WO2000078950A2 - Differentially expressed genes in the adipocytes of obese mice - Google Patents

Abstract

The present invention relates to novel OMA polypeptides, nucleotide sequences encoding the novel OMA polypeptides, as well as various products and methods useful for the diagnosis and treatment of various OMA-related diseases and conditions.

Description

DESCRIPTION

Differentially Expressed Genes in the Adipocvtes of Obese Mice

Field Of The Invention

The present invention relates to novel polypeptides, nucleotide sequences encoding the novel polypeptides, as well as various products and methods useful for the diagnosis and treatment of various related diseases and conditions.

Background Of The Invention

The following description of the background of the invention is provided to aid in understanding the invention, but is not admitted to be, or to describe, prior art to the invention.

Obesity is a highly prevalent condition in affluent societies correlated with increased mortality. Present therapies have only moderate success. The prediction of a factor that limited fat storage was recently confirmed by the identification of leptin (ob protein), produced almost exclusively in fat, and that commonly increases with obesity. Tumor necrosis factor alpha (TNFα) is another peptide that shares several of the functional features of leptin: present in fat; elevated in obesity; and inhibits appetite. Redundancy, or multiple parallel or nested control loops, is a common feature of biological control systems. In this way, several mechanisms functioning via separate biochemical pathways operate to control a single important variable. It is possible that undiscovered additional signaling pathways for control of body energy content exist. Fat stores, typically representing >76% of body energy content, are a possible tissue in which to search for such pathways. Modulators of these signaling pathways could represent novel drugs for the treatment of obesity and related metabolic disorders.

Obesity, defined as an excess of body fat relative to lean body mass, represents a major health problem in all developed countries. Obese individuals are at increased risk of a number of serious diseases and disorders such as coronary artery disease, stroke, high blood pressure, insulin resistance and diabetes. The exact cause of obesity is not clearly understood but is likely the result of a loss of control in one or multiple biochemical mechanisms, either metabolic or neurologic, involved in mediating the quantity of fat mass. As adipose tissue is the major long-term store of energy for the body, maintenance of fat mass is entwined with the physiological signals to obtain and metabolize food. Several animal models exist which have mutations which result in obesity. Two of the best studied animal models for genetic obesity are mice containing the autosomal recessive mutations ob/ob (obese) and db/db (diabetes). The ob/ob mice contain a mutation in the gene coding for the protein leptin. The mutation results in the production of a truncated leptin protein which is not biologically active. When ob/ob mice are given intact, biologically active leptin, they immediately start to lose weight. The db/db mice contain a mutation in the gene encoding the leptin receptor expressed in the hypothalamus. Whereas the db/db mice have biologically active leptin, the mutation in the receptor does not allow for proper signaling which results in the obese phenotype. The ob/ob and db/db mice represent genetic models of obesity. It is possible to induce obesity in normal animals by chemical methods, and one such method utilizes gold aurothioglucose (GTG). A single injection of GTG causes a bilateral necrosis of a circumscribed region of the ventromedial hypothalamus (VMH) (Liebelt and Perry, Handbook of Physiology, Volume 1, pp 271-285,1967; Marshall, NB, et al, Proc Soc Exp Bio Med, 90, pp 240-244, 1955). The selective affinity of hypothalamic cells for the glucose moiety of gold thioglucose is thought to be responsible for the accumulation ofthe compound and the subsequent destruction of the cells causing the animal to be hyperphagic and obese.

Despite the prevalence of animal models of obesity, studies to date have not identified a gene in humans which is primary to the etiology of this disorder. Understanding the genetic basis of obesity is critical considering the health risks associated with this disorder and the increase in the obese population in developed countries.

Summary Of The Invention Adipose tissue has long been regarded simply as a store of energy for metabolism.

However, with the discovery of leptin, adipose tissue is now considered as having an active role in regulating certain regulatory pathways involved in maintaining fat mass. Besides leptin, TNF-α is secreted from adipose cells and has been demonstrated to inhibit appetite. There is a genetic basis underlying many, if not all, disease states and disorders, including obesity. Therefore, it is possible to uncover novel genes involved in regulating adiposity by analyzing gene expression in the adipose tissue of lean animals versus obese animals. The technique of differential display, also referred to as RNA finge rinting, allows for a comparison of genes that may be up- or down-regulated in the obese state when compared to lean controls. Isolation and characterization of differentially regulated genes in obese animal models may lead to novel therapies for controlling fat mass or novel diagnostic tools in evaluating obesity. Discovery of genes having a novel role in the biology of the adipocyte may lead to new treatments for the obese individual. Differential display is one technique which allows for the identification of novel genes upregulated in the obese state.

Disclosed herein are a group of polypeptides, preferentially expressed in the adipocytes of obese mice, which we have named "obese mice adipocyte polypeptides" or "OMA polypeptides". By "OMA polypeptide" it is meant a polypeptide selected from the group consisting of P4P6B1, P7P7C1, P10P10C5, and P6P7A. These proteins are described in detail below. The properties of OMA polypeptides are described below. The present invention concerns OMA polypeptides, nucleic acids encoding such polypeptides, cells, tissues and animals containing such nucleic acids, antibodies to the polypeptides, assays utilizing the polypeptides, and methods relating to all ofthe foregoing.

A first aspect of the invention features an isolated, enriched, or purified nucleic acid molecule encoding an OMA polypeptide or encoding a fragment of an OMA polypeptide. By "isolated" in reference to nucleic acid it is meant a polymer of 14, 17, 21 or more nucleotides conjugated to each other, including DNA or RNA that is isolated from a natural source or that is synthesized. The isolated nucleic acid of the present invention is unique in the sense that it is not found in a pure or separated state in nature. Use of the term "isolated" indicates that a naturally occurring sequence has been removed from its normal cellular (i.e., chromosomal) environment. Thus, the sequence may be in a cell-free solution or placed in a different cellular environment. The term does not imply that the sequence is the only nucleotide sequence present, but that it is essentially free (about 90-95% pure at least) of nucleotide material naturally associated with it and thus is meant to be distinguished from isolated chromosomes. By the use of the term "enriched" in reference to nucleic acid it is meant that the specific DNA or RNA sequence constitutes a significantly higher fraction (2-5 fold) of the total DNA or RNA present in the cells or solution of interest than in normal or diseased cells or in the cells from which the sequence was taken. This could be caused by a person by preferential reduction in the amount of other DNA or RNA present, or by a preferential increase in the amount of the specific DNA or RNA sequence, or by a combination of the two. However, it should be noted that "enriched" does not imply that there are no other DNA or RNA sequences present, just that the relative amount of the sequence of interest has been significantly increased.

The term "significant" here is used to indicate that the level of increase is useful to the person making such an increase, and generally means an increase relative to other nucleic acids of about at least 2 fold, more preferably at least 5 to 10 fold or even more. The term also does not imply that there is no DNA or RNA from other sources. The other source DNA may, for example, comprise DNA from a yeast or bacterial genome, or a cloning vector such as pUC19. This term distinguishes the sequence from naturally occurring enrichment events, such as viral infection, or tumor type growths, in which the level of one mRNA may be naturally increased relative to other species of mRNA. That is, the term is meant to cover only those situations in which a person has intervened to elevate the proportion ofthe desired nucleic acid.

It is also advantageous for some purposes that a nucleotide sequence be in purified form. The term "purified" in reference to nucleic acid does not require absolute purity (such as a homogeneous preparation); instead, it represents an indication that the sequence is relatively purer than in the natural environment (compared to the natural level this level should be at least 2-5 fold greater, e.g., in terms of mg/mL). Individual clones isolated from a cDNA library may be purified to electrophoretic homogeneity. The claimed DNA molecules obtained from these clones can be obtained directly from total DNA or from total RNA. The cDNA clones are not naturally occurring, but rather are preferably obtained via manipulation of a partially purified naturally occurring substance (messenger RNA). The construction of a cDNA library from mRNA involves the creation of a synthetic substance (cDNA) and pure individual cDNA clones can be isolated from the synthetic library by clonal selection of the cells carrying the cDNA library. Thus, the process which includes the construction of a cDNA library from mRNA and isolation of distinct cDNA clones yields an approximately 10⁶-fold purification of the native message. Thus, purification of at least one order of magnitude, preferably two or three orders, and more preferably four or five orders of magnitude is expressly contemplated. The term is also chosen to distinguish clones already in existence which may encode an OMA polypeptide but which have not been isolated from other clones in a library of clones. Thus, the term covers clones encoding an OMA polypeptide which are isolated from other non-OMA clones.

The term "nucleic acid molecule" describes a polymer of deoxyribonucleotides (DNA) or ribonucleotides (RNA). The nucleic acid molecule may be isolated from a natural source by cDNA cloning or subtractive hybridization or synthesized manually. The nucleic acid molecule may be synthesized manually by the triester synthetic method or by using an automated DNA synthesizer.

The term "cDNA cloning" refers to hybridizing a small nucleic acid molecule, a probe, to cDNA. The probe hybridizes (binds) to complementary sequences of cDNA.

The term "complementary" describes two nucleotides that can form multiple favorable interactions with one another. For example, adenine is complementary to thymine as they can form two hydrogen bonds. Similarly, guanine and cytosine are complementary since they can form three hydrogen bonds. Thus if a nucleic acid sequence contains the following sequence of bases, thymine, adenine, guanine and cytosine, a "complement" of this nucleic acid molecule would be a molecule containing adenine in the place of thymine, thymine in the place of adenine, cytosine in the place of guanine, and guanine in the place of cytosine. Because the complement can contain a nucleic acid sequence that forms optimal interactions with the parent nucleic acid molecule, such a complement can bind with high affinity to its parent molecule.

The term "hybridize" refers to a method of interacting a nucleic acid sequence with a DNA or RNA molecule in solution or on a solid support, such as cellulose or nitrocellulose. If a nucleic acid sequence binds to the DNA or RNA molecule with high affinity, it is said to "hybridize" to the DNA or RNA molecule. The strength of the interaction between the probing sequence and its target can be assessed by varying the stringency of the hybridization conditions. Under highly stringent hybrydization conditions only highly complementary nucleic acid sequences hybridize. Preferably, such conditions prevent hybridization of nucleic acids having one or two mismatches out of 20 contiguous nucleotides.

Various low or high stringency hybridization conditions may be used depending upon the specificity and selectivity desired. Stringency is controlled by varying salt or denaturant concentrations. High stringent conditions may mean conditions that are at least as stringent as the following: hybridization in 50% formamide, 5x SSC, 50 mM NaH₃PO₄, pH 6.8, 0.5%) SDS, 0.1 mg/mL sonicated salmon sperm DNA, and 5x Denhart solution at 42 °C overnight; washing with 2x SSC, 0.1% SDS at 45 °C; and washing with 0.2x SSC, 0.1% SDS at 45 °C. Those skilled in the art will recognize how such conditions can be varied to vary specificity and selectivity.

An OMA polypeptide can be encoded by a full-length nucleic acid sequence or any portion of the full-length nucleic acid sequence. In preferred embodiments the isolated nucleic acid comprises, consists essentially of, or consists of a nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4, a nucleic acid sequence that hybridizes to the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4 or a functional derivative (as defined below) of either. The nucleic acid may be isolated from a natural source by cDNA cloning or subtractive hybridization; the natural source may be mammalian (human) blood, semen, or tissue and the nucleic acid may be synthesized by the triester or other method or by using an automated DNA synthesizer.

The term "mammalian" refers to such organisms as mice, rats, rabbits, goats, more preferably monkeys and apes, and most preferably humans.

In other preferred embodiments, the nucleic acid molecule of the invention comprises a nucleotide sequence that (a) has the nucleic acid sequence set forth in SEQ ID WO 00/78950 PCT/USOO/l 6217

NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or encodes a polypeptide having the full length amino acid sequence set forth in SEQ ID NO:5, or SEQ ID NO:6; (b) is the complement of the nucleotide sequence of (a);(c) hybridizes under highly stringent conditions to the nucleotide molecule of (a) and encodes a naturally occurring OMA polypeptide; (d) encodes an OMA polypeptide having the full length amino acid sequence of the sequence set forth in SEQ ID NO:5, or SEQ ID NO:6, except that it lacks one or more of the following segments of amino acid residues: 7-27, 49-68, 84-103, 139-157, 163-182, 184-207, 237-259, 272-294, 326-348, 377-399, 403-430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119-137, 138-160, 161-325, 326-354, 355-370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6; (e) is the complement of the nucleotide sequence of (d); (i) encodes a polypeptide having the amino acid sequence set forth in SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, or SEQ ID NO:8 from amino acid residues 7-27, 49-68, 84-103, 139-157, 163-182, 184-207, 237-259, 272- 294, 326-348, 377-399, 403-430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119-137, 138-160, 161-325, 326-354, 355-370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6; (g) is the complement of the nucleotide sequence of (f); (h) encodes a polypeptide having the full length amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6, except that it lacks one or more of the domains selected from the group consisting of an extracellular domain, a transmembrane domain, and an intracellular domain; or (i) is the complement of the nucleotide sequence of (h). The nucleic acid molecule of the invention is isolated, enriched, or purified from, preferably, a mammal, or most preferably from a human.

In yet other preferred embodiments the nucleic acid is an isolated conserved or unique region, for example those useful for the design of hybridization probes to facilitate identification and cloning of additional polypeptides, or for the design of PCR probes to facilitate cloning of additional polypeptides.

By "conserved nucleic acid regions", it is meant regions present on two or more nucleic acids encoding an OMA polypeptide, to which a particular nucleic acid sequence can hybridize under lower stringency conditions. Examples of lower stringency conditions suitable for screening for nucleic acids encoding OMA polypeptides are provided in Abe, et al. J. Biol. Chem. 19:13361 (1992) (hereby incorporated by reference herein in its entirety, including any drawings). Preferably, conserved regions differ by no more than 5 out of 20 contiguous nucleotides.

By "unique nucleic acid region" is meant a sequence present in a full length nucleic acid coding for an OMA polypeptide that is not present in a sequence coding for any other known naturally occurring polypeptide. Such regions preferably comprise 14, 17, 21 or more contiguous nucleotides present in the full length nucleic acid encoding an OMA polypeptide. In particular, a unique nucleic acid region is preferably of human origin.

In yet another aspect, the invention relates to a nucleic acid vector comprising a nucleic acid molecule encoding an OMA polypeptide and a promoter element effective to initiate transcription in a host cell.

The term "nucleic acid vector" relates to a single or double stranded circular nucleic acid molecule that can be transfected or transformed into cells and replicate independently or within the host cell genome. A circular double stranded nucleic acid molecule can be cut and thereby linearized upon treatment with restriction enzymes. An assortment of vectors, restriction enzymes, and the knowledge of the nucleotide sequences that the restriction enzymes operate upon are readily available to those skilled in the art. A nucleic acid molecule of the invention can be inserted into a vector by cutting the vector with restriction enzymes and ligating the two pieces together.

Many techniques are available to those skilled in the art to facilitate transformation or transfection of the expression construct into a prokaryotic or eukaryotic organism. The terms "transformation" and "transfection" refer to methods of inserting an expression construct into a cellular organism. These methods involve a variety of techniques, such as treating the cells with high concentrations of salt, an electric field, or detergent, to render the host cell outer membrane or wall permeable to nucleic acid molecules of interest. The term "promoter element" describes a nucleotide sequence that is incorporated into a vector that, once inside an appropriate cell, can facilitate transcription factor and/or polymerase binding and subsequent transcription of portions of the vector DNA into mRNA. The promoter element precedes the 5' end of the OMA polypeptide nucleic acid molecule such that the latter is transcribed into mRNA. Host cell machinery then translates mRNA into a polypeptide.

Those skilled in the art would recognize that a nucleic acid vector can contain many other nucleic acid elements besides the promoter element and the OMA nucleic acid molecule. These other nucleic acid elements include, but are not limited to, origins of replication, ribosomal binding sites, nucleic acid sequences encoding drug resistance enzymes or amino acid metabolic enzymes, and nucleic acid sequences encoding secretion signals, periplasm or peroxisome localization signals, or signals useful for polypeptide purification.

The invention also features a nucleic acid probe for the detection of a nucleic acid encoding an OMA polypeptide in a sample. The term "nucleic acid probe" refers to a nucleic molecule that is complementary to and can bind a nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or encoding the amino acid sequence substantially similar to that set forth in SEQ ID NO:5 or SEQ ID NO:6. The nucleic acid probe contains nucleic acid that will hybridize specifically to a sequence of at least 14, preferably 17, 20 or 22, continguous nucleotides set forth in SEQ

ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4 or a functional derivative thereof. The probe is preferably at least 14, 17 or more bases in length and selected to hybridize specifically to a unique region of an OMA endocing nucleic acid.

In preferred embodiments the nucleic acid probe hybridizes to nucleic acid encoding at least 14 contiguous amino acids of the full-length sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4 or a functional derivative thereof. Various low or high stringency hybridization conditions may be used depending upon the specificity and selectivity desired. Under highly stringent hybridization conditions only highly complementary nucleic acid sequences hybridize. Preferably, such conditions prevent hybridization of nucleic acids having 1 or 2 mismatches out of 20 contiguous nucleotides.

Methods for using the probes include detecting the presence or amount of OMA polypeptide RNA in a sample by contacting the sample with a nucleic acid probe under conditions such that hybridization occurs and detecting the presence or amount of the probe bound to OMA polypeptide RNA. The nucleic acid duplex formed between the probe and a nucleic acid sequence coding for an OMA polypeptide may be used in the identification of the sequence of the nucleic acid detected (for example see, Nelson et al., in Nonisotopic DNA Probe Techniques, p. 275 Academic Press, San Diego (Kricka, ed., 1992) hereby incorporated by reference herein in its entirety, including any drawings). Kits for performing such methods may be constructed to include a container having disposed therein a nucleic acid probe.

Another feature of the invention is a nucleic acid molecule as set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4 or fragments thereof, comprising one or more regions that encode an OMA polypeptide or an OMA domain polypeptide, where the OMA polypeptide or the OMA domain polypeptide is fused to a non-OMA polypeptide. Such fused polypeptides include, for example, but are not limited to, a GST- fusion protein. The invention also features recombinant nucleic acid, preferably in a cell or an organism. The recombinant nucleic acid may contain a sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4 or a functional derivative thereof and a vector or a promoter effective to initiate transcription in a host cell. The recombinant nucleic acid can alternatively contain a transcriptional initiation region functional in a cell, a sequence complimentary to an RNA sequence encoding an OMA polypeptide and a transcriptional termination region functional in a cell. Another aspect of the invention relates to a recombinant cell or tissue comprising a nucleic acid molecule encoding an OMA polypeptide. The recombinant cell may comprise a nucleic acid molecule encoding either an OMA polypeptide; an OMA domain polypeptide; or an OMA polypeptide or OMA domain polypeptide fused to a non-OMA polypeptide.

The term "recombinant organism" refers to an organism that has a new combination of genes or nucleic acid molecules. A new combination of genes or nucleic acid molecules can be introduced to an organism using a wide array of nucleic acid manipulation techniques available to those skilled in the art. The term "organism" relates to any living being comprised of a least one cell. An organism can be as simple as one eukaryotic cell or as complex as a mammal. Therefore, a recombinant organism can also be a recombinant cell, which may be a eukaryotic or a prokaryotic organism.

The term "eukaryote" refers to an organism comprised of cells that contain a nucleus. Eukaryotes are differentiated from "prokaryotes" which do not have a nucleus and lack other cellular structures found in eukaryotes, such as mitochondria and endoplasmic reticulum. Prokaryotes include unicellular organisms, such as bacteria, while eukaryotes are represented by yeast, invertebrates, and vertebrates.

The recombinant cell can harbor a nucleic acid vector that is extragenomic. The term "extragenomic" refers to a nucleic acid vector which does not insert into the cell genome. Many nucleic acid vectors are designed with their own origins of replication allowing them to utilize the recombinant cell replication machinery to copy and propagate the vector nucleic acid sequence. These vectors are small enough that they are not likely to harbor nucleic acid sequences homologous to genomic sequences of the recombinant cell. Thus these vectors replicate independently of the host genome and do not recombine with or integrate into the genome.

A recombinant cell can harbor a portion of a nucleic acid vector in an intragenomic fashion. The term "intragenomic" defines a nucleic acid construct that is incorporated within the cell genome. Multiple nucleic acid vectors available to those skilled in the art contain nucleic acid sequences that are homologous to nucleic acid sequences in a particular organism's genomic DNA. These homologous sequences will result in recombination events that integrate portions of the vector into the genomic DNA. Those skilled in the art can control which nucleic acid sequences of the vector are integrated into the cell genome by flanking the portion to be incorporated into the genome with homologous sequences in the vector.

Another aspect of the invention features an isolated, enriched, or purified OMA polypeptide. By "isolated" in reference to a polypeptide is meant a polymer of 6, 12, 18 or more amino acids conjugated to each other, including polypeptides that are isolated from a natural source or that are synthesized. The isolated polypeptides of the present invention are unique in the sense that they are not found in a pure or separated state in nature. Use ofthe term "isolated" indicates that a naturally occurring sequence has been removed from its normal cellular environment. Thus, the sequence may be in a cell-free solution or placed in a different cellular environment. The term does not imply that the sequence is the only amino acid chain present, but that it is essentially free (about 90-95% pure at least) of material naturally associated with it. By the use ofthe term "enriched" in reference to a polypeptide it is meant that the specific amino acid sequence constitutes a significantly higher fraction (2-5 fold) of the total of amino acid sequences present in the cells or solution of interest than in normal or diseased cells or in the cells from which the sequence was taken. This could be caused by a person by preferential reduction in the amount of other amino acid sequences present, or by a preferential increase in the amount of the specific amino acid sequence of interest, or by a combination of the two. However, it should be noted that "enriched" does not imply that there are no other amino acid sequences present, just that the relative amount of the sequence of interest has been significantly increased.

The term "significant" here is used to indicate that the level of increase is useful to the person making such an increase, and generally means an increase relative to other amino acid sequences of about at least 2 fold, more preferably at least 5 to 10 fold or even more. The term also does not imply that there are no amino acid sequences from other sources. The other source amino acid sequences may, for example, comprise amino acid sequences encoded by a yeast or bacterial genome, or a cloning vector such as pUC19. The term is meant to cover only those situations in which a person has intervened to elevate the proportion ofthe desired amino acid sequences.

It is also advantageous for some purposes that an amino acid sequence be in purified form. The term "purified" in reference to a polypeptide does not require absolute purity (such as a homogeneous preparation); instead, it represents an indication that the sequence is relatively purer than in the natural environment (compared to the natural level this level should be at least 2-5 fold greater, e.g., in terms of mg/mL). Purification of at least one order of magnitude, preferably two or three orders, and more preferably four or five orders of magnitude is expressly contemplated. The substance is preferably free of contamination at a functionally significant level, for example 90%, 95%, or 99% pure. In another aspect the invention features an isolated, enriched, or purified OMA polypeptide fragment, for example, an OMA domain. By "an OMA polypeptide fragment" it is meant an amino acid sequence that is less than the full-length OMA amino acid sequences encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6. Examples of fragments include OMA domains, OMA mutants and OMA-specific epitopes. Thus, the term "fragment" is used to indicate a polypeptide derived from the amino acid sequence of the OMA polypeptides, of the complexes having a length less than the full-length polypeptide from which it has been derived. Such a fragment may, for example, be produced by proteolytic cleavage of the full-length protein. Preferably, the fragment is obtained recombinantly by appropriately modifying the DNA sequence encoding the proteins to delete one or more amino acids at one or more sites of the C-terminus, N-terminus, and/or within the native sequence. Fragments of a protein are useful for screening for compounds that act to modulate signal transduction, as described herein. It is understood that such fragments may retain one or more characterizing portions of the native complex. Examples of such retained characteristics include: catalytic activity; substrate specificity; interaction with other molecules in the intact cell; regulatory functions; or binding with an antibody specific for the native complex, or an epitope thereof.

By "an OMA domain" it is meant a portion of the OMA polypeptide having homoiogy to amino acid sequences from one or more known proteins wherein the sequence predicts some common function, interaction or activity. Well known examples of domains are the SH2 (Src Homoiogy 2) domain (Sadowski, et al., Mol. Cell. Biol. 6:4396, 1986; Pawson and Schlessinger, Curr. Biol. 3:434, 1993), the SH3 domain (Mayer, et al., Nature 332:272, 1988; Pawson and Schlessinger, Curr. Biol. 3:434, 1993), and pleckstrin (PH) domain (Ponting, 27RS 21:245, 1996; Haslam, et al., Nature 363:309, 1993), all of which are domains that mediate protein :protein interaction, and the kinase catalytic domain (Hanks and Hunter, FASEB J 9:576-595, 1995). Computer programs designed to detect such homologies are well known in the art. The relative homoiogy is at least 20%, more preferably at least 30% and most preferably at least 35%.

Another aspect of the invention features an isolated, enriched or purified OMA polypeptide analog. By "OMA polypeptide analog" it is meant an amino acid sequence substantially similar to the sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6. A sequence that is substantially similar will preferably have at least 90% identity (more preferably at least 95% and most preferably 99-100%) to the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6. The OMA polypeptide analogs of the present invention preferably have a substantially similar biological activity to the proteins encoded by the full length nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4 or to the polypeptides with amino acid sequence encoded by the nucleic acid sequence set 5 forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO: 5 or SEQ ID NO:6. By "biological activity" it is meant an activity of the OMA polypeptides in a cell. The biological activity of the OMA polypeptides is related to some of the activities of the cell which include, but are not limited to, cell proliferation motogenesis, metastasis, tumor escape, cell adhesion, 0 transformation, or apoptosis.

By "identity" is meant a property of sequences that measures their similarity or relationship. Identity is measured by dividing the number of identical residues in the two sequences by the total number of residues and multiplying the product by 100. Thus, two copies of exactly the same sequence have 100% identity, but sequences that are less highly 5 conserved and have deletions, additions, or replacements have a lower degree of identity. Those skilled in the art will recognize that several computer programs are available for determining sequence identity.

An OMA polypeptide analog may which differ from the native sequence of an OMA polypeptide in that one or more amino acids have been changed, added or deleted. 0 Changes in amino acids may be conservative or non-conservative. By "conservative" it is meant the substitution of an amino acid for one with similar properties such as charge, hydrophobicity, structure, etc. Examples of polypeptides encompassed by this term include, but are not limited to, (1) chimeric proteins which comprise a portion of an OMA polypeptide sequence fused to a non-OMA polypeptide sequence, for example a 5 polypeptide sequence of glutathione-S-transferase (GST), (2) OMA polypeptides lacking a specific domain, for example the catalytic domain, and (3) OMA proteins having a point mutation. An OMA polypeptide analog will retain some useful function such as, for example, ligand binding, catalytic activity, or the ability to bind to an OMA specific antibody (as defined below). ##The OMA polypeptide analog may be derived from a 0 naturally occurring complex component by appropriately modifying the protein DNA coding sequence to add, remove, and/or to modify codons for one or more amino acids at one or more sites of the C-terminus, N-terminus, and/or within the native sequence. It is understood that such analogs having added, substituted and/or additional amino acids retain one or more characterizing portions ofthe native OMA polypeptides.

^"^ OMA polypeptide analogs with deleted, inserted and/or substituted amino acid

.sidues may be prepared using standard techniques well-known to those of ordinary skill the art. For example, the modified components of the analogs may be produced using site-directed mutagenesis techniques (as exemplified by Adelman et al., 1983, DNA 2:183) wherein nucleotides in the DNA coding the sequence are modified such that a modified coding sequence is produced, and thereafter expressing this recombinant DNA in a prokaryotic or eukaryotic host cell, using techniques such as those described above. Alternatively, proteins with amino acid deletions, insertions and/or substitutions may be conveniently prepared by direct chemical synthesis, using methods well-known in the art. The analogs of the OMA polypeptides may exhibit the same qualitative biological activity as the OMA polypeptides themselves.

By "OMA-specific epitope" it is meant a sequence of amino acids that is both antigenic and unique to OMA. OMA-specific epitope can be used to produce OMA- specific antibodies, as more fully described below.

By "recombinant OMA polypeptide" it is meant to include a polypeptide produced by recombinant DNA techniques such that it is distinct from a naturally occurring polypeptide either in its location (e.g., present in a different cell or tissue than found in nature), purity or structure. Generally, such a recombinant polypeptide will be present in a cell in an amount different from that normally observed in nature.

The polypeptide of the invention comprises an amino acid sequence having (a) the full length amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6; (b) the full length amino acid sequence of the sequence set forth in SEQ ID NO:5 or SEQ ID NO:6, except that it lacks one or more of the following segments of amino acid residues: 7-27, 49-68, 84-103, 139-157, 163-182, 184- 207, 237-259, 272-294, 326-348, 377-399, 403-430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119-137, 138-160, 161-325, 326-354, 355- 370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6; (c) the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6 from amino acid residues, 7-27, 49- 68, 84-103, 139-157, 163-182, 184-207, 237-259, 272-294, 326-348, 377-399, 403-430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119- 137, 138-160, 161-325, 326-354, 355-370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6; or (d) the full length amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO: 6 except that it lacks one or more of the domains selected from the group consisting of an extracellular domain, a transmembrane domain, and an intracellular domain.

The OMA polypeptides, or fragments thereof, of the present invention are preferably isolated, purified, or enriched from a mammal or a mammalian cell. The mammal is as defined herein and preferably is a mouse, and most preferably is a human. These polypeptides may be isolated, purified, or enriched from a cell that comprises an endogenous nucleic acid molecule that encodes the polypeptide, or from a cell that is transformed with a nucleic acid molecule that encodes the polypeptide. The polypeptide may also be chemically synthesized. Procedures for obtaining polypeptides using the above methods are well known to those skilled in the art. In yet another aspect the invention features an antibody (e.g., a monoclonal or polyclonal antibody) having specific binding affinity to an OMA polypeptide or OMA polypeptide analog or fragment. By "specific binding affinity" is meant that the antibody binds to target (OMA) polypeptides with greater affinity than it binds to other polypeptides under specified conditions. Antibodies having specific binding affinity to an OMA polypeptide may be used in methods for detecting the presence and/or amount of an OMA polypeptide in a sample by contacting the sample with the antibody under conditions such that an immunocomplex forms and detecting the presence and/or amount of the antibody conjugated to the OMA polypeptide. Diagnostic kits for performing such methods may be constructed to include a first container containing the antibody and a second container having a conjugate of a binding partner of the antibody and a label, such as, for example, a radioisotope. The diagnostic kit may also include notification of an FDA approved use and instructions therefor.

The term "polyclonal" refers to antibodies that are heterogenous populations of antibody molecules derived from the sera of animals immunized with an antigen or an antigenic functional derivative thereof. For the production of polyclonal antibodies, various host animals may be immunized by injection with the antigen. Various adjuvants may be used to increase the immunological response, depending on the host species.

"Monoclonal antibodies" are substantially homogenous populations of antibodies to a particular antigen. They may be obtained by any technique which provides for the production of antibody molecules by continuous cell lines in culture. Monoclonal antibodies may be obtained by methods known to those skilled in the art. See, for example, Kohler, et al., Nature 256:495-497 (1975), and U.S. Patent No. 4,376,110.

The term "antibody fragment" refers to a portion of an antibody, often the hypervariable region and portions of the surrounding heavy and light chains, that displays specific binding affinity for a particular molecule. A hypervariable region is a portion of an antibody that physically binds to the polypeptide target.

In another aspect the invention features a hybridoma which produces an antibody having specific binding affinity to an OMA polypeptide. By "hybridoma" is meant an immortalized cell line which is capable of secreting an antibody, for example an OMA antibody. In preferred embodiments the OMA antibody comprises a sequence of amino acids that is able to specifically bind an OMA polypeptide. The invention features a method for identifying human cells containing an OMA polypeptide or a related sequence. The method involves identifying the novel polypeptide in human cells using techniques that are routine and standard in the art, such as those described herein for identifying OMA (e.g., cloning, Southern or Northern blot analysis, Western blot analysis, immunoassay, in situ hybridization, PCR amplification, etc.).

The invention also features methods of screening cells for natural binding partners of OMA polypeptides. By "natural binding partner" it is meant a protein that interacts with an OMA polypeptide. Binding partners include agonists, antagonists and downstream signaling molecules such as adaptor proteins and may be identified by techniques well known in the art such as co-immunoprecipitation or by using, for example, a two-hybrid screen. (Fields and Song, U.S. Patent No. 5,283,173, issued February 1, 1994 and, incorporated by reference herein.) The present invention also features the purified, isolated or enriched versions of the polypeptides identified by the methods described above. In another aspect, the invention provides a method for identifying a substance capable of modulating OMA polypeptide activity comprising the steps of (a) contacting an OMA polypeptide with a test substance; and (b) determining whether the substance alters the activity of said polypeptide.

The invention also features another method of identifying substances capable of modulating the function of a OMA polypeptide. The method comprises the following steps: (a) expressing an OMA polypeptide in cells; (b) adding a compound to the cells; and (c) monitoring a change or an absence of a change in cell phenotype, cell proliferation, catalytic activity ofthe OMA polypeptide, and binding a natural binding partner.

The term "compound" includes small organic or inorganic molecules of molecular weight of preferably less than 1000 atomic units, more preferably less than 800 atomic units, and most preferably less than 500 atomic units. "Organic molecules" include all molecules that contain a carbon atom, whereas "inorganic molecules" are those that do not have a carbon atom.

The term "function" refers to the cellular role of a protein. The role of the proteins of the invention may include regulation of the many steps in signaling cascades, including cascades controlling cell growth, migration, differentiation, gene expression, muscle contraction, glucose metabolism, cellular protein synthesis, and regulation of the cell cycle.

The term "modulates" refers to the ability of a compound to alter the function of a protein. A modulator preferably activates the catalytic activity of a protein, more preferably activates or inhibits the catalytic activity of a protein depending on the concentration of the compound exposed to the protein, or most preferably inhibits the catalytic activity of a protein. The term "modulates" also refers to altering the function of a protein by increasing or decreasing the probability that a complex, i.e. an assembly of at least two molecules bound to one another, forms between a protein and a natural binding partner. A modulator preferably increases the probability that such a complex forms between the protein and the natural binding partner, more preferably increases or decreases the probability that a complex forms between the protein and the natural binding partner depending on the concentration of the compound exposed to the protein, and most preferably decreases the probability that a complex forms between the protein and the natural binding partner. The term "catalytic activity," in the context of the invention, defines the ability of a protein to react with a substrate. Catalytic activity can be measured, for example, by determining the amount of a substrate converted to a product as a function of time. Reaction with a substrate occurs at the active-site of a protein.

The term "substrate" as used herein refers to a molecule that is reacted on by or directly interacts with the protein of the invention. The substrate may be a small organic molecule, a peptide, or a protein.

The term "activates" refers to increasing the cellular function of a protein, while the term "inhibit" refers to decreasing the cellular function of a protein. The protein function is preferably the interaction with a natural binding partner or catalytic activity. The term "expressing" as used herein refers to the production of an OMA polypeptide from a nucleic acid vector containing an OMA gene within a cell. The nucleic acid vector is transfected into cells using well known techniques in the art as described herein.

The term "adding" as used herein refers to administering a solution comprising a compound to the medium bathing cells. The solution comprising the compound can also comprise an agent, such as dimethylsulfoxide, which facilitates the uptake of the compound into the cells.

The term "monitoring" refers to observing the effect of adding the compound to the cells of the method. The effect can be manifested in a change in cell phenotype, cell proliferation, protein catalytic activity, or in the interaction between a protein and a natural binding partner.

The term "cell phenotype" refers to the outward appearance of a cell or tissue or the function of the cell or tissue. Examples of cell or tissue phenotype are cell size (reduction or enlargement), cell proliferation (increased or decreased numbers of cells), cell differentiation (a change or absence of a change in cell shape), cell survival, apoptosis (cell death), or the utilization of a metabolic nutrient (e.g., glucose uptake). Change or the absence of change in cell phenotype is readily measured by techniques known in the art. The term "cell proliferation" refers to the rate at which a group of cells divides.

The number of cells growing in a vessel can be quantitated by a person skilled in the art when that person visually counts the number of cells in a defined area using a common light microscope. Alternatively, cell proliferation rates can be quantified by laboratory apparatuses that optically measure the density of cells in an appropriate medium.

The methods of the present invention can utilize any of the molecules disclosed in the invention. These molecules include nucleic acid molecules encoding OMA polypeptides, nucleic acid vectors, recombinant cells, polypeptides, or antibodies described herein. The invention also provides for a method of diagnosing a disorder of fuel metabolism in an individual, comprising detection of a gene transcript level. The gene preferably encodes an OMA polypeptide, selected from the group consisting of P4P6B1, P7P7C1, P10P10C5, and P6P7A. The gene transcript level is induced or repressed in the individual by a factor selected from the group consisting of genetic obesity, fasting, and refeeding of a fasted individual. The individual intended by this method is a mammal, preferably a mouse, and most preferably a human, and is selected from the group consisting of an underweight individual and an overweight individual.

"Disorders of fuel metabolism" are abnormalities in metabolism which lead to alterations in the manner in which an individual stores and metabolizes (breaksdown) cholesterol, protein and fat, including body weight disorders, which cause an individual to have a weight below or above the normal weight for the individual in the individual's weight and height group. For example, abnormally underweight or abnormally overweight individuals are said to have disorders of fuel metabolism. There are numerous causes for body weight disorders of fuel metabolism which include, but are not limited to, genetic obesity, diabetes, fasting, and refeeding of a fasted individual. "Genetic obesity" refers to the condition of being overweight because of an individual's genetic makeup. Fasting and fasting followed by refeeding may also cause obesity in individuals. The diagnosis of a disorder of fuel metabolism in an individual caused by any one of these factors or other factors is within the scope ofthe present invention. In a preferred embodiment, the invention provides a method for treating or preventing an abnormal condition by administering a therapeutically effective amount of a compound which is an in vitro modulator of an OMA polypeptide function. The abnormal condition preferably involves abnormality in OMA polypeptide cellular activity, more preferably is a disorder of fuel metabolism, and most preferably is a body weight disorder, such as obesity. Such compounds preferably show positive results in one or more in vitro assays for an activity corresponding to treatment of the disease or disorder in question. The modulator of OMA polypeptide function is preferably an inhibitor of the protein and more preferably is an antisense oligonucleotide that inhibits the expression of said polypeptide. The antisense oligonucleotide is preferably the complement of a sequence encoding a fragment of a protein encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6.

The invention also provides for a method for detection of a nucleic acid encoding an OMA polypeptide in a sample as a diagnostic tool for a disorder of fuel metabolism, where the method comprises (a) contacting the sample with a nucleic acid probe which hybridizes under hybridization assay conditions to a nucleic acid target region of the OMA polypeptide, the probe comprising the nucleic acid sequence encoding the OMA polypeptide, fragments thereof, and the complements of the sequences and fragments; and (b) detecting the presence or amount of the probe:target region hybrid as an indication of the disorder of fuel metabolism.

The summary of the invention described above is non-limiting and other features and advantages of the invention will be apparent from the following detailed description, and from the claims.

Brief Description Of The Figures

Figure 1 shows the Northern blot of radiolabeled cDNA fragment of P4P6B1 hybridized to total RNA from retroperitoneal fat (retrofat), liver, pancreas, brain and skeletal muscle from NIH-Swiss (NIH), db/db, GTG-treated NIH-Swiss (NIH GTG) and ob/ob mice.

Figure 2 shows the sequence of cDNA fragment of P4P6B1. Figure 3 shows the P4P6B1 cDNA sequence with translation of the proposed coding region and the original 450 bp PCR fragment underlined. Figure 4 shows the P4P6B1 polypeptide analysis.

Figure 5 shows the BLASTP analysis ofthe P4P6B1 protein. Figure 6 shows the TMPred-prediction of transmembrane regions and orientation. Figure 7 shows the Northern blot of radiolabeled cDNA fragment of P7P7C1 hybridized to total RNA from retroperitoneal fat (RT), brain (B), liver (L), muscle (M) and pancreas (P) from NIH-Swiss (NIH), GTG-treated NIH-Swiss (GTG), db/db and ob/ob mice.

Figure 8 is the sequence of cDNA fragment P7P7C1.

Figure 9 is the Sequence of the murine C3a receptor cDNA (Genbank accession #U77460) with translation of the coding region. The P7P7C1 cDNA fragment is underlined. Figure 10 shows the Northern blot of radiolabeled cDNA fragment of P10P10C5 hybridized to total RNA from retroperitoneal fat (RT), brain (B), liver (L), muscle (M) and pancreas (P) from NIH-Swiss (NIH), GTG-treated NIH-Swiss (GTG), db/db and ob/ob mice. Figure 11 is the sequence of cDNA fragment P 1 OP 10C5.

Figure 12 shows the P10P10C5 BLASTX search results. The P10P10C5 cDNA sequence (figure 7) translated in all reading frames was compared against the non- redundant protein database.

Figure 13 shows the Northern blot of radiolabeled cDNA fragment of P6P7A hybridized to total RNA from retroperitoneal fat (R), liver (L), pancreas (P), brain (B), and muscle (M) from NIH-Swiss (NIH), GTG-treated NIH-Swiss (GTG), db/db (Db), and ob/ob (Ob) mice.

Figure 14 shows the P6P7A sequence of the 5' and 3' terminal ends of the 440 bp cDNA fragment. Figure 15 shows the consensus sequences of P6P7A cDNA. The bold, underlined sequence represents the oligonucleotide used for GeneTrapper™ cloning.

Figure 16 shows the results of a BLASTX search of the non-redundant protein databases using the consensus P6P7A sequence as the search query.

Detailed Description Of The Invention

L The OMA Polypeptides ofthe Invention

a) P4P6B1

A 450 bp cDNA fragment, designated P4P6B1, was generated by RNA fingerprinting using random primers P4 and P6. The P4P6B1 fragment corresponds to a message upregulated in the retroperitoneal fat of all of the obese mouse models: GTG- Swiss, db/db and ob/ob. To confirm its differential expression, the 450 bp cDNA fragment was PCR labeled and used as a probe on a Northern blot containing total RNA from retroperitoneal fat, brain, liver, muscle, and pancreatic tissues from all four mouse models (see Figure 1). The labeled P4P6B1 fragment hybridized to a -4.5 kbp mRNA species that is predominantly expressed in retroperitoneal fat and upregulated in the obese mouse models, especially the db/db and ob/ob animals.

The 450 bp P4P6B1 fragment was sequenced (see Figure 2) and compared with various sequence databases, at both the nucleotide and amino acid levels, using the BLAST (Altschul, S. F., et al. Nucleic Acids Res. 25:3389-3402, 1997; Karlin, S., et al, PNAS USA 87:2264-68, 1990; Karlin, S., et al, PNAS USA 90:5873-7, 1993) set of programs available from the National Center for Biotechnology Information (NCBI). There was no significant similarity between the 450 bp P4P6B1 fragment and any sequence contained within the databases.

A combination of GeneTrapper™ cloning (GIBCO/Life Technologies, Bethesda, Maryland) and 5' RACE ( GIBCO/Life Technologies, Bethesda, Maryland) was employed to molecularly clone the entire coding region sequence corresponding to partial cDNA fragment P4P6B1. The deduced protein (see Figure 3) consists of 580 amino acids with a calculated molecular weight of 63330.05 daltons (see Figure 4). The first twenty-five residues are predicted to comprise a cleavable N-terminal signal sequence (SignalP program, EXPASY, Geneva, Switzerland; Nielsen, H., et al.: Identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites. Protein Engineering, 10, 1-6 (1997)).

The entire amino acid sequence of P4P6B1 was analyzed through the NCBI Blast programs. Significant similarities to the sodium:solute symporter family of proteins were obtained (see Figure 5). Members of this family of proteins contain a motif of twelve hydrophobic membrane-spanning domains. The amino acid sequence of P4P6B1 is predicted (TMPred, ISREC Bioinformatics Group, Lausanne, Switzerland; K. Hofmann and W. Stoffel, Biol. Chem. Hoppe-Seyler 347:166 (1993)) to contain thirteen potential membrane spanning hydrophobic regions, the first of which corresponding to the predicted N-terminal signal sequence, leaving twelve possible transmembrane domains (see Figure 6).

b) P7P7C1

A 485 bp cDNA fragment, designated P7P7C1, was generated by RNA fingerprinting using random primer P7. The P7P7C1 fragment corresponds to a message upregulated in the retroperitoneal fat of all ofthe obese mouse models: GTG-Swiss, db/db, and ob/ob. To confirm its differential expression, the 485 bp P7P7C1 cDNA fragment was PCR labeled and used as a probe on a Northern blot containing total RNA from retroperitoneal fat, brain, liver, muscle, and pancreatic tissues from all four mouse models (see Figure 7). The labeled P7P7C1 fragment hybridizes to a -4.0 kbp mRNA species that is predominantly expressed in the retroperitoneal fat and upregulated in the obese mouse models.

The 485 bp P7P7C1 fragment was sequenced (see Figure 8) and compared with various sequence databases, at both the nucleotide and amino acid level, using the BLAST (Altschul, S. F., et al. Nucleic Acids Res. 25:3389-3402, 1997; Karlin, S., et al, PNAS USA 87:2264-68, 1990; Karlin. S., et al, PNAS USA 90:5873-7, 1993) set of programs available from the National Center for Biotechnology Information (NCBI). The fragment is 100% homologous to a region in the 3' untranslated portion of the murine C3a receptor cDNA (Genbank Accession number = U77460) (see Figure 9). The murine C3a receptor is a seven transmembrane G-protein coupled receptor and its corresponding ligand, C3a, has been extensively characterized as an immune response mediator. C3a receptor gene expression is upregulated in the retroperitoneal fat of the obese mice and, therefore, implicates C3a and analogs, in concert with the receptor, as having a novel role in adipocyte cell biology.

c) P10P10C5

A 750 bp cDNA fragment, designated P10P10C5, was generated by RNA fingerprinting using random primer P10. The P10P10C5 fragment corresponds to a message upregulated in the retroperitoneal fat of all of the obese mouse models: GTG- Swiss, db/db, and ob/ob. To confirm its differential expression, the 750 bp P10P10C5 cDNA fragment was PCR labeled and used as a probe on a Northern blot containing total RNA from retroperitoneal fat, brain, liver, muscle, and pancreatic tissues from all four mouse models (see Figure 10). The labeled P10P10C5 fragment hybridized to a mRNA species greater than 9.0 kbp and is predominantly expressed in the retroperitoneal fat and upregulated in the obese mouse models.

The 750 bp P10P10C5 cDNA fragment was sequenced (see Figure 11) and compared with various sequence databases, at both the nucleotide and amino acid levels, using the BLAST (Altschul, S. F., et al, Nucleic Acids Res. 25:3389-3402, 1997; Karlin, S., et al, PNAS USA 87:2264-68, 1990; Karlin, S., et al, PNAS USA 90:5873-7, 1993) set of programs available from the National Center for Biotechnology Information (NCBI). The fragment contains at least two Epidermal-Like Growth Factor (EGF) domains and is similar to the Motch/Notch family of proteins (see Figure 12). Members of this family are large transmembrane proteins containing a number of EGF-like domains and are implicated in control of cell growth and differentiation. A soluble EGF-like domain from a similar protein, PREF-1, was demonstrated to have an inhibitory effect on the growth and differentiation of adipocytes (Smas, C. M., et al., Mol. Cell. Biology 1997(Feb) 17(2) 977-988). P10P10C5 may also have a novel role in the growth and differentiation of adipocytes and be a factor in the etiology of obesity.

d) P6P7A

A cDNA fragment, approximately 440 bp long, was generated by RNA fingerprinting using random primers P6 and P7 and was designated P6P7A. The P6P7A fragment corresponds to a message upregulated in the retroperitoneal fat and liver of all of the obese mouse models: GTG-Swiss, db/db, and ob/ob. To confirm its differential expression, the 440 bp P6P7A cDNA fragment was PCR labeled and used as a probe on a Northern blot containing total RNA from retroperitoneal fat, brain, liver, muscle, and pancreatic tissues from all four mouse models (see Figure 13). The labeled P6P7A fragment hybridizes to a -2.4 kbp mRNA species that is predominantly expressed in the retroperitoneal fat and liver and is upregulated in the obese mouse models.

The 5' and 3 '-terminal ends of the 440 bp P6P7A cDNA fragment were sequenced (see Figure 14) and compared with various databases, at both the nucleotide and amino acid level, using the BLAST (Altschul, S. F., et al, Nucleic Acid Res. 25:3389-3402, 1997; Karlin, S., et al, PNAS USA 87:2264-68, 1990; Karlin, S., et al, PNAS USA 90:5873-7, 1993) set of programs available from the National Center for Biotechnology Information (NCBI). No significant homologous sequences were identified in the non-redundant nucleotide or protein databases. The available sequence information was used to design the oligonucleotide to proceed with GeneTrapper™ cloning.

GeneTapper™ cloning (GIBCO/Life Technologies, Bethesda, Maryland) was employed to molecularly clone a longer region of sequence corresponding to the P6P7A partial cDNA fragment. Two identical clones -1.9 kbp, A881-1 and A881-21, were generated and sequenced. The combined sequence information (see Figure 15) from the new clones and the 450 bp cDNA fragment was analyzed at both the nucleotide and amino acid level, using the BLAST (Altschul, S. F., et al, Nucleic Acid Res. 25:3389-3402, 1997; Karlin, S., et al, PNAS USA 87:2264-68, 1990; Karlin, S., et al, PNAS USA 90:5873-7, 1993) set of programs available from the National Center for Biotechnology Information (NCBI). P6P7a has significant homoiogy to the lectin-like oxidized LDL receptors and other members ofthe C-type lectin family of membrane proteins (see Figure 16).

II. Nucleic Acid Probes. Methods, and Kits for Detection ofthe OMA Polypeptides A nucleic acid probe of the present invention may be used to probe an appropriate chromosomal or cDNA library by usual hybridization methods to obtain other nucleic acid molecules of the present invention. A chromosomal DNA or cDNA library may be prepared from appropriate cells according to recognized methods in the art (cf. "Molecular Cloning: A Laboratory Manual", second edition, Cold Spring Harbor Laboratory, Sambrook, Fritsch, & Maniatis, eds., 1989).

In the alternative, chemical synthesis can be carried out in order to obtain nucleic acid probes having nucleotide sequences which correspond to N-terminal and C-terminal portions of the amino acid sequence of the polypeptide of interest. The synthesized nucleic acid probes may be used as primers in a polymerase chain reaction (PCR) carried out in accordance with recognized PCR techniques, essentially according to PCR Protocols, "A Guide to Methods and Applications", Academic Press, Michael, et al., eds.. 1990, utilizing the appropriate chromosomal or cDNA library to obtain the fragment ofthe present invention.

One skilled in the art can readily design such probes based on the sequence disclosed herein using methods of computer alignment and sequence analysis known in the art ("Molecular Cloning: A Laboratory Manual", 1989, supra). The hybridization probes of the present invention can be labeled by standard labeling techniques such as with a radiolabel, enzyme label, fluorescent label, biotin-avidin label, chemiluminescence, and the like. After hybridization, the probes may be visualized using known methods.

The nucleic acid probes of the present invention include RNA, as well as DNA probes, such probes being generated using techniques known in the art. The nucleic acid probe may be immobilized on a solid support. Examples of such solid supports include, but are not limited to, plastics such as polycarbonate, complex carbohydrates such as agarose and sepharose, and acrylic resins, such as polyacrylamide and latex beads. Techniques for coupling nucleic acid probes to such solid supports are well known in the art.

The test samples suitable for nucleic acid probing methods ofthe present invention include, for example, cells or nucleic acid extracts of cells, or biological fluids. The samples used in the above-described methods will vary based on the assay format, the detection method and the nature ofthe tissues, cells or extracts to be assayed. Methods for preparing nucleic acid extracts of cells are well known in the art and can be readily adapted in order to obtain a sample that is compatible with the method utilized.

One method of detecting the presence of nucleic acids of the invention in a sample comprises (a) contacting the sample with the above-described nucleic acid probe under conditions such that hybridization occurs, and (b) detecting the presence of the probe bound to the nucleic acid molecule. One skilled in the art would select the nucleic acid probe according to techniques known in the art as described above. Samples to be tested include but should not be limited to RNA samples of human tissue.

A kit for detecting the presence of nucleic acids of the invention in a sample comprises at least one container means having disposed therein the above-described nucleic acid probe. The kit may further comprise other containers comprising one or more of the following: wash reagents and reagents capable of detecting the presence of bound nucleic acid probe. Examples of detection reagents include, but are not limited to radiolabelled probes, enzymatic labeled probes (horseradish peroxidase, alkaline phosphatase), and affinity labeled probes (biotin, avidin, or streptavidin). Preferably, the kit further comprises instructions for use.

A compartmentalized kit includes any kit in which reagents are contained in separate containers. Such containers include small glass containers, plastic containers or strips of plastic or paper. Such containers allow the efficient transfer of reagents from one compartment to another compartment such that the samples and reagents are not cross- contaminated and the agents or solutions of each container can be added in a quantitative fashion from one compartment to another. Such containers include a container that accepts the test sample, a container that contains the probe or primers used in the assay, containers that contain wash reagents (such as phosphate buffered saline, Tris-buffers, and the like), and containers that contain the reagents used to detect the hybridized probe, bound antibody, amplified product, or the like. One skilled in the art will readily recognize that the nucleic acid probes described in the present invention can readily be incorporated into one ofthe established kit formats that are well known in the art.

III. DNA Constructs Comprising a Nucleic Acid Molecule and Cells Containing These Constructs

The present invention also relates to a recombinant DNA molecule comprising, 5' to 3', a promoter effective to initiate transcription in a host cell and the above-described nucleic acid molecules. In addition, the present invention relates to a recombinant DNA molecule comprising a vector and an above-described nucleic acid molecule. The present invention also relates to a nucleic acid molecule comprising a transcriptional region functional in a cell, a sequence complementary to an RNA sequence encoding an amino acid sequence corresponding to the above-described polypeptide, and a transcriptional termination region functional in said cell. The above-described molecules may be isolated and/or purified DNA molecules.

The present invention also relates to a cell or organism that contains an above- described nucleic acid molecule and thereby is capable of expressing a polypeptide. The polypeptide may be purified from cells that have been altered to express the polypeptide. A cell is said to be "altered to express a desired polypeptide" when the cell, through genetic manipulation, is made to produce a protein which it normally does not produce or which the cell normally produces at lower levels. One skilled in the art can readily adapt procedures for introducing and expressing either genomic, cDNA, or synthetic sequences into either eukaryotic or prokaryotic cells. A nucleic acid molecule, such as DNA, is said to be "capable of expressing" a polypeptide if it contains nucleotide sequences which contain transcriptional and translational regulatory information and such sequences are "operably linked" to nucleotide sequences which encode the polypeptide. An operable linkage is a linkage in which the regulatory DNA sequences and the DNA sequence sought to be expressed are connected in such a way as to permit gene sequence expression. The precise nature of the regulatory regions needed for gene sequence expression may vary from organism to organism, but shall in general include a promoter region which, in prokaryotes, contains both the promoter (which directs the initiation of RNA transcription) as well as the DNA sequences which, when transcribed into RNA, will signal synthesis initiation. Such regions will normally include those 5'-non-coding sequences involved with initiation of transcription and translation, such as the TATA box, capping sequence, CAAT sequence, and the like.

If desired, the non-coding region 3' to the sequence encoding an OMA polypeptide of the invention may be obtained by the above-described methods. This region may be retained for its transcriptional termination regulatory sequences, such as termination and polyadenylation. Thus, by retaining the 3'-region naturally contiguous to the DNA sequence encoding an OMA polypeptide of the invention, the transcriptional termination signals may be provided. Where the transcriptional termination signals are not satisfactorily functional in the expression host cell, then a 3' region functional in the host cell may be substituted. Two DNA sequences (such as a promoter region sequence and a sequence encoding an OMA polypeptide of the invention) are said to be operably linked if the nature of the linkage between the two DNA sequences does not (1) result in the introduction of a frame-shift mutation, (2) interfere with the ability of the promoter region sequence to direct the transcription of a gene sequence encoding an OMA polypeptide of the invention, or (3) interfere with the ability ofthe gene sequence of an OMA polypeptide of the invention to be transcribed by the promoter region sequence. Thus, a promoter region would be operably linked to a DNA sequence if the promoter were capable of effecting transcription of that DNA sequence. Thus, to express a gene encoding an OMA polypeptide of the invention, transcriptional and translational signals recognized by an appropriate host are necessary.

The present invention encompasses the expression of a gene encoding an OMA polypeptide of the invention (or a functional derivative thereof) in either prokaryotic or eukaryotic cells. Prokaryotic hosts are, generally, very efficient and convenient for the production of recombinant proteins and are, therefore, one type of preferred expression system for OMA polypeptides of the invention. Prokaryotes most frequently are represented by various strains of E. coli. However, other microbial strains may also be used, including other bacterial strains.

In prokaryotic systems, plasmid vectors that contain replication sites and control sequences derived from a species compatible with the host may be used. Examples of suitable plasmid vectors may include pBR322, pUC118, pUC119 and the like; suitable phage or bacteriophage vectors may include λgtlO, λgtl l and the like; and suitable virus vectors may include pMAM-neo, pKRC and the like. Preferably, the selected vector of the present invention has the capacity to replicate in the selected host cell.

Recognized prokaryotic hosts include bacteria such as E. coli, Bacillus, Streptomyces, Pseudomonas, Salmonella, Serratia, and the like. However, under such conditions, the polypeptide will not be glycosylated. The prokaryotic host must be compatible with the replicon and control sequences in the expression plasmid.

To express an OMA polypeptide of the invention (or a functional derivative thereof) in a prokaryotic cell, it is necessary to operably link the sequence encoding the OMA polypeptide of the invention to a functional prokaryotic promoter. Such promoters may be either constitutive or, more preferably, regulatable (i.e., inducible or derepressible). Examples of constitutive promoters include the int promoter of bacteriophage λ, the bla promoter of the β-lactamase gene sequence of pBR322, and the cat promoter of the chloramphenicol acetyl transferase gene sequence of pPR325, and the like. Examples of inducible prokaryotic promoters include the major right and left promoters of bacteriophage λ (P_L and P_R), the trp, recA, cZ, λaci, and gal promoters of E. coli, the α-amylase (Ulmanen et al., J. Bacteriol. 162:176-182, 1985) and the ς-28- specific promoters of B. subtilis (Gilman et al., Gene Sequence 32:11-20, 1984), the promoters of the bacteriophages of Bacillus (Gryczan, In: The Molecular Biology of the Bacilli, Academic Press, Inc., NY, 1982), and Streptomyces promoters (Ward et al, Mol. Gen. Genet. 203:468-478, 1986). Prokaryotic promoters are reviewed by Glick (Ind. Microbiot. 1 :277-282, 1987), Cenatiempo (Biochimie 68:505-516, 1986), and Gottesman (Ann. Rev. Genet. 18:415-442, 1984).

Proper expression in a prokaryotic cell also requires the presence of a ribosome- binding site upstream of the gene sequence-encoding sequence. Such ribosome-binding sites are disclosed, for example, by Gold et al. (Ann. Rev. Microbiol. 35:365-404, 1981). The selection of control sequences, expression vectors, transformation methods, and the like, are dependent on the type of host cell used to express the gene. As used herein, "cell", "cell line", and "cell culture" may be used interchangeably and all such designations include progeny. Thus, the words "transformants" or "transformed cells" include the primary subject cell and cultures derived therefrom, without regard to the number of transfers. It is also understood that all progeny may not be precisely identical in DNA content, due to deliberate or inadvertent mutations. However, as defined, mutant progeny have the same functionality as that ofthe originally transformed cell.

Host cells which may be used in the expression systems of the present invention are not strictly limited, provided that they are suitable for use in the expression of the OMA polypeptide of interest. Suitable hosts may often include eukaryotic cells. Preferred eukaryotic hosts include, for example, yeast, fungi, insect cells, mammalian cells either in vivo, or in tissue culture. Mammalian cells which may be useful as hosts include 3T3-L1 preadipocytes, HeLa cells, cells of fibroblast origin such as VERO or CHO-K1, or cells of lymphoid origin and their derivatives. Preferred mammalian host cells include SP2/0 and J558L, as well as neuroblastoma cell lines such as IMR 332, which may provide better capacities for correct post-translational processing.

In addition, plant cells are also available as hosts, and control sequences compatible with plant cells are available, such as the cauliflower mosaic virus 35S and 19S, and nopaline synthase promoter and polyadenylation signal sequences. Another preferred host is an insect cell, for example the Drosophila larvae. Using insect cells as hosts, the Drosophila alcohol dehydrogenase promoter can be used (Rubin, Science 240:1453-1459, 1988). Alternatively, baculovirus vectors can be engineered to express large amounts of OMA polypeptides of the invention in insect cells (Jasny, Science 238:1653, 1987; Miller et al, In: Genetic Engineering, Vol. 8, Plenum, Setlow et al, eds., pp. 277-297, 1986). Any of a series of yeast expression systems can be utilized which incorporate promoter and termination elements from the actively expressed sequences coding for glycolytic enzymes that are produced in large quantities when yeast are grown in mediums rich in glucose. Known glycolytic gene sequences can also provide very efficient transcriptional control signals. Yeast provides substantial advantages in that it can also carry out post-translational modifications. A number of recombinant DNA strategies exist utilizing strong promoter sequences and high copy number plasmids which can be utilized for production of the desired proteins in yeast. Yeast recognizes leader sequences on cloned mammalian genes and secretes peptides bearing leader sequences (i.e., pre- peptides). Several possible vector systems are available for the expression of OMA polypeptides of the invention in a mammalian host.

A wide variety of transcriptional and translational regulatory sequences may be employed, depending upon the nature of the host. The transcriptional and translational regulatory signals may be derived from viral sources, such as adenovirus, bovine papilloma virus, cytomegalovirus, simian virus, or the like, where the regulatory signals are associated with a particular gene sequence which has a high level of expression. Alternatively, promoters from mammalian expression products, such as actin, collagen, myosin, and the like, may be employed. Transcriptional initiation regulatory signals may be selected which allow for repression or activation, so that expression of the gene sequences can be modulated. Of interest are regulatory signals which are temperature- sensitive so that by varying the temperature, expression can be repressed or initiated, or are subject to chemical (such as metabolite) regulation. Expression of OMA polypeptides of the invention in eukaryotic hosts requires the use of eukaryotic regulatory regions. Such regions will, in general, include a promoter region sufficient to direct the initiation of RNA synthesis. Preferred eukaryotic promoters include, for example, the promoter of the mouse metallothionein I gene sequence (Hamer et al, J. Mol. Appl. Gen. 1 :273-288, 1982); the TK promoter of Herpes virus (McKnight, Cell 31 :355-365, 1982); the SV40 early promoter (Benoist et al, Nature (London) 290:304-31, 1981); and the yeast gal4 gene sequence promoter (Johnston et al, Proc. Natl. Acad. Sci. (USA) 79:6971-6975, 1982; Silver et al, Proc. Natl. Acad. Sci. (USA) 81:5951-5955, 1984). Translation of eukaryotic mRNA is initiated at the codon which encodes the first methionine. For this reason, it is preferable to ensure that the linkage between a eukaryotic promoter and a DNA sequence which encodes an OMA polypeptide of the invention (or a functional derivative thereof) does not contain any intervening codons which are capable of encoding a methionine (i.e., AUG). The presence of such codons results either in the formation of a fusion protein (if the AUG codon is in the same reading frame as the OMA polypeptide of the invention coding sequence) or a frame-shift mutation (if the AUG codon is not in the same reading frame as the OMA polypeptide of the invention coding sequence).

A nucleic acid molecule encoding an OMA polypeptide of the invention and an operably linked promoter may be introduced into a recipient prokaryotic or eukaryotic cell either as a nonreplicating DNA or RNA molecule, which may either be a linear molecule or, more preferably, a closed covalent circular molecule. Since such molecules are incapable of autonomous replication, the expression of the gene may occur through the transient expression of the introduced sequence. Alternatively, permanent expression may occur through the integration of the introduced DNA sequence into the host chromosome.

A vector may be employed which is capable of integrating the desired gene sequences into the host cell chromosome. Cells which have stably integrated the introduced DNA into their chromosomes can be selected by also introducing one or more markers which allow for selection of host cells which contain the expression vector. The marker may provide for prototrophy to an auxotrophic host, biocide resistance, e.g., antibiotics, or heavy metals, such as copper, or the like. The selectable marker gene sequence can either be directly linked to the DNA gene sequences to be expressed, or introduced into the same cell by co-transfection. Additional elements may also be needed for optimal synthesis of mRNA. These elements may include splice signals, as well as transcription promoters, enhancers, and termination signals. cDNA expression vectors incorporating such elements include those described by Okayama (Mol. Cell. Biol. 3:280- 289, 1983). The introduced nucleic acid molecule can be incorporated into a plasmid or viral vector capable of autonomous replication in the recipient host. Any of a wide variety of vectors may be employed for this purpose. Factors of importance in selecting a particular plasmid or viral vector include: the ease with which recipient cells that contain the vector may be recognized and selected from those recipient cells which do not contain the vector; the number of copies of the vector which are desired in a particular host; and whether it is desirable to be able to "shuttle" the vector between host cells of different species.

Preferred prokaryotic vectors include plasmids such as those capable of replication in E. coli (such as, for example, pBR322, ColΕl, pSClOl, pACYC 184, πVX; "Molecular Cloning: A Laboratory Manual", 1989, supra). Bacillus plasmids include pC194, pC221, pT127, and the like (Gryczan, In: The Molecular Biology of the Bacilli, Academic Press, NY, pp. 307-329, 1982). Suitable Streptomyces plasmids include plJlOl (Kendall et al, J. Bacteriol. 169:4177-4183, 1987), and Streptomyces bacteriophages such as φC31 (Chater et al, In: Sixth International Symposium on Actinomycetales Biology, Akademiai Kaido, Budapest, Hungary, pp. 45-54, 1986). Pseudomonas plasmids are reviewed in John et al. (Rev. Infect. Dis. 8:693-704, 1986), and Izaki (Jpn. J. Bacteriol. 33:729-742, 1978).

Preferred eukaryotic plasmids include, for example, BPV, vaccinia, SV40, 2- micron circle, and the like, or their derivatives. Such plasmids are well known in the art (Botstein et al, Miami Wntr. Symp. 19:265-274, 1982; Broach, In: "The Molecular Biology of the Yeast Saccharomyces: Life Cycle and Inheritance", Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, p. 445-470, 1981; Broach, Cell 28:203-204, 1982; Bollon et al, J. Clin. Hematol. Oncol. 10:39-48, 1980; Maniatis, In: Cell Biology: A Comprehensive Treatise, Vol. 3, Gene Sequence Expression, Academic Press, NY, pp. 563-608, 1980). Once the vector or nucleic acid molecule containing the construct(s) has been prepared for expression, the DNA construct(s) may be introduced into an appropriate host cell by any of a variety of suitable means, i.e., transformation, transfection, conjugation, protoplast fusion, electroporation, particle gun technology, calcium phosphate- precipitation, direct microinjection, and the like. After the introduction of the vector, recipient cells are grown in a selective medium, which selects for the growth of vector- containing cells. Expression of the cloned gene(s) results in the production of an OMA polypeptide of the invention, or fragments thereof. This can take place in the transformed cells as such, or following the induction of these cells to differentiate (for example, by administration of bromodeoxyuracil to neuroblastoma cells or the like). A variety of incubation conditions can be used to form the peptide of the present invention. The most preferred conditions are those which mimic physiological conditions. IV. Antibodies. Hvbridomas. Methods of Use and Kits for Detection ofthe OMA Proteins

The present invention relates to an antibody having binding affinity to an OMA polypeptide ofthe invention. The polypeptide may have the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO: 5 or SEQ ID NO: 6, or a functional derivative thereof, or at least 9 contiguous amino acids thereof (preferably, at least 20, 30, 35, or 40 contiguous amino acids thereof).

The present invention also relates to an antibody having specific binding affinity to an OMA polypeptide of the invention. Such an antibody may be isolated by comparing its binding affinity to an OMA polypeptide of the invention with its binding affinity to other polypeptides. Those which bind selectively to an OMA polypeptide of the invention would be chosen for use in methods requiring a distinction between an OMA polypeptide of the invention and other polypeptides. Such methods could include, but should not be limited to, the analysis of altered OMA polypeptide expression in tissue containing other polypeptides.

The OMA polypeptides of the present invention can be used in a variety of procedures and methods, such as for the generation of antibodies, for use in identifying pharmaceutical compositions, and for studying DNA/protein interaction. The OMA polypeptides of the present invention can be used to produce antibodies or hybridomas. One skilled in the art will recognize that if an antibody is desired, such a peptide could be generated as described herein and used as an immunogen. The antibodies of the present invention include monoclonal and polyclonal antibodies, as well fragments of these antibodies, and humanized forms. Humanized forms of the antibodies of the present invention may be generated using one of the procedures known in the art such as chimerization or CDR grafting.

The present invention also relates to hybridomas that produce the above-described monoclonal antibodies, or binding fragment thereof. A hybridoma is an immortalized cell line that is capable of secreting a specific monoclonal antibody. In general, techniques for preparing monoclonal antibodies and hybridomas are well known in the art (Campbell, "Monoclonal Antibody Technology: Laboratory Techniques in Biochemistry and Molecular Biology," Elsevier Science Publishers, Amsterdam, The Netherlands, 1984; St. Groth et al, J. Immunol. Methods 35:1-21, 1980). Any animal (mouse, rabbit, and the like) which is known to produce antibodies can be immunized with the selected polypeptide. Methods for immunization are well known in the art. Such methods include subcutaneous or intraperitoneal injection of the polypeptide. One skilled in the art will recognize that the amount of polypeptide used for immunization will vary based on the animal that is immunized, the antigenicity of the polypeptide and the site of injection.

The polypeptide may be modified or administered in an adjuvant in order to increase the peptide antigenicity. Methods of increasing the antigenicity of a polypeptide are well known in the art. Such procedures include coupling the antigen with a heterologous protein (such as globulin or β-galactosidase) or through the inclusion of an adjuvant during immunization.

For monoclonal antibodies, spleen cells from the immunized animals are removed, fused with myeloma cells, such as SP2/0-Agl4 myeloma cells, and allowed to become monoclonal antibody producing hybridoma cells. Any one of a number of methods well known in the art can be used to identify the hybridoma cell that produces an antibody with the desired characteristics. These include screening the hybridomas with an ELISA assay, western blot analysis, or radioimmunoassay (Lutz et al, Exp. Cell Res. 175:109-124, 1988). Hybridomas secreting the desired antibodies are cloned and the class and subclass are determined using procedures known in the art (Campbell, "Monoclonal Antibody Technology: Laboratory Techniques in Biochemistry and Molecular Biology", supra, 1984).

For polyclonal antibodies, antibody-containing antisera is isolated from the immunized animal and is screened for the presence of antibodies with the desired specificity using one of the above-described procedures. The above-described antibodies may be detectably labeled. Antibodies can be detectably labeled through the use of radioisotopes, affinity labels (such as biotin, avidin, and the like), enzymatic labels (such as horse radish peroxidase, alkaline phosphatase, and the like) fluorescent labels (such as FITC or rhodamine, and the like), paramagnetic atoms, and the like. Procedures for accomplishing such labeling are well-known in the art, for example, see Stemberger et al, J. Histochem. Cytochem. 18:315, 1970; Bayer et al, Meth. Enzym. 62:308-, 1979; Engval et al, Immunol. 109:129-, 1972; Goding, J. Immunol. Meth. 13:215-, 1976. The labeled antibodies of the present invention can be used for in vitro, in vivo, and in situ assays to identify cells or tissues that express a specific peptide. The above-described antibodies may also be immobilized on a solid support.

Examples of such solid supports include plastics such as polycarbonate, complex carbohydrates such as agarose and sepharose, acrylic resins such as polyacrylamide and latex beads. Techniques for coupling antibodies to such solid supports are well known in the art (Weir et al, "Handbook of Experimental Immunology" 4th Ed., Blackwell Scientific Publications, Oxford, England, Chapter 10, 1986; Jacoby et al, Meth. Enzym. 34, Academic Press, N.Y., 1974). The immobilized antibodies of the present invention can be used for in vitro, in vivo, and in situ assays as well as in immunochromotography. Furthermore, one skilled in the art can readily adapt currently available procedures, as well as the techniques, methods and kits disclosed herein with regard to antibodies, to generate peptides capable of binding to a specific peptide sequence in order to generate rationally designed antipeptide peptides (Hruby et al, "Application of Synthetic Peptides: Antisense Peptides", In Synthetic Peptides, A User's Guide, W.H. Freeman, NY, pp. 289- 307, 1992; Kaspczak et al, Biochemistry 28:9230-9238, 1989).

Anti-peptide peptides can be generated by replacing the basic amino acid residues found in the peptide sequences of the OMA polypeptides of the invention with acidic residues, while maintaining hydrophobic and uncharged polar groups. For example, lysine, arginine, and/or histidine residues are replaced with aspartic acid or glutamic acid and glutamic acid residues are replaced by lysine, arginine or histidine.

The present invention also encompasses a method of detecting a OMA polypeptide in a sample, comprising: (a) contacting the sample with an above-described antibody, under conditions such that immunocomplexes form, and (b) detecting the presence of said antibody bound to the polypeptide. In detail, the methods comprise incubating a test sample with one or more of the antibodies of the present invention and assaying whether the antibody binds to the test sample. Altered levels of an OMA polypeptide of the invention in a sample as compared to normal levels may indicate disease.

Conditions for incubating an antibody with a test sample vary. Incubation conditions depend on the format employed in the assay, the detection methods employed, and the type and nature of the antibody used in the assay. One skilled in the art will recognize that any one of the commonly available immunological assay formats (such as radioimmunoassays, enzyme-linked immunosorbent assays, diffusion based Ouchterlony, or rocket immunofluorescent assays) can readily be adapted to employ the antibodies of the present invention. Examples of such assays can be found in Chard ("An Introduction to Radioimmunoassay and Related Techniques" Elsevier Science Publishers, Amsterdam, The Netherlands, 1986), Bullock et al. ("Techniques in Immunocytochemistry," Academic Press, Orlando, FL Vol. 1, 1982; Vol. 2, 1983; Vol. 3, 1985), Tijssen ("Practice and Theory of Enzyme Immunoassays: Laboratory Techniques in Biochemistry and Molecular Biology," Elsevier Science Publishers, Amsterdam, The Netherlands, 1985).

The immunological assay test samples of the present invention include cells, protein or membrane extracts of cells, or biological fluids such as blood, serum, plasma, or urine. The test samples used in the above-described method will vary based on the assay format, nature of the detection method and the tissues, cells or extracts used as the sample to be assayed. Methods for preparing protein extracts or membrane extracts of cells are well known in the art and can readily be adapted in order to obtain a sample which is testable with the system utilized. A kit contains all the necessary reagents to carry out the previously described methods of detection. The kit may comprise: (i) a first container means containing an above-described antibody, and (ii) second container means containing a conjugate comprising a binding partner of the antibody and a label. Preferably, the kit also contains instructions for use. In another preferred embodiment, the kit further comprises one or more other containers comprising one or more of the following: wash reagents and reagents capable of detecting the presence of bound antibodies.

Examples of detection reagents include, but are not limited to, labeled secondary antibodies, or in the alternative, if the primary antibody is labeled, the chromophoric, enzymatic, or antibody binding reagents that are capable of reacting with the labeled antibody. The compartmentalized kit may be as described above for nucleic acid probe kits. One skilled in the art will readily recognize that the antibodies described in the present invention can readily be incorporated into one of the established kit formats that are well known in the art.

V. Isolation of Compounds Which Interact With the OMA Polypeptides

The present invention also relates to a method of detecting a compound capable of binding to a OMA polypeptide ofthe invention, comprising incubating the compound with an OMA polypeptide of the invention and detecting the presence of the compound bound to the OMA polypeptide. The compound may be present within a complex mixture, for example, serum, body fluid, or cell extracts.

The present invention also relates to a method of detecting an agonist or antagonist of OMA polypeptide activity or OMA polypeptide binding partner activity, comprising incubating cells that produce an OMA polypeptide of the invention in the presence of a compound and detecting changes in the level of OMA polypeptide activity or OMA polypeptide binding partner activity. The compounds thus identified would produce a change in activity indicative of the presence of the compound. The compound may be present within a complex mixture, for example, serum, body fluid, or cell extracts. Once the compound is identified it can be isolated using techniques well known in the art.

The present invention also encompasses a method of agonizing (stimulating) or antagonizing OMA polypeptide associated activity in a mammal comprising administering to said mammal an agonist or antagonist to an OMA polypeptide of the invention in an amount sufficient to effect said agonism or antagonism. A method of treating diseases in a mammal with an agonist or antagonist of OMA activity comprising administering the agonist or antagonist to a mammal in an amount sufficient to agonize or antagonize OMA associated functions is also encompassed in the present application. In an effort to discover novel treatments for diseases, biomedical researchers and chemists may design, synthesize, and test molecules that inhibit the function of OMA polypeptides. Some small organic molecules may form a class of compounds that modulate the function of protein OMA polypeptides. Compounds that can traverse cell membranes and are resistant to acid hydrolysis are potentially advantageous as therapeutics as they can become highly bioavailable after being administered orally to patients. However, many of these OMA polypeptide inhibitors may only weakly inhibit the function of OMA polypeptides. In addition, many may inhibit a variety of other proteins and will therefore cause multiple side-effects as therapeutics for diseases.

VI. Transgenic Animals

A variety of methods are available for the production of transgenic animals associated with this invention. DNA can be injected into the pronucleus of a fertilized egg before fusion of the male and female pronuclei, or injected into the nucleus of an embryonic cell (e.g., the nucleus of a two-cell embryo) following the initiation of cell division (Brinster et al, Proc. Nat. Acad. Sci. USA 82: 4438-4442, 1985). Embryos can be infected with viruses, especially retroviruses, modified to carry inorganic-ion receptor nucleotide sequences ofthe invention.

Pluripotent stem cells derived from the inner cell mass of the embryo and stabilized in culture can be manipulated in culture to incorporate nucleotide sequences of the invention. A transgenic animal can be produced from such cells through implantation into a blastocyst that is implanted into a foster mother and allowed to come to term. Animals suitable for transgenic experiments can be obtained from standard commercial sources such as Charles River (Wilmington, MA), Taconic (Germantown, NY), Harlan Sprague Dawley (Indianapolis, IN), etc.

The procedures for manipulation of the rodent embryo and for microinjection of DNA into the pronucleus of the zygote are well known to those of ordinary skill in the art (Hogan et al, supra). Microinjection procedures for fish, amphibian eggs and birds are detailed in Houdebine and Chourrout (Experientia 47: 897-905, 1991). Other procedures for introduction of DNA into tissues of animals are described in U.S. Patent No., 4,945,050 (Sandford et al, July 30, 1990).

By way of example only, to prepare a transgenic mouse, female mice are induced to superovulate. Females are placed with males, and the mated females are sacrificed by CO₂ asphyxiation or cervical dislocation and embryos are recovered from excised oviducts. Surrounding cumulus cells are removed. Pronuclear embryos are then washed and stored until the time of injection. Randomly cycling adult female mice are paired with vasectomized males. Recipient females are mated at the same time as donor females. Embryos then are transferred surgically. The procedure for generating transgenic rats is similar to that of mice (Hammer et al, Cell 63:1099-1112, 1990).

Methods for the culturing of embryonic stem (ES) cells and the subsequent production of transgenic animals by the introduction of DNA into ES cells using methods such as electroporation, calcium phosphate/DNA precipitation and direct injection also are well known to those of ordinary skill in the art (Teratocarcinomas and Embryonic Stem

Cells, A Practical Approach, E.J. Robertson, ed., IRL Press, 1987).

In cases involving random gene integration, a clone containing the sequence(s) of the invention is co-transfected with a gene encoding resistance. Alternatively, the gene encoding neomycin resistance is physically linked to the sequence(s) of the invention. Transfection and isolation of desired clones are carried out by any one of several methods well known to those of ordinary skill in the art (E.J. Robertson, supra).

DNA molecules introduced into ES cells can also be integrated into the chromosome through the process of homologous recombination (Capecchi, Science 244: 1288-1292, 1989). Methods for positive selection of the recombination event (i.e., neo resistance) and dual positive-negative selection (i.e., neo resistance and gancyclovir resistance) and the subsequent identification of the desired clones by PCR have been described by Capecchi, supra and Joyner et al (Nature 338: 153-156. 1989), the teachings of which are incorporated herein in their entirety including any drawings. The final phase of the procedure is to inject targeted ES cells into blastocysts and to transfer the blastocysts into pseudopregnant females. The resulting chimeric animals are bred and the offspring are analyzed by Southern blotting to identify individuals that carry the transgene. Procedures for the production of non-rodent mammals and other animals have been discussed by others (Houdebine and Chourrout, supra; Pursel et al. Science 244:1281- 1288, 1989; and Simms et al, Bio/Technology 6:179-183, 1988).

Thus, the invention provides transgenic, nonhuman mammals containing a transgene encoding an OMA polypeptide of the invention or a gene affecting the expression of the OMA polypeptide. Such transgenic nonhuman mammals are particularly useful as an in vivo test system for studying the effects of introduction of an OMA polypeptide, or regulating the expression of an OMA polypeptide (i.e., through the introduction of additional genes, antisense nucleic acids, or ribozymes).

A "transgenic animal" is an animal having cells that contain DNA which has been artificially inserted into a cell, which DNA becomes part of the genome of the animal which develops from that cell. Preferred transgenic animals are primates, mice, rats, cows, pigs, horses, goats, sheep, dogs and cats. The transgenic DNA may encode human OMAs. Native expression in an animal may be reduced by providing an amount of anti- sense RNA or DNA effective to reduce expression ofthe receptor.

NIL Gene Therapy

OMA polypeptides or their genetic sequences will also be useful in gene therapy (reviewed in Miller, Nature 357:455-460, 1992). Miller states that advances have resulted in practical approaches to human gene therapy that have demonstrated positive initial results. The basic science of gene therapy is described in Mulligan (Science 260:926-931,

1993).

In one preferred embodiment, an expression vector containing a OMA polypeptide coding sequence is inserted into cells, the cells are grown in vitro and then infused in large numbers into patients. In another preferred embodiment, a DNA segment containing a promoter of choice (for example a strong promoter) is transferred into cells containing an endogenous gene encoding OMA polypeptides of the invention in such a manner that the promoter segment enhances expression of the endogenous OMA polypeptide gene (for example, the promoter segment is transferred to the cell such that it becomes directly linked to the endogenous OMA polypeptide gene).

The gene therapy may involve the use of an adenovirus containing OMA polypeptide cDNA targeted to a tissue, systemic OMA polypeptide increase by implantation of engineered cells, injection with OMA polypeptide-encoding virus, or injection of naked OMA polypeptide DNA into appropriate tissues.

Target cell populations may be modified by introducing altered forms of one or more components of the protein complexes in order to modulate the activity of such complexes. For example, by reducing or inhibiting a complex component activity within target cells, an abnormal signal transduction event(s) leading to a condition may be decreased, inhibited, or reversed. Deletion or missense mutants of a component, that retain the ability to interact with other components of the protein complexes but cannot function in signal transduction, may be used to inhibit an abnormal, deleterious signal transduction event.

Expression vectors derived from viruses such as retroviruses, vaccinia virus, adenovirus, adeno-associated virus, herpes viruses, several RNA viruses, or bovine papilloma virus, may be used for delivery of nucleotide sequences (e.g., cDNA) encoding recombinant OMA polypeptide of the invention protein into the targeted cell population (e.g., adipocytes). Methods which are well known to those skilled in the art can be used to construct recombinant viral vectors containing coding sequences (Maniatis et al., Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, N.Y., 1989; Ausubel et al., Current Protocols in Molecular Biology, Greene Publishing Associates and Wiley Interscience, N.Y., 1989). Alternatively, recombinant nucleic acid molecules encoding protein sequences can be used as naked DNA or in a reconstituted system e.g., liposomes or other lipid systems for delivery to target cells (e.g., Feigner et al, Nature 337:387-8, 1989). Several other methods for the direct transfer of plasmid DNA into cells exist for use in human gene therapy and involve targeting the DNA to receptors on cells by complexing the plasmid DNA to proteins (Miller, supra).

In its simplest form, gene transfer can be performed by simply injecting minute amounts of DNA into the nucleus of a cell, through a process of microinjection (Capecchi, Cell 22:479-88, 1980). Once recombinant genes are introduced into a cell, they can be recognized by the cell's normal mechanisms for transcription and translation, and a gene product will be expressed. Other methods have also been attempted for introducing DNA into larger numbers of cells. These methods include: transfection, wherein DNA is precipitated with CaPO₄ and taken into cells by pinocytosis (Chen et al, Mol. Cell Biol. 7:2745-52, 1987); electroporation, wherein cells are exposed to large voltage pulses to introduce holes into the membrane (Chu et al, Nucleic Acids Res. 15:1311-26, 1987); lipofection/liposome fusion, wherein DNA is packaged into lipophilic vesicles which fuse with a target cell (Feigner et al, Proc. Natl. Acad. Sci. USA. 84:7413-7417, 1987); and particle bombardment using DNA bound to small projectiles (Yang et al, Proc. Natl. Acad. Sci. 87:9568-9572, 1990). Another method for introducing DNA into cells is to couple the DNA to chemically modified proteins.

It has also been shown that adenovirus proteins are capable of destabilizing endosomes and enhancing the uptake of DNA into cells. The admixture of adenovirus to solutions containing DNA complexes, or the binding of DNA to polylysine covalently attached to adenovirus using protein crosslinking agents substantially improves the uptake and expression of the recombinant gene (Curiel et al, Am. J. Respir. Cell. Mol. Biol. 6:247-52, 1992).

As used herein "gene transfer" means the process of introducing a foreign nucleic acid molecule into a cell. Gene transfer is commonly performed to enable the expression of a particular product encoded by the gene. The product may include a protein, polypeptide, anti-sense DNA or RNA, or enzymatically active RNA. Gene transfer can be performed in cultured cells or by direct administration into animals. Generally gene transfer involves the process of nucleic acid contact with a target cell by non-specific or receptor mediated interactions, uptake of nucleic acid into the cell through the membrane or by endocytosis, and release of nucleic acid into the cytoplasm from the plasma membrane or endosome. Expression may require, in addition, movement of the nucleic acid into the nucleus of the cell and binding to appropriate nuclear factors for transcription. As used herein "gene therapy" is a form of gene transfer and is included within the definition of gene transfer as used herein and specifically refers to gene transfer to express a therapeutic product from a cell in vivo or in vitro. Gene transfer can be performed ex vivo on cells which are then transplanted into a patient, or can be performed by direct administration ofthe nucleic acid or nucleic acid-protein complex into the patient.

In another preferred embodiment, a vector having nucleic acid sequences encoding an OMA polypeptide is provided in which the nucleic acid sequence is expressed only in specific tissue

In all of the preceding vectors set forth above, a further aspect of the invention is that the nucleic acid sequence contained in the vector may include additions, deletions or modifications to some or all ofthe sequence ofthe nucleic acid, as defined above.

In another preferred embodiment, a method of gene replacement is set forth. "Gene replacement" as used herein means supplying a nucleic acid sequence which is capable of being expressed in vivo in an animal and thereby providing or augmenting the function of an endogenous gene that is missing or defective in the animal.

NIII. Pharmaceutical Formulations and Routes Of Administration

The compounds described herein can be administered to a human patient per se, or in pharmaceutical compositions where it is mixed with other active ingredients, as in combination therapy, or suitable carriers or excipient(s). Techniques for formulation and administration of the compounds of the instant application may be found, for example, in

"Remington's Pharmaceutical Sciences," Mack Publishing Co., Easton, PA, latest edition.

a) Routes Of Administration

Suitable routes of administration may, for example, include oral, rectal, transmucosal, or intestinal administration; parenteral delivery, including intramuscular, subcutaneous, intravenous, intrameduUary injections, as well as intrathecal, direct intraventricular, intraperitoneal, intranasal, or intraocular injections.

Alternately, one may administer the compound in a local rather than systemic manner, for example, via injection of the compound directly into a tissue of interest, often in a depot or sustained release formulation. Furthermore, one may administer the drug in a targeted drug delivery system, for example, in a liposome coated with tissue-specific antibody. The liposomes will be targeted to and taken up selectively by the tissue. b) Composition/Formulation

The pharmaceutical compositions of the present invention may be manufactured in a manner that is itself known, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes.

Pharmaceutical compositions for use in accordance with the present invention thus may be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries that facilitate processing of the active compounds into preparations that can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen.

For injection, the agents of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks's solution. Ringer's solution, or physiological saline buffer. For transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.

For oral administration, the compounds can be formulated readily by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient to be treated. Suitable carriers include excipients such as, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP). If desired, disintegrating agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate.

Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.

Pharmaceutical preparations that can be administered orally, include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers may be added. All formulations for oral administration should be in dosages suitable for such administration. For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.

For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebuliser, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of e.g. gelatin for use in an inhaler or insufflator may be formulated containing a powder mix ofthe compound and a suitable powder base such as lactose or starch.

The compounds may be formulated for parenteral administration by injection, e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Pharmaceutical formulations for parenteral administration include aqueous solutions ofthe active compounds in water-soluble form. Additionally, suspensions of the active compounds may be prepared as appropriate oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or liposomes. Aqueous injection suspensions may contain substances that increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, the suspension may also contain suitable stabilizers or agents that increase the solubility of the compounds to allow for the preparation of highly concentrated solutions.

Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.

The compounds may also be formulated in rectal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides.

In addition to the formulations described previously, the compounds may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the compounds may be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.

A pharmaceutical carrier for the hydrophobic compounds of the invention is a cosolvent system comprising benzyl alcohol, a nonpolar surfactant, a water-miscible organic polymer, and an aqueous phase. The cosolvent system may be the VPD co- solvent system. VPD is a solution of 3% w/v benzyl alcohol, 8% w/v of the nonpolar surfactant polysorbate 80, and 65% w/v polyethylene glycol 300, made up to volume in absolute ethanol. The VPD co-solvent system (VPD:D5W) consists of VPD diluted 1:1 with a 5% dextrose in water solution. This co-solvent system dissolves hydrophobic compounds well, and itself produces low toxicity upon systemic administration. Naturally, the proportions of a co-solvent system may be varied considerably without destroying its solubility and toxicity characteristics. Furthermore, the identity of the co- solvent components may be varied: for example, other low-toxicity nonpolar surfactants may be used instead of polysorbate 80; the fraction size of polyethylene glycol may be varied; other biocompatible polymers may replace polyethylene glycol, e.g. polyvinyl pyrrolidone; and other sugars or polysaccharides may substitute for dextrose.

Alternatively, other delivery systems for hydrophobic pharmaceutical compounds may be employed. Liposomes and emulsions are well known examples of delivery vehicles or carriers for hydrophobic drugs. Certain organic solvents such as dimethylsulfoxide also may be employed, although usually at the cost of greater toxicity. Additionally, the compounds may be delivered using a sustained-release system, such as semipermeable matrices of solid hydrophobic polymers containing the therapeutic agent. Various sustained-release materials have been established and are well known by those skilled in the art. Sustained-release capsules may, depending on their chemical nature, release the compounds for a few weeks up to over 100 days. Depending on the chemical nature and the biological stability of the therapeutic reagent, additional strategies for protein stabilization may be employed.

The pharmaceutical compositions also may comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include but are not limited to calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols.

Many of the compounds of the invention may be provided as salts with pharmaceutically compatible counterions. Pharmaceutically compatible salts may be formed with many acids, including but not limited to hydrochloric, sulfuric, acetic, lactic, tartaric, malic, succinic, etc. Salts tend to be more soluble in aqueous or other protonic solvents that are the corresponding free base forms. c Effective Dosage

Pharmaceutical compositions suitable for use in the present invention include compositions where the active ingredients are contained in an amount effective to achieve its intended purpose. More specifically, a therapeutically effective amount means an amount of compound effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated. Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light ofthe detailed disclosure provided herein.

For any compound used in the methods of the invention, the therapeutically effective dose can be estimated initially from cell culture assays. For example, a dose can be formulated in animal models to achieve a circulating concentration range that includes the IC₅₀ as determined in cell culture (i.e., the concentration of the test compound that achieves a half-maximal inhibition of the PTK activity). Such information can be used to more accurately determine useful doses in humans. Toxicity and therapeutic efficacy of the compounds described herein 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 ED₅o (the dose therapeutically effective in 50% ofthe population). The dose ratio between toxic and therapeutic effects is the therapeutic index and it can be expressed as the ratio between LD₅₀ and ED₅₀. Compounds that exhibit high therapeutic indices are preferred. The data obtained from these cell culture assays and animal studies can be used in formulating a range of dosage for use in human. The dosage of such compounds lies preferably within a range of circulating concentrations that include the ED₅_ with little or no toxicity. The dosage may vary within this range depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration, and dosage can be chosen by the physician in view of the patient's condition. (See e.g., Fingl et al, 1975, in "The Pharmacological Basis of Therapeutics", Ch. 1 p.l).

Dosage amount and interval may be adjusted individually to provide plasma levels of the active moiety which are sufficient to maintain the OMA polypeptide modulating effects, or minimal effective concentration (MEC). The MEC will vary for each compound but can be estimated from in vitro data; e.g., the concentration necessary to achieve 50-90% inhibition of the OMA polypeptide using the assays described herein. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. However, HPLC assays or bioassays can be used to determine plasma concentrations. Dosage intervals can also be determined using MEC value. Compounds should be administered using a regimen that maintains plasma levels above the MEC for 10-90% of the time, preferably between 30-90% and most preferably between 50-90%.

In cases of local administration or selective uptake, the effective local concentration ofthe drug may not be related to plasma concentration.

The amount of composition administered will, of course, be dependent on the subject being treated, on the subject's weight, the severity of the affliction, the manner of administration and the judgment ofthe prescribing physician.

d Packaging The compositions may, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing the active ingredient. The pack may for example comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accompanied with a notice associated with the container in form prescribed by a governmental agency regulating the manufacture, use, or sale of pharmaceuticals, which notice is reflective of approval by the agency of the form of the polynucleotide for human or veterinary administration. Such notice, for example, may be the labeling approved by the U.S. Food and Drug Administration for prescription drugs, or the approved product insert. Compositions comprising a compound of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition. Suitable conditions indicated on the label may include treatment of a tumor, inhibition of angiogenesis, treatment of fibrosis, diabetes, and the like.

IX. Functional Derivatives and Chemical Derivatives Also provided herein are functional derivatives of nucleic acids of the invention.

By "functional derivative" is meant a "chemical derivative," "fragment," or "variant," of the nucleic acids of the invention, which terms are defined below. It is well known in the art that due to the degeneracy of the genetic code numerous different nucleic acid sequences can code for the same amino acid sequence. All such permutations are intended to be covered by this disclosure.

Included within the scope of this invention are the functional equivalents of the herein-described isolated nucleic acid molecules. The degeneracy of the genetic code permits substitution of certain codons by other codons that specify the same amino acid and hence would give rise to the same protein. The nucleic acid sequence can vary substantially since, with the exception of methionine and tryptophan, the known amino acids can be coded for by more than one codon. Thus, portions or all of the OMA polypeptide genes could be synthesized to give a nucleic acid sequence significantly different from that shown in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4. The encoded amino acid sequence thereof would, however, be preserved. In addition, the nucleic acid sequence may comprise a nucleotide sequence which results from the addition, deletion or substitution of at least one nucleotide to the 5'-end and/or the 3'-end of the nucleic acid formula shown in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4, or a derivative thereof. Any nucleotide or polynucleotide may be used in this regard, provided that its addition, deletion or substitution does not alter the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6 which is encoded by the nucleotide sequence. For example, the present invention is intended to include any nucleic acid sequence resulting from the addition of ATG as an initiation codon at the 5'-end of the inventive nucleic acid sequence or its derivative, or from the addition of TAA, TAG or TGA as a termination codon at the 3'-end of the inventive nucleotide sequence or its derivative. Moreover, the nucleic acid molecule of the present invention may, as necessary, have restriction endonuclease recognition sites added to its 5'-end and/or 3'-end.

Such functional alterations of a given nucleic acid sequence afford an opportunity to promote secretion and/or processing of heterologous proteins encoded by foreign nucleic acid sequences fused thereto. All variations of the nucleotide sequence of the OMA polypeptide genes of the invention and fragments thereof permitted by the genetic code are, therefore, included in this invention.

Further, it is possible to delete codons or to substitute one or more codons with codons other than degenerate codons to produce a structurally modified polypeptide, but one which has substantially the same utility or activity as the polypeptide produced by the unmodified nucleic acid molecule. As recognized in the art, the two polypeptides are functionally equivalent, as are the two nucleic acid molecules that give rise to their production, even though the differences between the nucleic acid molecules are not related to the degeneracy ofthe genetic code.

A "chemical derivative" of a polypeptide contains additional chemical moieties not normally a part of the polypeptide. Covalent modifications of the OMA polypeptides are included within the scope of this invention. Such modifications may be introduced into the molecule by reacting targeted amino acid residues of the peptide with an organic derivatizing agent that is capable of reacting with selected side chains or terminal residues, as described below. Cysteinyl residues most commonly are reacted with alpha-haloacetates (and corresponding amines), such as chloroacetic acid or chloroacetamide, to give carboxy- methyl or carboxyamidomethyl derivatives. Cysteinyl residues also are derivatized by reaction with bromotrifluoroacetone, chloroacetyl phosphate, N-alkylmaleimides, 3-nitro- 2-pyridyl disulfide, methyl 2-pyridyl disulfide, p-chloromercuribenzoate, 2-chloromercuri- 4-nitrophenol, or chloro-7-nitrobenzo-2-oxa-l,3-diazole.

Histidyl residues are derivatized by reaction with diethylprocarbonate at pH 5.5- 7.0 because this agent is relatively specific for the histidyl side chain. Para- bromophenacyl bromide also is useful; the reaction is preferably performed in 0.1 M sodium cacodylate at pH 6.0.

Lysinyl and amino terminal residues are reacted with succinic or other carboxylic acid anhydrides. Derivatization with these agents has the effect or reversing the charge of the lysinyl residues. Other suitable reagents for derivatizing primary amine containing residues include imidoesters such as methyl picolinimidate; pyridoxal phosphate; pyridoxal; chloroborohydride; trinitrobenzenesulfonic acid; O-methylisourea; 2,4 pentanedione; and transaminase-catalyzed reaction with glyoxylate.

Arginyl residues are modified by reaction with one or several conventional reagents, among them phenylglyoxal, 2,3-butanedione, 1,2-cyclohexanedione, and ninhydrin. Derivatization of arginine residues requires that the reaction be performed in alkaline conditions because of the high pK_a of the guanidine functional group. Furthermore, these reagents may react with the groups of lysine as well as the arginine alpha- amino group.

Tyrosyl residues are well-known targets of modification for introduction of spectral labels by reaction with aromatic diazonium compounds or tetranitromethane. Most commonly, N-acetylimidizol and tetranitromethane are used to form O-acetyl tyrosyl species and 3-nitro derivatives, respectively.

Carboxyl side groups (aspartyl or glutamyl) are selectively modified by reaction with carbodiimide (R'-N-C-N-R') such as l-cyclohexyl-3-(2-morpholinyl(4-ethyl) carbodiimide or l-ethyl-3-(4-azonia-4,4-dimethylpentyl) carbodiimide. Furthermore. aspartyl and glutamyl residues are converted to asparaginyl and glutaminyl residues by reaction with ammonium ions.

Glutaminyl and asparaginyl residues are frequently deamidated to the corresponding glutamyl and aspartyl residues. Alternatively, these residues are deamidated under mildly acidic conditions. Either form of these residues falls within the scope of this invention.

Derivatization with bifunctional agents is useful, for example, for cross-linking the component peptides of the protein to each other or to other proteins in a complex to a water-insoluble support matrix or to other macromolecular carriers. Commonly used cross-linking agents include, for example, l,l-bis(diazoacetyl)-2-phenylethane, glutaraldehyde, N-hydroxysuccinimide esters, for example, esters with 4-azidosalicylic acid, homobifunctional imidoesters, including disuccinimidyl esters such as 3,3'- dithiobis(succinimidylpropionate), and bifunctional maleimides such as bis-N-maleimido- 1,8-octane. Derivatizing agents such as methyl-3-[p-azidophenyl) dithiolpropioimidate yield photo activatable intermediates that are capable of forming crosslinks in the presence of light. Alternatively, reactive water-insoluble matrices such as cyanogen bromide- activated carbohydrates and the reactive substrates described in U.S. Patent Nos. 3,969,287; 3,691,016; 4,195,128; 4,247,642; 4,229,537; and 4,330,440 are employed for protein immobilization.

Other modifications include hydroxylation of proline and lysine, phosphorylation of hydroxyl groups of seryl or threonyl residues, methylation of the alpha-amino groups of lysine, arginine, and histidine side chains (Creighton, T.E., Proteins: Structure and Molecular Properties, W.H. Freeman & Co., San Francisco, pp. 79-86 (1983)), acetylation of the N-terminal amine, and, in some instances, amidation of the C-terminal carboxyl groups.

Such derivatized moieties may improve the stability, solubility, absorption, biological half life, and the like. The moieties may alternatively eliminate or attenuate any undesirable side effect of the protein complex and the like. Moieties capable of mediating such effects are disclosed, for example, in Remington's Pharmaceutical Sciences, 18th ed., Mack Publishing Co., Easton, PA (1990).

EXAMPLES

The examples below are not limiting and are merely representative of various aspects and features of the present invention. The examples below demonstrate the isolation and characterization ofthe OMA polypeptides ofthe invention.

EXAMPLE 1 : ANIMAL MODELS/RNA PREPARATION

Retroperitoneal fat, brain, liver, muscle, and pancreas were harvested from six mice (male, 12 to 14 weeks of age) from each of the following test groups: Hsd:NIHS (Swiss); Aurothioglucose (Gold thioglucose or GTG) treated obese Hsd:NIHS (GTG Swiss); C57BL/6J-m+/+ Lepr^db (db/db); and C57BL/6J- Lepr^oώ (ob/ob) mice. The GTG treated Swiss mice were obtained by administering Aurothioglucose (350 ug/g, Sigma A0632) to 8 week old Hsd:NIHS mice via a single intraperitoneal dose. All harvested tissues were immediately frozen in liquid nitrogen and subsequently stored at -70°C. The pooled tissues from each group were pulverized using a mortar and pestle continuously chilled in liquid nitrogen. Approximately 2 grams of pulverized tissue was used for RNA extraction using TRI REAGENT^® (Molecular Research Center, Inc., Cincinnati, OH) following the manufacturer's protocol. The RNA was solubilized in DEPC (diethyl pyrocarbonate)-treated, nuclease-free H₂O (Ambion, Inc., Austin, TX). The RNA was quantitated using standard spectrophotometric techniques (Current Protocols in Molecular Biology, J. Wiley & Sons, Inc.) and analyzed for integrity by electrophoresing an aliquot on a 1% TBE-agarose gel. The RNA samples were stored at - 70°C.

EXAMPLE 2: DIFFERENTIAL DISPLAY

The Delta RNA Fingerprinting Kit (Clontech, Inc., Palo Alto, CA, protocol #PT1173-1, version #PR58480) was employed to produce PCR profiles of the RNA expressed in each mouse model's retroperitoneal fat tissue, following the manufacturer's protocol. The Advantage™ KlenTaq Polymerase Mix (Clontech Inc., Palo Alto, CA) was used to generate the PCR fragments along with the "P" primers (Pl through P10), either alone or in pairwise combinations. The differential display PCR fragments were electrophoresed on an 8% TBE denaturing acrylamide gel, using 0.4 mm thick spacers. The gels were transferred to blotting paper, dried and exposed to BIOMAX™ MR film (Kodak) overnight. Differentially expressed fragments were identified, cut out of the gels, eluted and reamplified according to the manufacturer's protocol using the same "P" primers employed in the initial amplification. The reamplified fragments were then subcloned into the pCR™II vector (Invitrogen, Inc., San Diego, CA) using the TA Cloning® Kit (Invitrogen, Inc., San Diego, CA) following the manufacturer's protocol.

EXAMPLE 3: SEQUENCING DNA was extracted using the Wizard™ Minipreps DNA Purification System

(Promega, Corp., Madison, WI) following the manufacturer's protocol. Sequencing was accomplished using the dsDNA Cycle Sequencing System (GibcoBRL, Gaithersburg, MD) following the manufacturer's protocol. The sequence reactions were separated on an 8% TBE denaturing polyacrylamide gel and exposed to BIOMAX™ MR (Kodak) film using standard techniques (Current Protocols in Molecular Biology; Ausubel, F. M., et al; John Wiley and Sons Inc.; 1998). Alternatively, DNA was prepared using the ABI Prism™ Miniprep Kit (PE Applied Biosystems, Foster City, CA) and sequenced using the ABI Prism™ dRhodamine Terminator Cycle Sequencing Ready Reaction Kit (PE Applied Biosystems, Foster City, CA) following the manufacturer's protocol. Sequence reactions were thermocycled on the GeneAmp® PCR System 9700 and were run on the ABI Prism® 377 automated sequencer (PE Applied Biosystems, Foster City, CA) following the manufacturer's protocol. The sequence information was compiled using the sequence analysis programs contained in the DNAStar (DNAStar, Inc., Madison, WI) software package. The sequences for each fragment, confirmed by Northern Blot hybridization as differentially expressed, were analyzed using the NCBI (National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD) BLAST (Altschul, S. F., et al, Nucleic Acids Res. 25:3389-3402, 1997; Karlin, S., et al, PNAS USA 87:2264-68, 1990; Karlin, S., et al, PNAS USA 90:5873-7, 1993) programs to determine if the fragment represented a novel or previously reported sequence. Various protein prediction databases were employed in analyzing nucleotide sequences including the TMPred (Prediction of Transmembrane Regions and Orientation, K. Hofrnan and W. Stoffel, Biol. Chem., Hoppe-Seyler 347:166, 1993) program from ISREC Bioinformatics Group (Swiss Institute for Experimental Cancer Research) and the SignalP (Nielse, H., et al, Protein Engineering, 10:1-6, 1997) program from the EXPASY database (University of Geneva, Geneva, Switzerland).

EXAMPLE 4: NORTHERN BLOT ANALYSIS

Northern Blots were prepared using 20ug of total RNA from the retroperitoneal fat of the Swiss, GTG-treated Swiss, db/db, and ob/ob mice in order to confirm differential expression. RNA was size fractionated on 2.0% denaturing formaldehyde agarose gels and transferred to Nytran® Plus (0.2um) membranes by capillary blotting in 10X SSC (IX SSC = 0.15 M NaCI, 0.015 M Na₃citrate-2H₂O, pH 7.0) buffer following standard protocols (Current Protocols in Molecular Biology; Ausubel, F. M., et al; John Wiley and Sons Inc.; 1998). Following transfer, the RNA was cross-linked to the membrane by UV- light exposure using the Stratalinker® UN Crosslinker (Stratagene, La Jolla, CA) or by baking the membranes, under vacuum, at 80°C for one to two hours. In some cases, a

Northern Blot was completed with an expanded number of tissues from all four mouse models. These Northern Blots were prepared as outlined but included 20ug of total RNA from the following tissues: brain, liver, muscle, and pancreas as well as retroperitoneal fat.

Radioactive DNA probes were prepared from the differential display fragments using two methods. An aliquot of the reamplified fragment was random prime labeled with α-³²P-dCTP (Amersham Corp., Arlington Heights, IL, catalog #PB 10205) using the Redi-Prime Kit™ (Amersham Corp., Arlington Heights, IL) or the Prime-It™ II Kit (Stratagene, Inc., San Diego CA) following the manufacturer's protocol. The labeled material was further purified using the Ultrafree®-MC spin column (Millipore, catalog #UFC3LTKNB) following the manufacturer's protocol. Alternatively, a PCR labeling technique (Schowalter, D.B. and Sommer, S.S. 1989. The generation of radiolabeled DNA and RNA probes with polymerase chain reaction. Anal. Biochem. 177:90-94.) was utilized. The differential display fragment, either subcloned into the pCRII™ vector or a purified fragment, was used as a template in PCR amplification using the "P" primers (originally incorporated into the fragment in the initial RNA fingerprinting). α-³²P-dCTP (Amersham Corp., Arlington Heights, IL, catalog #PB 10205) was used in the PCR reaction replacing the cold dCTP. As with the random primed probes, the PCR probes were subsequently purified using the Ultrafree®-MC columns.

Hybridizations were completed using ExpressHyb™ Hybridization Solution (Clontech, Palo Alto, CA) following the manufacturer's protocol for Northern Blot Hybridization with cDNA probes. The denatured probes were added to a final concentration of 1 to 2 million dpm/ml of hybridization solution. Washes were performed per manufacturer's recommendation and additionally with Wash Buffer II (0.1X SSC/0.1%SDS) at > 65°C as necessary. Washed blots were exposed to XAR film (Kodak) at -70°C with intensifying screens.

EXAMPLE 5: CDNA CLONING

Two techniques were employed to obtain a longer or full-length cDNAs: GeneTrapper™ cDNA Positive Selection System (GIBCO/Life Technologies, Gaithersburg, MD) and 5' RACE System (GIBCO/Life Technologies, Gaithersburg, MD). An ob/ob mouse retroperitoneal fat cDNA library was constructed (Invitrogen Inc, San Diego, CA) for the GeneTrapper™ methodology. The mRNA was oligo dT primed for first strand cDNA synthesis, size selected (>800bp), cloned directionally into pcDNA3.1+ (Invitrogen Inc.) and transformed into TOPI OF' cells (Invitrogen Inc.). The number of primary recombinants in the library was 1.6 x 10⁶ with the average insert size of 1.46 kbp. The capture and repair oligos required for GeneTrapper™ were designed from the sequence information obtained from the differential display fragments. For P4P6B1, the same oligonucleotide was employed for both the capture and repair reactions (5'- TCCATCCTGTCGGCGAGTTCTAT-3') (SEQ ID NO:l 1). For P7P7C1, the capture oligo (5'- CAAGACAGTAGCCCTGGCTGTCC-3') (SEQ ID NO:12) was also used for the repair reaction as was the case for P6P7A (capture oligo = 5'- TGGTTGTAGACCTCTGATCCATG-3') (SEQ ID NO: 13). In cases where GeneTrapper™ was not successful in producing a longer or full-length cDNA clone, the 5' RACE System (GIBCO/Life Technologies, Gaithersburg, MD) was employed. Oligos were designed from the sequence information obtained from either the GeneTrapper™ cDNA clones or the differential display fragments and 5' RACE performed as per the manufacturer's protocol. In the case of P4P6B1, the oligonucleotides used for the primary and nested PCR reactions were 5'-GACAGGATGGACGAGTCAGCTG-3' (SEQ ID NO: 14) and 5'-CAUCAUCAUCAUGAGATGTACACAGGGCAGAGG-3'(SEQ ID NO: 15), respectively. 5' RACE products were subcloned into the pCR^®2.1 vector (Invitrogen, Inc., San Diego, CA) for characterization.

One skilled in the art would readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The molecular complexes and the methods, procedures, treatments, molecules, specific compounds described herein are presently representative of preferred embodiments are exemplary and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit ofthe invention are defined by the scope ofthe claims.

It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit ofthe invention.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

Other embodiments are within the following claims.

Claims

Claims

1. An isolated, enriched or purified nucleic acid molecule encoding an OMA polypeptide, or a fragment thereof.

2. The nucleic acid molecule of claim 1, wherein said nucleic acid molecule comprises a nucleotide sequence that:

(a) encodes a polypeptide having the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6;

(b) is the complement ofthe nucleotide sequence of (a); (c) hybridizes under stringent conditions to the nucleotide molecule of (a) and encodes a naturally occurring polypeptide selected from the group consisting of P4P6B1, P7P7C1, P10P10C5, and P6P7A;

(d) encodes a polypeptide having the amino acid sequence of SEQ ID NO:5 or SEQ ID NO:6, except that it lacks one or more, but not all, of the following segments of amino acid residues: 7-27, 49-68, 84-103, 139-157, 163-182, 184-207, 237-259, 272-294, 326-348, 377-399, 403-430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119-137, 138-160, 161-325, 326-354, 355-370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6;

(e) is the complement ofthe nucleotide sequence of (d); (f) encodes a polypeptide having the amino acid sequence set forth in SEQ ID

NO:5 or SEQ ID NO:6 from amino acid residues 7-27, 49-68, 84-103, 139-157, 163-182, 184-207, 237-259, 272-294, 326-348, 377-399, 403-430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119-137, 138-160, 161-325, 326-354, 355-370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6; (g) is the complement ofthe nucleotide sequence of (f);

(h) encodes a polypeptide having the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6, except that it lacks one or more, but not all, of the domains selected from the group consisting of an extracellular domain, a transmembrane domain, and an intracellular domain; or (i) is the complement of the nucleotide sequence of (h).

3. The nucleic acid molecule of claim 1, further comprising a vector or promoter effective to initiate transcription in a host cell.

4. The nucleic acid molecule of claim 1, wherein said nucleic acid molecule is isolated, enriched, or purified from a mammal.

5. The nucleic acid molecule of claim 4, wherein said mammal a mouse.

5. The nucleic acid molecule of claim 4, wherein said mammal is a human.

6. A nucleic acid probe for the detection of nucleic acid encoding an OMA polypeptide in a sample.

7. The probe of claim 6, wherein said polypeptide is a fragment of the protein encoded by the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6.

8. A recombinant cell comprising a nucleic acid molecule encoding an OMA polypeptide.

9. The cell of claim 8, wherein said polypeptide is a fragment of the protein encoded by the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6.

10. An isolated, enriched, or purified OMA polypeptide.

11. The polypeptide of claim 10, wherein said polypeptide is a fragment of the protein encoded by the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6.

12. The polypeptide of claim 10, wherein said polypeptide comprises an amino acid sequence having

(a) the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6; (b) the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6, except that it lacks one or more, but not all, ofthe following segments of amino acid residues: 7- 27, 49-68, 84-103, 139-157, 163-182, 184-207, 237-259, 272-294, 326-348, 377-399, 403- 430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119-137, 138-160, 161-325, 326-354, 355-370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6;

(c) the amino acid sequence set forth in SEQ ID NO: 5 or SEQ ID NO:6from amino acid residues 7-27, 49-68, 84-103, 139-157, 163-182, 184-207, 237-259, 272-294, 326-348, 377-399, 403-430, 429-456, or 481-502 of SEQ ID NO:5 or 1-21, 22-50, 51-57, 58-83, 84-96, 97-118, 119-137, 138-160, 161-325, 326-354, 355-370, 371-396, 397-409, 410-431, or 432-477 of SEQ ID NO:6; or

(d) the amino acid sequence set forth in SEQ ID NO: 5 or SEQ ID NO: 6, except that it lacks one or more, but not all, of the domains selected from the group consisting of an extracellular domain, a transmembrane domain, and an intracellular domain.

13. The polypeptide of claim 10, wherein said polypeptide is isolated, purified, or enriched from a mammal.

14. The polypeptide of claim 13, wherein said mammal is a mouse.

15. The polypeptide of claim 13, wherein said mammal is a human.

16. The polypeptide of claim 10, wherein said polypeptide is isolated, purified, or enriched from a cell that comprises an endogenous nucleic acid molecule that encodes said polypeptide.

17. The polypeptide of claim 10, wherein said polypeptide is isolated, purified, or enriched from a cell that is transformed with a nucleic acid molecule that encodes said polypeptide.

18. The polypeptide of claim 10, wherein said polypeptide is chemically synthesized.

19. An antibody or antibody fragment having specific binding affinity to an OMA polypeptide or to a domain of said OMA polypeptide.

20. A hybridoma which produces an antibody having specific binding affinity to an OMA polypeptide.

21. A method for identifying a substance that modulates the activity of an OMA polypeptide, said method comprising: (a) contacting said polypeptide with a test substance;

(b) measuring the activity of said polypeptide; and

(c) determining whether said substance modulates the activity of said polypeptide.

22. A method for identifying a substance that modulates the activity of an

OMA polypeptide in a cell, said method comprising:

(a) expressing said polypeptide in a cell;

(b) contacting said cell with a test substance; and

(c) monitoring a change in cell phenotype or the interaction between said polypeptide and a natural binding partner to identify said substance that modulates said polypeptide activity in said cell.

23. A method of diagnosing a disorder of fuel metabolism in an individual, comprising detection of a gene transcript level, wherein said gene encodes an OMA polypeptide, and wherein said level is induced or repressed in said individual by a factor selected from the group consisting of genetic obesity, fasting, and refeeding of a fasted individual, and wherein said individual is selected from the group consisting of an underweight individual and an overweight individual.

24. A method of treating a patient having a disorder of fuel metabolism which may be treated by a substance that modulates one or more activities of an OMA polypeptide in vitro comprising the step of administering to said patient a therapeutically effective amount of said compound.

25. The method of claim 24, wherein said disorder of fuel metabolism is selected from the group consisting of obesity and diabetes.

26. The method of claim 24, wherein said substance is an inhibitor of said polypeptide.

27. The method of claim 26, wherein said substance is an antisense oligonucleotide that inhibits the expression of said polypeptide.

28. A method for detection of a nucleic acid encoding an OMA polypeptide in a sample as a diagnostic tool for a disorder of fuel metabolism, wherein said method comprises: (a) contacting said sample with a nucleic acid probe which hybridizes under hybridization assay conditions to a nucleic acid target region of said polypeptide, said probe comprising the nucleic acid sequence encoding said polypeptide, fragments thereof, and the complements of said sequences and fragments; and (b) detecting the presence or amount of the probe:target region hybrid as an indication of said disorder of fuel metabolism.

29. The method of claim 28, wherein said disorder of fuel metabolism is selected from the group consisting of obesity and diabetes.

30. An antisense oligonucleotide that inhibits the expression of an OMA polypeptide.

31. The antisense oligonucleotide of claim 30, wherein said oligonucleotide is the complement of a sequence encoding a fragment of a protein encoded by the amino acid sequence encoded by the nucleic acid sequence set forth in SEQ ID NO:l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, or the amino acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6.