques of drug delivery known in the art. For example, PNA-DNA chimeras of FOXO3a nucleic acid molecules can be generated which may combine the advantageous properties of PNA and DNA. Such chimeras allow DNA recognition enzymes, (e.g., RNAse H and DNA polymerases), to interact with the DNA portion while the PNA portion would provide high binding affinity and specificity. PNA-DNA chimeras can be linked using linkers of appropriate lengths selected in terms of base stacking, number of bonds between the nucleobases, and orientation (Hyrup B. et al. (1996) supra). The synthesis of PNA-DNA chimeras can be performed as described in Hyrup B. et al. (1996) supra and Finn P.J. et al. (1996) Nucleic Acids Res. 24 (17): 3357-63. For example, a DNA chain can be synthesized on a solid support using standard phosphoramidite coupling chemistry and modified nucleoside analogs, e.g., 5'-(4- methoxytrityl)aτnino-5'-deoxy-thymidine phosphoramidite, can be used as a between the PNA and the 5' end of DNA (Mag, M. et al. (1989) Nucleic Acid Res. 17: 5973-88). PNA monomers are then coupled in a stepwise manner to produce a chimeric molecule with a 5' PNA segment and a 3' DNA segment (Finn P.J. et al. (1996) supra).

Alternatively, chimeric molecules can be synthesized with a 5' DNA segment and a 3' PNA segment (Peterser, K.H. et al. (1975) Bioorganic Med. Chem. Lett. 5: 1119-11 124). In other embodiments, the oligonucleotide used in the methods of the invention may include other appended groups such as peptides (e.g., for targeting host cell receptors in vivo), or agents facilitating transport across the cell membrane (see, e.g., Letsinger et al. (1989) Proc. Natl. Acad. Sci. USA 86:6553-6556; Lemaitre et al. (1987) Proc. Natl. Acad. Sci. USA 84:648-652; PCT Publication No. W088/09810) or the blood-brain barrier (see, e.g., PCT Publication No. W089/10134). In addition, oligonucleotides can be modified with hybridization-triggered cleavage agents (See, e.g., Krol et al. (1988) Bio-Techniques 6:958-976) or intercalating agents. (See, e.g., Zon (1988) Pharm. Res. 5:539-549). To this end, the oligonucleotide maybe conjugated to another molecule, (e.g., a peptide, hybridization triggered cross-linking agent, transport agent, or hybridization-triggered cleavage agent). VI. Isolated FOXO3a Proteins and Anti-FOXO3a Antibodies Used in the Methods of the Invention The methods of the invention include the use of isolated FOXO3a proteins, and biologically active portions thereof, as well as polypeptide fragments suitable for use as immunogens to raise anti-FOXO3a antibodies. In one embodiment, native FOXO3 proteins can be isolated from cells or tissue sources by an appropriate purification scheme using standard protein purification techniques. In another embodiment, FOXO3a proteins are produced by recombinant DNA techniques. Alternative to recombinant expression, a FOXO3a protein or polypeptide can be synthesized chemically using standard peptide synthesis techniques. As used herein, a "biologically active portion" of a FOXO3a protein includes a fragment of a FOXO3a protein having a FOXO3a activity. Biologically active portions of a FOXO3a protein include peptides comprising amino acid sequences sufficiently identical to or derived from the amino acid sequence of the FOXO3a protein, e.g., the amino acid sequence shown in SEQ ID NO:2, which include fewer amino acids than the full length FOXO3a proteins, and exhibit at least one activity of a FOXO3a protein. Typically, biologically active portions comprise a domain or motif with at least one activity of the FOXO3a protein (e.g., the N-terminal region of the FOXO3a protein that is believed to be involved in the regulation of apoptotic activity). A biologically active portion of a FOXO3a protein can be a polypeptide which is, for example, 25, 50, 75, 100, 125, 150, 175, 200, 250, 300 or more amino acids in length. Biologically active portions of a FOXO3a protein can be used as targets for developing agents which modulate a FOXO3a activity. In a preferred embodiment, the FOXO3a protein used in the methods of the invention has an amino acid sequence shown in SEQ ID NO:2. In other embodiments, the FOXO3a protein is substantially identical to SEQ ED NO:2, and retains the functional activity of the protein of SEQ ID NO:2, yet differs in amino acid sequence due to natural allelic variation or mutagenesis, as described in detail in subsection V above. Accordingly, in another embodiment, the FOXO3a protein used in the methods of the invention is a protein which comprises an amino acid sequence at least about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO:2. To determine the percent identity of two amino acid sequences or of two nucleic acid sequences, the sequences are aligned for optimal comparison puφoses (e.g., gaps can be introduced in one or both of a first and a second amino acid or nucleic acid sequence for optimal alignment and non-identical sequences can be disregarded for comparison puφoses). In a preferred embodiment, the length of a reference sequence aligned for comparison puφoses is at least 30%, preferably at least 40%, more preferably at least 50%, even more preferably at least 60%, and even more preferably at least 70%, 80%, or 90%> of the length of the reference sequence (e.g., when aligning a second sequence to the FOXO3a amino acid sequence of SEQ ID NO:2 having 500 amino acid residues, at least 75, preferably at least 150, more preferably at least 225, even more preferably at least 300, and even more preferably at least 400 or more amino acid residues are aligned). The amino acid residues or nucleotides at conesponding amino acid positions or nucleotide positions are then compared. When a position in the first sequence is occupied by the same amino acid residue or nucleotide as the corresponding position in the second sequence, then the molecules are identical at that position (as used herein amino acid or nucleic acid "identity" is equivalent to amino acid or nucleic acid "homology"). The percent identity between the two sequences is a function of the number of identical positions shared by the sequences, taking into account the number of gaps, and the length of each gap, which need to be introduced for optimal alignment of the two sequences. The comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematical algorithm. In a preferred embodiment, the percent identity between two amino acid sequences is determined using the Needleman and Wunsch (J. Mol. Biol. 48:444-453 (1970)) algorithm which has been incoφorated into the GAP program in the GCG software package (available at http://www.gcg.com), using either a Blosum 62 matrix or a PAM250 matrix, and a gap weight of 16, 14, 12, 10, 8, 6, or 4 and a length weight of 1, 2, 3, 4, 5, or 6. In yet another preferred embodiment, the percent identity between two nucleotide sequences is determined using the GAP program in the GCG software package (available at http://www.gcg.com), using a NWSgapdna.CMP matrix and a gap weight of 40, 50, 60, 70, or 80 and a length weight of 1, 2, 3, 4, 5, or 6. In another embodiment, the percent identity between two amino acid or nucleotide sequences is determined using the algorithm of E. Meyers and W. Miller (Comput. Appl Biosci. 4:11- 17 (1988)) which has been incoφorated into the ALIGN program (version 2.0 or 2.0U), using a PAM120 weight residue table, a gap length penalty of 12 and a gap penalty of 4. The methods of the invention may also use FOXO3a chimeric or fusion proteins. As used herein, a FOXO3a "chimeric protein" or "fusion protein" comprises a FOXO3a polypeptide operatively linked to a non-FOXO3a polypeptide. An "FOXO3a polypeptide" refers to a polypeptide having an amino acid sequence corresponding to a FOXO3a molecule, whereas a "non-FOXO3a polypeptide" refers to a polypeptide having an amino acid sequence corresponding to a protein which is not substantially homologous to the FOXO3a protein, e.g., a protein which is different from the FOXO3a protein and which is derived from the same or a different organism. Within a FOXO3a fusion protein the FOXO3a polypeptide can correspond to all or a portion of a FOXO3a protein. In a preferred embodiment, a FOXO3a fusion protein comprises at least one biologically active portion of a FOXO3a protein. In another preferred embodiment, a FOXO3a fusion protein comprises at least two biologically active portions of a FOXO3a protein. Within the fusion protein, the term "operatively linked" is intended to indicate that the FOXO3a polypeptide and the non-FOXO3a polypeptide are fused in-frame to each other. The non-FOXO3a polypeptide can be fused to the N-terminus or C-terminus of the FOXO3a polypeptide. For example, in one embodiment, the fusion protein is a GST-FOXO3a fusion protein in which the FOXO3a sequences are fused to the C-terminus of the GST sequences. Such fusion proteins can facilitate the purification of recombinant FOXO3a. In another embodiment, this fusion protein is a FOXO3a protein containing a heterologous signal sequence at its N-terminus. In certain host cells (e.g., mammalian host cells), expression and/or secretion of FOXO3a can be increased through use of a heterologous signal sequence. The FOXO3a fusion proteins used in the methods of the invention can be incoφorated into pharmaceutical compositions and administered to a subject in vivo. The FOXO3a fusion proteins can be used to affect the bioavailability of a FOXO3a substrate. Use of FOXO3a fusion proteins may be useful therapeutically for the treatment of disorders caused by, for example, (i) aberrant modification or mutation of a gene encoding a FOXO3a protein; (ii) mis-regulation of the FOXO3a gene; and (iii) aberrant post-translational modification of a FOXO3a protein. Moreover, the FOXO3 a- fusion proteins used in the methods of the invention can be used as immunogens to produce anti-FOXO3a antibodies in a subject, to purify FOXO3a ligands and in screening assays to identify molecules which inhibit the interaction of FOXO3a with a FOXO3a substrate. Preferably, a FOXO3a chimeric or fusion protein used in the methods of the invention is produced by standard recombinant DNA techniques. For example, DNA fragments coding for the different polypeptide sequences are ligated together in- frame in accordance with conventional techniques, for example by employing blunt- ended or stagger-ended termini for ligation, restriction enzyme digestion to provide for appropriate termini, filling-in of cohesive ends as appropriate, alkaline phosphatase treatment to avoid undesirable joining, and enzymatic ligation. In another embodiment, the fusion gene can be synthesized by conventional techniques including automated DNA synthesizers. Alternatively, PCR amplification of gene fragments can be carried out using anchor primers which give rise to complementary overhangs between two consecutive gene fragments which can subsequently be annealed and reamplified to generate a chimeric gene sequence (see, for example, Current Protocols in Molecular Biology, eds. Ausubel et al. John Wiley & Sons: 1992). Moreover, many expression vectors are commercially available that already encode a fusion moiety (e.g., a GST polypeptide). A FOXO3a-encoding nucleic acid can be cloned into such an expression vector such that the fusion moiety is linked in-frame to the FOXO3a protein. The present invention also pertains to the use of variants of the FOXO3a proteins which function as either FOXO3a agonists (mimetics) or as FOXO3a antagonists. Variants of the FOXO3a proteins can be generated by mutagenesis, e.g., discrete point mutation or truncation of a FOXO3a protein. An agonist of the FOXO3a proteins can retain substantially the same, or a subset, of the biological activities of the naturally occurring form of a FOXO3a protein. An antagonist of a FOXO3a protein can inhibit one or more of the activities of the naturally occurring form of the FOXO3a protein by, for example, competitively modulating a FOXO3a-mediated activity of a FOXO3a protein. Thus, specific biological effects can be elicited by treatment with a variant of limited function. In one embodiment, treatment of a subject with a variant having a subset of the biological activities of the naturally occurring form of the protein has fewer side effects in a subject relative to treatment with the naturally occurring form of the FOXO3a protein. In one embodiment, variants of a FOXO3a protein which function as either FOXO3a agonists (mimetics) or as FOXO3a antagonists can be identified by screening combinatorial libraries of mutants, e.g., truncation mutants, of a FOXO3a protein for FOXO3a protein agonist or antagonist activity. In one embodiment, a variegated library of FOXO3a variants is generated by combinatorial mutagenesis at the nucleic acid level and is encoded by a variegated gene library. A variegated library of FOXO3a variants can be produced by, for example, enzymatically ligating a mixture of synthetic oligonucleotides into gene sequences such that a degenerate set of potential

FOXO3a sequences is expressible as individual polypeptides, or alternatively, as a set of larger fusion proteins (e.g., for phage display) containing the set of FOXO3a sequences therein. There are a variety of methods which can be used to produce libraries of potential FOXO3a variants from a degenerate oligonucleotide sequence. Chemical synthesis of a degenerate gene sequence can be performed in an automatic DNA synthesizer, and the synthetic gene then ligated into an appropriate expression vector. Use of a degenerate set of genes allows for the provision, in one mixture, of all of the sequences encoding the desired set of potential FOXO3a sequences. Methods for synthesizing degenerate oligonucleotides are known in the art (see, e.g., Narang, S.A. (1983) Tetrahedron 39:3; Itakura et al. (1984) Annu. Rev. Biochem. 53:323; Itakura et al. (1984) Science 198:1056; Ike et al. (1983) Nucleic Acid Res. 11 :477). In addition, libraries of fragments of a FOXO3a protein coding sequence can be used to generate a variegated population of FOXO3a fragments for screening and subsequent selection of variants of a FOXO3a protein. In one embodiment, a library of coding sequence fragments can be generated by treating a double stranded PCR fragment of a FOXO3a coding sequence with a nuclease under conditions wherein nicking occurs only about once per molecule, denaturing the double stranded DNA, renaturing the DNA to form double stranded DNA which can include sense/antisense pairs from different nicked products, removing single stranded portions from reformed duplexes by treatment with SI nuclease, and ligating the resulting fragment library into an expression vector. By this method, an expression library can be derived which encodes N-terminal, C-terminal and internal fragments of various sizes of the FOXO3a protein. Several techniques are known in the art for screening gene products of combinatorial libraries made by point mutations or truncation, and for screening cDNA libraries for gene products having a selected property. Such techniques are adaptable for rapid screening of the gene libraries generated by the combinatorial mutagenesis of FOXO3a proteins. The most widely used techniques, which are amenable to high through-put analysis, for screening large gene libraries typically include cloning the gene library into replicable expression vectors, transforming appropriate cells with the resulting library of vectors, and expressing the combinatorial genes under conditions in which detection of a desired activity facilitates isolation of the vector encoding the gene whose product was detected. Recursive ensemble mutagenesis (REM), a new technique which enhances the frequency of functional mutants in the libraries, can be used in combination with the screening assays to identify FOXO3a variants (Arkin and Yourvan (1992) Proc. Natl. Acad. Sci. USA 89:7811-7815; Delgrave et al. (1993) Protein Engineering 6(3):327-331). The methods of the present invention further include the use of anti-

FOXO3a antibodies. An isolated FOXO3a protein, or a portion or fragment thereof, can be used as an immunogen to generate antibodies that bind FOXO3a using standard techniques for polyclonal and monoclonal antibody preparation. A full-length FOXO3a protein can be used or, alternatively, antigenic peptide fragments of FOXO3a can be used as immunogens. The antigenic peptide of FOXO3a comprises at least 8 amino acid residues of the amino acid sequence shown in SEQ ID NO:2 and encompasses an epitope of FOXO3a such that an antibody raised against the peptide forms a specific immune complex with the FOXO3a protein. Preferably, the antigenic peptide comprises at least 10 amino acid residues, more preferably at least 15 amino acid residues, even more preferably at least 20 amino acid residues, and most preferably at least 30 amino acid residues. Preferred epitopes encompassed by the antigenic peptide are regions of FOXO3a that are located on the surface of the protein, e.g., hydrophihc regions, as well as regions with high antigenicity. A FOXO3a immunogen is typically used to prepare antibodies by immunizing a suitable subject, (e.g., rabbit, goat, mouse, or other mammal) with the immunogen. An appropriate immunogenic preparation can contain, for example, recombinantly expressed FOXO3a protein or a chemically synthesized FOXO3a polypeptide. The preparation can further include an adjuvant, such as Freund's complete or incomplete adjuvant, or similar immunostimulatory agent. Immunization of a suitable subject with an immunogenic FOXO3a preparation induces a polyclonal anti-FOXO3a antibody response. The term "antibody" as used herein refers to immunoglobulin molecules and immuno logically active portions of immunoglobulin molecules, i.e., molecules that contain an antigen binding site which specifically binds (immunoreacts with) an antigen, such as a FOXO3a. Examples of immunologically active portions of immunoglobulin molecules include F(ab) and F(ab')₂ fragments which can be generated by treating the antibody with an enzyme such as pepsin. The invention provides polyclonal and monoclonal antibodies that bind FOXO3a molecules. The term "monoclonal antibody" or "monoclonal antibody composition", as used herein, refers to a population of antibody molecules that contain only one species of an antigen binding site capable of immunoreacting with a particular epitope of FOXO3a. A monoclonal antibody composition thus typically displays a single binding affinity for a particular FOXO3a protein with which it immunoreacts. Polyclonal anti-FOXO3a antibodies can be prepared as described above by immunizing a suitable subject with a FOXO3a immunogen. The anti-FOXO3a antibody titer in the immunized subject can be monitored over time by standard techniques, such as with an enzyme linked immunosorbent assay (ELISA) using immobilized FOXO3a. If desired, the antibody molecules directed against FOXO3a can be isolated from the mammal (e.g., from the blood) and further purified by well known techniques, such as protein A chromatography to obtain the IgG fraction. At an appropriate time after immunization, e.g., when the anti-FOXO3a antibody titers are highest, antibody-producing cells can be obtained from the subject and used to prepare monoclonal antibodies by standard techniques, such as the hybridoma technique originally described by Kohler and Milstein (1975) Nature 256:495-497) (see also, Brown et al (1981) J. Immunol. 127:539-46; Brown et al. (1980) J. Biol. Chem. 255:4980-83; Yeh et al. (1976) Proc Natl. Acad. Sci. USA 76:2927-31; and Yeh et al. (1982) Int. J. Cancer 29:269-75), the more recent human B cell hybridoma technique (Kozbor et al. (1983) Immunol Today 4:72), the EBV-hybridoma technique (Cole et al. (1985) Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp. 77-96) or trioma techniques. The technology for producing monoclonal antibody hybridomas is well known (see generally Kenneth, R. H. in Monoclonal Antibodies: A New Dimension In Biological Analyses, Plenum Publishing Coφ., New York, New York (1980); Lerner, E. A. (1981) YaleJ. Biol. Med. 54:387-402; Gefter, M. L. et al. (1977) Somatic Cell Genet. 3:231-36). Briefly, an immortal cell line (typically a myeloma) is fused to lymphocytes (typically splenocytes) from a mammal immunized with a FOXO3a immunogen as described above, and the culture supernatants of the resulting hybridoma cells are screened to identify a hybridoma producing a monoclonal antibody that binds FOXO3a. Any of the many well known protocols used for fusing lymphocytes and immortalized cell lines can be applied for the puφose of generating an anti-FOXO3a monoclonal antibody (see, e.g., G. Galfre et al. (1977) Nature 266:55052; Gefter et al. (1977) supra; Lerner (1981) supra; and Kenneth (1980) supra). Moreover, the ordinarily skilled worker will appreciate that there are many variations of such methods which also would be useful. Typically, the immortal cell line (e.g., a myeloma cell line) is derived from the same mammalian species as the lymphocytes. For example, murine hybridomas can be made by fusing lymphocytes from a mouse immunized with an immunogenic preparation of the present invention with an immortalized mouse cell line. Prefened immortal cell lines are mouse myeloma cell lines that are sensitive to culture medium containing hypoxanthine, aminopterin and thymidine ("HAT medium"). Any of a number of myeloma cell lines can be used as a fusion partner according to standard techniques, e.g., the P3-NSl/l-Ag4-l, P3-x63-Ag8.653 or Sp2/O-Agl4 myeloma lines. These myeloma lines are available from ATCC. Typically, HAT-sensitive mouse myeloma cells are fused to mouse splenocytes using polyethylene glycol ("PEG"). Hybridoma cells resulting from the fusion are then selected using HAT medium, which kills unfused and unproductively fused myeloma cells (unfused splenocytes die after several days because they are not transformed). Hybridoma cells producing a monoclonal antibody of the invention are detected by screening the hybridoma culture supernatants for antibodies that bind FOXO3a, e.g., using a standard ELISA assay. Alternative to preparing monoclonal antibody-secreting hybridomas, a monoclonal anti-FOXO3a antibody can be identified and isolated by screening a recombinant combinatorial immunoglobulin library (e.g., an antibody phage display library) with FOXO3a to thereby isolate immunoglobulin library members that bind FOXO3a. Kits for generating and screening phage display libraries are commercially available (e.g., the Pharmacia Recombinant Phage Antibody System, Catalog No. 27- 9400-01; and the Stratagene SurfZAP™ Phage Display Kit, Catalog No. 240612). Additionally, examples of methods and reagents particularly amenable for use in generating and screening antibody display library can be found in, for example, Ladner et al. U.S. Patent No. 5,223,409; Kang et al. PCT International Publication No. WO 92/18619; Dower et al. PCT International Publication No. WO 91/17271; Winter et al PCT International Publication WO 92/20791 ; Markland et al. PCT International Publication No. WO 92/15679; Breitling et al. PCT International Publication WO 93/01288; McCafferty et al. PCT International Publication No. WO 92/01047; Garrard et al. PCT International Publication No. WO 92/09690; Ladner et al. PCT International Publication No. WO 90/02809; Fuchs et al. (1991) Bio/Technology 9: 1370-1372; Hay et al (1992) Hum. Antibod. Hybridomas 3:81-85; Huse et al. (1989) Science 246:1275- 1281; Griffiths et al. (1993) EMBO J 12:725-734; Hawkins et al. (1992) J. Mol. Biol. 226:889-896; Clarkson et al. (1991) Natur 352:624-628; Gram et al. (1992) Proc. Natl. Acad. Sci. USA 89:3576-3580; Garrad et a/. (1991) Bio/Technology 9:1373-1377; Hoogenboom et al. (1991) Nwc. Acid Res. 19:4133-4137; Barbas et al. (1991) Proc. Natl. Acad. Sci. USA 88:7978-7982; and McCafferty et al. (1990) Nature 348:552-554. Additionally, recombinant anti-FOXO3a antibodies, such as chimeric and humanized monoclonal antibodies, comprising both human and non-human portions, which can be made using standard recombinant DΝA techniques, are within the scope of the methods of the invention. Such chimeric and humanized monoclonal antibodies can be produced by recombinant DNA techniques known in the art, for example using methods described in Robinson et al. International Application No. PCT/US86/02269; Akira, et al. European Patent Application 184,187; Taniguchi, M., European Patent Application 171,496; Morrison et al. European Patent Application 173,494; Neuberger et al. PCT International Publication No. WO 86/01533; Cabilly et al. U.S. Patent No. 4,816,567; Cabilly et al. European Patent Application 125,023; Better et al. (1988) Science 240:1041-1043; Liu et al. (1987) Proc Natl. Acad. Sci. USA 84:3439-3443; Liu et al. (1987) J. Immunol. 139:3521-3526; Sun et al. (1987) Proc. Natl. Acad. Sci. USA 84:214-218; Nishimura et at^". (1987) Cane Res. 47:999-1005; Wood et al. (1985) Nature 314:446-449; Shaw et al. (1988) J. Nad. Cancer Inst. 80:1553-1559; Morrison, S. L. (1985) Science 229: 1202- 1207; Oi et al. (1986) BioTechniques 4:214; Winter U.S. Patent 5,225,539; Jones et al. (1986) Nature 321:552-525; Verhoeyan et al. (1988) Science 239:1534; and Beidler et al. (1988) J. Immunol. 141 :4053-4060. An anti-FOXO3a antibody can be used to detect FOXO3a protein (e.g. , in a cellular lysate or cell supernatant) in order to evaluate the abundance and pattern of expression of the FOXO3a protein. Anti-FOXO3a antibodies can be used diagnostically to monitor protein levels in tissue as part of a clinical testing procedure, e.g., to, for example, determine the efficacy of a given treatment regimen. Detection can be facilitated by coupling (i.e., physically linking) the antibody to a detectable substance. Examples of detectable substances include various enzymes, prosthetic groups, fluorescent materials, luminescent materials, bioluminescent materials, and radioactive materials. Examples of suitable enzymes include horseradish peroxidase, alkaline phosphatase, β-galactosidase, or acetylcholinesterase; examples of suitable prosthetic group complexes include streptavidin/biotin and avidin/biotin; examples of suitable fluorescent materials include umbelliferone, fluorescein, fluorescein isothiocyanate, rhodamine, dichlorotriazinylamine fluorescein, dansyl chloride or phycoerythrin; an example of a luminescent material includes luminol; examples of bioluminescent materials include luciferase, luciferin, and aequorin, and examples of suitable radioactive material include ^{1 5}1, ¹³¹I, ³⁵S or ³H.

This invention is further illustrated by the following Exemplification which should not be construed as limiting. The contents of all references, sequences, Figures, and published patent applications cited throughout this application are hereby incoφorated by reference. EXAMPLES

Materials and Methods The following materials and methods were used for the experiments described below.

Targeting construct, genotyping, colony generation and analysis. The Foxo3a genomic region encompassing exons 1 and 2 was cloned and mapped the from a bacterial artificial chromosome library. The targeting vector (Figure 1 A) carried a negative selection marker for diphtheria toxin (DT), a positive selection marker for neomycin resistance (Neo), Frt sites (white rectangles) and loxP sites (white triangles). TCI embryonic stem cells were electroporated and transformed cells were selected by standard techniques. Clones (n=96) were screened by Southern analysis of Nhel digested DNA using a 3' probe external to the targeting construct (Figure IA, probe B) to identify 6 recombinants that contained the distal loxP site. Blastocyst injections were carried out and transmitting chimaeric mice were bred with Ella-Cre transgenic mice (Lakso, M., et al 1996. Proc Natl Acad Sci USA 93:5860) to generate the Foxo3a^~ allele. Foxo3a^'/+ animals were backcrossed three times to FVB/n females and progeny of these matings that were Cre^" were then intercrossed with littermates to generate the experimental cohort. Mice were genotyped by multiplex PCR.

Whole animal studies, dissection, histological analyses and vaginal smears. For continuous breeding assays, single mating pairs were placed per cage, which were inspected every morning. Litters were weaned at 3 weeks. Animals were fed ad libitum on standard chow and weighed at weaning (3 weeks) and subsequently every 2 or 3 weeks. For determinations of age of sexual maturity and first litter sizes, single pair matings were set up between 21 -day old experimental females and FVB stud males. For histological analyses, ovaries were freed from their capsule, immediately placed in 10%) buffered formalin, embedded in paraffin, serially sectioned (6μm) and stained with hematoxylin and eosin or PAS. Ovaries from 4 or more animals of each genotype were subjected to gross and microscopic analysis for each time point (Figure 3); controls in all cases were siblings. Primordial follicles were defined as having an oocyte sunounded by a single layer of squamous GCs. Early growing follicles in Foxo3a^'A females were readily identified by their large oocyte diameter (at least 2x the width of the germinal vesicle). Primary follicles were defined as having enlarged oocytes surrounded by a single layer of cuboidal GCs, and secondary follicles were defined as having at least a partial second layer of GCs. Because it was difficult to reliably ascertain viability in the early growing follicles in Foxo3a^' ovaries especially at 4.5 and 8.5 weeks, GC death was the sole criterion used to identify atretic follicles. Zona pellucida remnants were counted on sections stained with PAS. For histomoφhometric analyses of PD3 ovaries, every 5^th section was photographed for oocyte counts. For analyses of follicles at later stages, 5 approximately equidistant sections were counted. Vaginal smears were obtained every morning for 4 consecutive weeks by instillation of 20-30 μl of PBS. Samples were smeared on glass slides, allowed to dry, and stained with Giemsa. For determinations of oocyte diameter, hematoxylin and eosin stained sections were prepared as above, and the long diameter of oocytes with nuclei in section determined from photographs.

Superovulations, ovarian whole organ culture, expression studies, and hormone measurements. Female mice at 21 or 32 days of age were injected with 5 IU pregnant mare serum (Gestyl, Professional Compounding Center of America) followed by 5 IU hCG (Pregnyl, Organon) 48 hours later, and a stud male placed in with each female .at the time of hCG injection. Ovarian whole organ culture was carried out in Waymouth medium supplemented with 10% fetal bovine serum; ovaries were placed on Costar Transwell membranes (non-tissue culture treated, 3 μm pore size, 24 mm diameter) as described (Eppig, J. J. and O'Brien, M. J. 1996. Biology of Reproduction 54:197). Ovaries were photographed at explantation, and at 4 and 8 days, and the volume, V, estimated by the equation, V=(long diameter X short diameter²). Total mouse ovary RNA was prepared using an Rneasy Mini Kit (Qiagen), and amplified by real-time RT- PCR (Quantitect SYBR RT-PCR, Qiagen) using an ABI Prism 7700 Sequence Detector with intron-spanning Foxo3a specific primers. The sequences of the intron-spanning Foxo3a specific primers are as follows:

OFKHR2-30- ACAAACGGCTCACTTTGTCC (SEQ ID NO: 10); oFKHR2-31-CTGTGCAGGGACAGGTTGT (SEQ ID NO:l 1). RT-PCR products of the correct size were confirmed by agarose gel electrophoresis. Human fetal tissues were obtained following Institutional Review Board Approval and total RNA prepared using TRIZOL per the manufacturer's instructions (Invitrogen). An adult tissue Northern blot was obtained from a commercial source (Clontech). Serum FSH and LH measurements were performed using a competitive enzyme immunoassay system (Biotrak) per the manufacturer's instructions (Amersham). EXAMPLE 1 : THE TARGETING STRATEGY AND ANALYSIS OF THE DISRUPTED FOX03a GENE To uncover in vivo functions of Foxo3a, mice bearing a null mutation in the Foxo3a locus were generated. Molecular analysis confirmed homologous recombination at the Foxo3a locus of the targeting construct containing the neomycin resistance gene (Figures 1A,B). Deletion of the first coding exon, which encodes the start codon and the N-terminal half of the protein and forkhead DNA binding domain, was confirmed by additional molecular analyses (Figure 1C). Intercrosses between Foxo3a^'/+ mice yielded Foxo3d'^~ offspring at Mendelian frequencies: of 444 such progeny 111 (25.0%) were Foxo3a^+/+, 212 (47.7%) Foxo3d^/+, and 121 (27.3%) Foxo3d ^A. Deletion of the first coding exon in nullizygous animals was further confirmed by Northern analysis of RNA derived from adult tissues (Figure ID). Similar to previous reports (Biggs, 3rd, W. H., et al. 2001. Mamm Genome 12:416; Furuyama, T., et al. 2000. Biochem J 349:629; Richards, J. S., et al. 2002. Mol Endocrinol 16:580) it was found that Foxo3a expression was readily detectable in a wide range of mouse tissues including the ovary, reproductive organs (Figure IE) and other tissues including liver (Figure ID) and brain, lung, spleen, skeletal muscle, and prostate. To explore potential roles of Foxo3a in cell growth and survival, mouse embryo fibroblast lines (MEFs) were generated, in which Foxo3a is highly expressed (Figure IE). No differences in the growth or survival properties of Foxo3a^{+ +} and Foxo3d MEFS were seen in serum concentrations ranging from 1 to 10%, upon addition of low doses of agents that induce oxidative stress or DNA damage, including hydrogen peroxide, paraquat, and adriamycin, or under hypoxic conditions (1% O₂). Cell cycle analyses and serial transfer (3T3) assays also failed to uncover significant differences between Foxo3a^{+ +} and Foxo3a^'A MEFS. These findings are consistent with the view that Foxo3a serves physiologic roles in the homeostasis of various organ systems in living animals.

EXAMPLE 2: PHENOTYPIC CHARACTERIZATION OF FOXO3 ^ΛMICE Despite this broad pattern of expression, Foxo3a^{~ '} animals appeared outwardly normal, showing no prevalent patterns of disease-associated morbidity including increased spontaneous tumor formation, abnormal weight gain (Figure 2A) or statistically significant differences in mortality up to 48 weeks of age. However, it remains possible that age-related or cancer phenotypes will become apparent in older mice. Evaluation of peripheral blood smears showed that Foxo3a^{' '} animals exhibit hematologic abnormalities including a mild, compensated anemia (with associated reticulocytosis). Foxo3a^'A also exhibited decreased glucose uptake following overnight fast. Extensive histologic surveys of over 20 Foxo3a^'A mice ranging in age from 4 to 30 weeks revealed no significant recurring pathologic abnormalities, except in the ovaries. All stages of spermatogenesis appeared normal, epididymides contained large numbers of motile sperm, and males showed no evidence of subfertility through 30 weeks of age (N=8). In contrast to males, females exhibited a marked age-dependent decline in reproductive fitness. Foxo3a ^~ females were initially capable of bearing normal litters that were successfully weaned but had fewer and smaller litters with advancing age, and were sterile by 15 weeks of age (Figure 2B). Foxo3a^'A and control (- /+) and (+/+) females (N ≥4 per genotype) bore first litters at 57.0±1.7, 57.5±2.6, and 58±3.5 days of age, respectively, and these litters consisted of similar numbers of viable newborn pups (8.25±0.3, 7±0.4, and 7.75±0.7). These results are consistent with normal sexual maturation in Foxo3d^A females. The smaller litter sizes observed in aging Foxo3d females (Figure 2B) are consistent with this oocyte deterioration and death evident by 8.5 weeks of age.

EXAMPLE 3: GROSS AND HISTOLOGIC ANALYSIS OF FOX03 'AND CONTROL OVARIES Female infertility can result from a number of root causes, including disturbances of the pituitary/ovarian axis, a variety of systemic metabolic disorders, or intrinsic ovarian defects (Honore, L. H. 1997. Curr Opin Obstet Gynecol 9:37). Gross and histologic evaluation of Foxo3d^A females revealed no abnormalities of Mϋllerian structures or the pituitary. Ovaries from Foxo3d ⁺ and Foxo3d ^' females showed no size differences at birth or at postnatal day (PD) 3. However, by PD14, ovaries from Foxo3d ^" mice were consistently enlarged compared to controls (enlargement was evident as early as PD8), and this size difference persisted up to at least 8.5 weeks of age (Figure 3A). To understand the nature of the secondary infertility and ovarian enlargement evident in Foxo3d^A females, moφhologic analyses of ovaries at various ages were performed. Foxo3a^'/+ and Foxo3a^' ovaries were indistinguishable at PD3, containing large numbers of oocytes — most associated with a thin layer of flattened pregranulosa cells (Figure 3B). By PD14, however, Foxo3d^A ovaries contained dramatically elevated numbers of early growing follicles characterized by an increased oocyte diameter and flattened GCs (Figure 3B, insets). The oocytes in these early growing follicles in Foxo3d ^' PD 14 ovaries were of much larger diameter than those of comparable primordial follicles in controls (Figure 3B). Early growing follicles with enlarged oocytes but flattened GCs were a distinct feature of the Foxo3d^A mutant phenotype, and essentially absent in control ovaries at all ages (Fig. 3B, insets). At 8.5 weeks of age, Foxo3d^A ovaries exhibited large numbers of zona pellucida remnants (ZPR), remnants of oocytes which have undergone atresia subsequent to synthesis of the zona pellucida, which persists for some time following oocyte death (J. Dong, J., et al. 1996. Nature 383:531; Elvin, J. A., et al. 1999. Mol Endocrinol 13:1018) (Figure 3B). Of note, all of the oocytes in the remaining primordial follicles in Foxo3a^' ovaries by 8.5 weeks appeared large and misshapen (Figure 3B, inset), and many had fragmented nuclei; thus, the deregulation of follicular initiation that occurs in Foxo3d'^~ mice eventually leads to follicular/oocyte atresia in all follicles that do not progress. At 18 weeks Foxo3d ^' ovaries contained many ZPR and occasional old coφora lutea, but were entirely devoid of viable follicles at any stage of maturation, this in contrast to controls which contained follicles of all stages (Figure 3B).

EXAMPLE 4: HISTOMORPHOMETRIC ANALYSES OF FOXO3 ^A AND CONTROL OVARIES Histomoφhometric analysis showed similar numbers of oocytes in PD3 Foxo3a^{' +} and Foxo3d^A ovaries (Figure. 4A) and TUNEL assays demonstrated similar numbers of oocytes undergoing spontaneous apoptosis. The pervasive initiation of ovarian folliculogenesis in Foxo3d ^' females (characterized by an initial wave of oocyte growth) results in progression of increased numbers of follicles to more advanced stages of follicular development. Compared to age-matched Foxo3d ⁺ controls, counts of primary and secondary follicles showed a 1.9 and 2.1 -fold relative increase, respectively, in Foxo3d ^' ovaries at PD14 (Figure 4C, p=0.012 and 0.000). There was also as early as PD14 a large relative increase in the number of atretic secondary follicles, which were rare in the age-matched Foxo3a^'/+ controls at PD14 (Figure 4C, p=0.016). At 4.5 weeks of age, circa the onset of sexual maturity, many early growing follicles were still present in Foxo3d ^' ovaries (Figure. 4C), and the relative increases in the number of primary and secondary follicles (3.5 and 3.9x) (Figure 4D) were even more marked than at PD14. On the basis of the above findings, it is likely that this 14-fold increase in the number of ZPR reflects a record of increased follicular initiation followed by secondary follicular atresia in the null females (Figure 4E). In aged Foxo3d^/+ and Foxo3a^+/+ females (48 weeks), counts of primordial/primary follicles were similar, in contrast to Foxo3a^'A females, which were entirely depleted (Figure 4B). Since the number of remaining follicles is dependent upon the prior number of follicles initiating growth over the life of the animal, this finding suggests that mutation of only one Foxo3a allele has minimal impact on the rate of follicular initiation in the mouse (i.e., no evidence of Foxo3a haplosinsufficiency). However, because of longer lifespan in humans, it is likely that haploinsufficiency of FOX03a would impact the dynamics of follicle activation, resulting in a slight increase in the frequency of follicle activation that, over the reproductive lifespan of a woman, could result in premature ovarian failure (POF). Measurements of primordial oocyte size (in follicles with flattened GCs) revealed generalized oocyte enlargement as early as PD8 (Figure 4F). Study of size distributions confirmed that oocyte enlargement occurred in the great majority of oocytes by PD8, consistent with global or widespread activation or initiation (Figure 6). These activated oocytes in Foxo3d^A females grew until 4.5 weeks of age, reaching an average diameter of 48 microns, compared to 15.6 microns in normal primordial follicles in control ovaries (Figure 4F), despite the absence of GC growth and maturation. To investigate if Foxo3a is required within the ovary to suppress follicular initiation, ovaries from newborn females were explanted and cultured intact in vitro (Eppig, J. J. and O'Brien, M. J. 1996. Biology of Reproduction 54:197). Significant ovarian enlargement relative to controls was evident in Foxo3d ^' ovaries after eight days of culture (Figure 4G). Furthermore, this ovarian enlargement was associated with increased oocyte diameters (Figure 4H), similar in magnitude to that observed in vivo in Foxo3d ovaries (Figure 4F). The recapitulation of these ovarian phenotypes following in vitro organ culture suggest that Foxo3a functions within the ovary itself to suppress follicular initiation, and that circulating factors produced outside the ovary are not likely to have an essential role in the suppression of follicular initiation mediated by Foxo3a.

EXAMPLE 5: HORMONAL ANALYSES OF FOXO3 ⁷ AND CONTROL ANIMALS Follicular depletion whether in the setting of menopause or premature ovarian failure results in elevation of serum gonadotropin levels, due to loss of feedback inhibition upon the pituitary (Anasti, J. N. 1998. Fertil Steril 70: 1). To confirm this signature physiologic response in Foxo3d ^' females, serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels were measured at 20 weeks of age. Compared to Foxo3a^+/+ controls, Foxo3d^A females showed significant elevations in both FSH and LH levels (Figure 5 A, p=0.000 and 0.001 ). Therefore, Foxo3a ^~ females exhibit classic signs of hypergonadotropic hypogonadism due to premature ovarian failure, indicating normal pituitary function in response to follicular depletion. To further assess ovulation in Foxo3d^A females, serial (daily) vaginal smears were obtained for cytologic evaluation. Whereas all heterozygous and wild-type control females cycled regularly during 4-week observation periods, Foxo3d ^' females cycled sporadically from 6 to 15 weeks, but were subsequently completely acyclic, consistent with a rapid decline and subsequent total depletion of follicular reserve and consequent ovarian failure. To investigate further the dynamics of follicular growth and selection in Foxo3d ovaries, ovulation was induced by administration of gonadotropins ("superovulation") at 3.0 and 4.5 weeks of age. At 3 weeks, the number of released eggs following superovulation were similar among +/+, -/+ and -/- females (Figure 5B), and >90% of these released eggs were competent to develop to the blastula stage in culture. These results demonstrate that Foxo3a is not required for gonadotropin responsiveness, as expected given the ability of Foxo3d^A females to bear litters prior to follicular depletion around 15 weeks of age. At 4.5 weeks of age, more eggs were released by Foxo3d females relative to controls (Figure 5B, p=0.039), likely a reflection of the greater numbers of advanced follicles observed in older Foxo3d^A animals. Taken together, the above findings suggest that lack of Foxo3a function results in an intrinsic ovarian defect specifically involving follicular growth initiation, without impairing other aspects of follicular maturation or reproduction.

EXAMPLE 6: EXPRESSION ANALYSES OF FOXO3a IN HUMAN TISSUES Expression of Foxo3a is readily detectable by in situ hybridization throughout the adult mouse ovary (Richards, J. S., et al. 2002. Mol Endocrinol 16:580). To determine if Foxo3a is expressed in ovaries of young animals prior to the earliest observed Foxo3d phenotype, real time RT-PCR was performed on PD3 ovaries. Foxo3a specific products were detected in PD3 ovaries from Foxo3a^{+ +} but not Foxo3 ^' ovaries, which served as a negative control confirming that Foxo3a transcripts are present in the mouse ovary at a time-point preceding the earliest manifestation of the Foxo3d ^' phenotype. It was also discovered that FOX03a expression was readily detectable in human newborn and adult ovaries (Figure 7) as has been previously shown for adult human ovaries (Biggs, 3rd, W. H., et al. 2001. Mamm Genome 12:416). Since FOXO3a is expressed in the juvenile as well as the adult human ovary, FOXO3a serves a conserved role in the regulation of follicular initiation in women.

EXAMPLE 7: IDENTIFICATION OF POLYMORPHISMS IN THE FOX03a GENE Starting with 0.1 ug of human DNA (i.e., from blood samples) the two exons of foxo3a (SEQ ID NO:l) were amplified in two separate reactions with each primer pair shown below. The amplified fragments are purified and sequenced with the M13R and F primers to obtain the entire sequence of each exon. The amplified sequences are then compared to the normal cDNA sequence (SEQ ID NO:l) to identify sequence variants. Below are the primers used for amplification of both human FOXO3a coding exons (primers have sequences for M13F or M13R Universal primers at 5' ends):

EXON1 amplification and sequencing (product size ~0.8 kb).

Conditions 95Cx2min; 95Cx30s— 55Cx30s— 72Cx 2min (35 cycle). oFoxo3aElf-GTAAAACGACGGCCAGTGAGAGGAGAGCGCGAGAG (SEQ ID NO:3) and

oFoxo3aElr-AACAGCTATGACCATGACTCCGACGAATCCGAGAC (SEQ ID NO:4).

EXON2 amplification and sequencing (product size ~1.6 kb). Conditions 95Cx2min; 95Cx30s— 52Cx30s— 72Cx 2min (35 cycle):

oFoxo3aE2f-GTAAAACGACGGCCAGTTATATCATCTGGGTGCTCGGTTTT (SEQ ID NO:5) and

ofoxo3aE2r-AACAGCTATGACCATGCCCCTCATCCCCATATTGTTATT (SEQ ID NO:6).

There are four preferred polymoφhisms identified in the FOXO3a gene. One polymoφhism is a change from a cytidine (C) to a thymidine (T) in the THBS1 gene at residue 1,083 of the FOXO3a gene (set forth as SEQ ID NO:l). This polymoφhism does not result in a change in the amino acid sequence of the THBS1 protein (it is a "silent" variant). A second polymoφhism is a change from a cytidine (C) to a thymidine (T) at residue 1,343 of the FOXO3a gene (set forth as SEQ ID NO:l). This polymoφhism is results in a change from an Alanine to a Valine in the amino acid sequence of the FOXO3a protein (set forth as SEQ ID NO:2), at amino acid residue 140. A third polymoφhism is a change from a guanidine (G) to an adenine (A) at residue 1,945 of the FOXO3a gene (set forth as SEQ ID NO:l). This polymoφhism is results in a change from an Alanine to a Threonine in the amino acid sequence of the FOXO3a protein (set forth as SEQ ID NO:2), at amino acid residue 341. A fourth polymoφhism is a change from a cytidine (C) to a thymidine (T) at residue 2,781 of the FOXO3a gene (set forth as SEQ ED NO:l). This polymoφhism is a silent variation.

Equivalents Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

What is claimed:

1. A method for modulating ovarian follicular initiation in a female subject comprising contacting FOXO3a or a cell expressing FOXO3a with a FOXO3a modulator, thereby modulating ovarian follicular initiation in a female subject.

2. The method of claim 1, wherein said subject is human.

3. The method of claim 1, wherein said modulator is a small molecule.

4. The method of claim 1, wherein said compound is a FOXO3a antibody.

The method of claim 1, wherein said compound is a peptide.

6. The method of claim 1, wherein said compound is a peptidomimetic.

7. The method of claim 1, wherein said FOXO3a modulator modulates c-Kit expression or activity.

8. The method of claim 7, wherein said FOXO3a modulator inhibits c-kit expression or activity.

The method of claim 8, wherein said c-Kit inhibitor is imatinib mesylate (Gleevec™).

10. The method of claim 1, wherein said FOXO3a modulator modulates protein kinase AKT expression or activity.

11. The method of claim 1, wherein the FOXO3a modulator increases FOXO3a expression or activity, thereby suppressing follicular initiation.

12. The method of claim 11, wherein said method is used in contraception.

13. The method of claim 1 , wherein the FOXO3a modulator decreases FOXO3a expression or activity, thereby increasing follicular initiation.

14. The method of claim 13, wherein follicular initiation is increased such that functional ovarian follicles are depleted.

15. The method of claim 13, wherein follicular initiation is increased such that infertility occurs.

16. A method for modulating fertility in a female subject comprising contacting FOXO3a or a cell expressing FOXO3a with a FOXO3 modulator, thereby modulating fertility in a female subject.

17. The method of claim 16, wherein said subject is human.

18. The method of claim 16, wherein the expression or activity of FOXO3a is increased.

19. The method of claim 18, wherein said method is used in contraception.

20. The method of claim 16, wherein the expression or activity of FOXO3a is decreased.

21. The method of claim 20, wherein said method causes infertility in said subject.

22. The method of claim 16, wherein said modulator is a small molecule.

23. The method of claim 16, wherein said compound is a peptide.

24. The method of claim 16, wherein said compound is a peptidomimetic.

25. The method of claim 16, wherein said FOXO3a modulator modulates c-Kit expression or activity.

26. The method of claim 25, wherein said FOXO3a modulator inhibits c-kit expression or activity.

27. The method of claim 26, wherein said c-Kit inhibitor is imatinib mesylate (Gleevec ).

28. The method of claim 16, wherein said FOXO3a modulator modulates protein kinase AKT expression or activity.

29. A method for treating infertility in a female subject comprising administering to said female subject a FOXO3a antagonist such that follicular initiation is increased, wherein said FOXO3a antagonist is administered in an amount effective to increase follicular initiation without depleting functional ovarian follicles, thereby treating infertility in a female subject.

30. The method of claim 29, wherein said subject is human.

31. The method of claim 29, wherein said FOXO3a antagonist is administered to said subject in combination with a gonadotropin.

32. The method of claim 31, wherein said FOXO3a and said gonadotropin are administered serially.

33. The method of claim 31, wherein said FOXO3a and said gonadotropin are administered concunently.

34. The method of claim 31, wherein said gonadotropin is follicle stimulating hormone (FSH) or leuteinizing hormone (LH), or a combination of both.

35. A method for treating a hormone-related disease or disorder in a subject comprising administering to said subject an effective amount of a FOXO3a antagonist, thereby treating a hormone-related disease or disorder in a subject.

36. The method of claim 35, wherein said subject is human.

37. The method of claim 35, wherein said subject is female.

38. The method of claim 35, wherein said hormone-related disease or disorder is selected from the group consisting of: hormone-dependent tumor or migraine.

39. The method of claim 35, wherein said FOXO3a antagonist is administered in an amount effective to increase follicular initiation without depleting functional ovarian follicles.

40. A non-human animal, in which the gene encoding the FOXO3a gene is misexpressed.

41. The animal of claim 40, wherein said animal is a transgenic animal.

42. The animal of claim 41, wherein said transgenic animal is a mouse.

43. The animal of claim 40, wherein the FOXO3a gene is disrupted by removal of DNA encoding all or part of the FOXO3a protein.

44. The animal of claim 43, wherein said animal is homozygous for the disrupted gene.

45. The animal of claim 43, wherein said animal is heterozygous for the disrupted gene.

46. The animal of claim 40, wherein said animal is a transgenic mouse with a transgenic disruption of the FOXO3a gene.

47. The animal of claim 46, wherein said disruption is an insertion or deletion.

48. A method for identifying a candidate compound useful as a contraceptive, comprising: a) contacting FOXO3a with a test compound; b) determining the activity or expression of FOXO3a in the presence of said test compound; c) selecting a compound that increases the activity or expression of FOXO3a; and d) identifying said selected compound as a candidate compound useful as a contraceptive.

49. A method for identifying a candidate compound useful as a contraceptive, comprising: a) contacting a cell expressing FOXO3a with a test compound; b) determining the expression of the FOXO3a gene or the activity of FOXO3a in the presence of said test compound; c) selecting a compound that increases the expression of the FOXO3a gene or the activity of FOXO3a; and d) identifying said selected compound as a candidate compound useful as a contraceptive.

50. The method of claims 48 or 49, wherein said compound is a small molecule.

51. The method of claim 48 or 49, wherein said compound is a peptide.

52. The method of claim 48 or 49, wherein said compound is a peptidomimetic.

53. A method for identifying a candidate compound useful as a contraceptive comprising: a) contacting FOXO3a with a test compound; and b) assaying for modulation of the expression or activity of FOXO3a in the presence of said test compound, wherein an increase of the expression or activity of FOXO3a by the test compound identifies the test compound as a candidate compound useful as a contraceptive.

54. A method for identifying a candidate compound useful as a contraceptive comprising: a) contacting a cell expressing FOXO3a with a test compound; b) assaying for modulation of the expression or activity of FOXO3a in the presence of said test compound, wherein an increase of the expression or activity of FOXO3a by the test compound identifies the test compound as a candidate compound useful as a contraceptive.

55. A method for identifying a compound capable of modulating the expression or activity of FOXO3a comprising: a) contacting a cell expressing FOXO3a with a test compound; b) determining the effect of the test compound on the expression or activity of FOXO3a in the presence of said test compound to thereby identify a compound which modulates the expression or activity of FOXO3a.

56. A method for identifying a compound capable of modulating the expression or activity of FOXO3a comprising: a) contacting FOXO3a with a test compound; and b) determining the effect of the test compound on the expression or activity of FOXO3a in the presence of said test compound to thereby identify a compound which modulates the expression or activity of FOXO3a.

57. A method for predicting premature ovarian failure or a risk for premature ovarian failure in a subject comprising detecting the expression of the FOXO3a gene or the activity of FOXO3a in a cell or tissue of a subject, wherein a decrease in the expression of the FOXO3a gene or the activity of FOXO3a indicates premature ovarian failure or a risk for premature ovarian failure in a subject.

58. The method of claim 57, wherein said tissue is ovarian tissue.

59. A method of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: (a) obtaining a nucleic acid sample from the subject; and (b) determining the identity of the nucleotide at nucleotide position 1,083 of SEQ ID NO: l, or the complement thereof, wherein the presence of at least one thymidine (T) allele at nucleotide position 1,083 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject.

60. A method of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: (a) obtaining a nucleic acid sample from the subject; and (b) determining the identity of the nucleotide at nucleotide position 1,343 of SEQ ID NO:l, or the complement thereof, wherein the presence of at least one thymidine (T) allele at nucleotide position 1,343 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject.

61. A method of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: (a) obtaining a nucleic acid sample from the subject; and (b) determining the identity of the nucleotide at nucleotide position 1,945 of SEQ ID NO:l, or the complement thereof, wherein the presence of at least one adenine (A) allele at nucleotide position 1,945 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject.

62. A method of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: (a) obtaining a nucleic acid sample from the subject; and (b) determining the identity of the nucleotide at nucleotide position 2,781 of SEQ ID NO:l, or the complement thereof, wherein the presence of at least one thymidine (T) allele at nucleotide position 2,781 of SEQ ID NO:l, or the complement thereof, is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject.

63. The method of any one of claims 59, 60, 61, or 62, wherein determining comprises contacting a nucleic acid of the subject with at least one probe or primer which is capable of hybridizing to a FOXO3a gene.

64. A method of claim 63, wherein the probe or primer is capable of specifically hybridizing to an allelic variant.

65. A method of any one of claims 59, 60, 61 , or 62, wherein the probe or primer has a nucleotide sequence from about 15 to about 30 nucleotides.

66. A method of any one of claims 59, 60, 61, or 62, wherein the probe or primer is a single stranded nucleic acid.

67. The method of claim 59 or 60, wherein determining is earned out by amplifying a portion of SEQ ID NO:l using the primers set forth as SEQ ID NO:3 and SEQ ID NO:4.

68. The method of claim 61 or 62, wherein determining is carried out by amplifying a portion of SEQ ID NO:l using the primers set forth as SEQ ID NO:5 and SEQ ID NO:6.

69. A method of claim 63, wherein the probe or primer is labeled.

70. A method of any one of claims 59, 60, 61, or 62, wherein determining is carried out by allele specific hybridization.

71. A method of any one of claims 59, 60, 61, or 62, wherein determining is carried out by primer specific extension.

72. A method of any one of claims 59, 60, 61, or 62, wherein determining is carried out by an oligonucleotide ligation assay.

73. A method of any one of claims 59, 60, 61, or 62, wherein determining is carried out by single-stranded conformation polymoφhism.

74. A method of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: (a) obtaining a FOXO3a protein sample from the subject; and (b) determining the identity of the amino acid at amino acid position 140 of SEQ ID NO:2, wherein the presence of Valine (Val) at amino acid position 140 is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject as compared with a subject having Alanine (Ala) at this position.

75. A method of diagnosing or aiding in the diagnosis of premature ovarian failure or a risk for premature ovarian failure in a subject comprising the steps of: (a) obtaining a FOXO3a protein sample from the subject; and (b) determining the identity of the amino acid at amino acid position 341 of SEQ ID NO:2, wherein the presence of Threonine (Thr) at amino acid position 341 is indicative of premature ovarian failure or a risk for premature ovarian failure in the subject as compared with a subject having Alanine (Ala) at this position.