WO2001029263A1 - Drug target isogenes: polymorphisms in the 5-hydroxytryptamine (serotonin) receptor 1e gene - Google Patents

Drug target isogenes: polymorphisms in the 5-hydroxytryptamine (serotonin) receptor 1e gene Download PDF

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WO2001029263A1
WO2001029263A1 PCT/US2000/028584 US0028584W WO0129263A1 WO 2001029263 A1 WO2001029263 A1 WO 2001029263A1 US 0028584 W US0028584 W US 0028584W WO 0129263 A1 WO0129263 A1 WO 0129263A1
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htrie
gene
haplotype
individual
nucleotide
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PCT/US2000/028584
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French (fr)
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Julie Y. Choi
R. Rex Denton
Krishnan Nandabalan
J. Claiborne Stephens
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Genaissance Pharmaceuticals, Inc.
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Priority to AU15707/01A priority Critical patent/AU1570701A/en
Publication of WO2001029263A1 publication Critical patent/WO2001029263A1/en

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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07KPEPTIDES
    • C07K14/00Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • C07K14/705Receptors; Cell surface antigens; Cell surface determinants
    • C07K14/70571Receptors; Cell surface antigens; Cell surface determinants for neuromediators, e.g. serotonin receptor, dopamine receptor
    • CCHEMISTRY; METALLURGY
    • C12BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12QMEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
    • C12Q1/00Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/68Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving nucleic acids
    • C12Q1/6876Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes
    • C12Q1/6883Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes for diseases caused by alterations of genetic material
    • CCHEMISTRY; METALLURGY
    • C12BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12QMEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
    • C12Q2600/00Oligonucleotides characterized by their use
    • C12Q2600/156Polymorphic or mutational markers

Definitions

  • This invention relates to variation in genes that encode pharmaceutically important proteins.
  • this invention provides genetic variants of the human 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) gene and methods for identifying which variant(s) of this gene is/are possessed by an individual.
  • HTRIE 5-hydroxytryptamine receptor IE
  • a target protein currently used to screen drugs typically is expressed by a gene cloned from an individual who was arbitrarily selected.
  • the nucleotide sequence of a particular gene may vary tremendously among individuals.
  • Subtle alteration(s) in the primary nucleotide sequence of a gene encoding a target protein may be manifested as significant variation in expression of or in the structure and/or function of the protein. Such alterations may explain the relatively high degree of uncertainty inherent in treatment of individuals with drugs whose design is based upon a single representative example of the target.
  • haplotype The organization of single nucleotide variations (polymorphisms) in the primary sequence of a gene into one of the limited number of combinations that exist as units of inheritance is termed a haplotype. Each haplotype therefore contains significantly more information than individual unorganized polymorphisms. Haplotypes provide an accurate measurement of the genomic variation in the two chromosomes of an individual and can be used to identify and distinguish between isoforms of genes coding for drug targets.
  • the marker may be predictive in some populations, but not in other populations (Clark AG et al. 1998 supra). In these instances, a haplotype will provide a superior genetic marker for the phenotype (Clark AG et al. 1998 supra; Ulbrecht M et al. 2000, supra; Rua ⁇ o G & Stephens JC Gen EngNews 19 (21), December 1999).
  • HTRIE 5- hydroxytryptamine receptor IE
  • 5-HT-1E receptor is a G-protein-coupled receptor and is one of several 5-HT-l receptor subtypes for serotonin (5-hydroxytryptamine or 5-HT), a key neurotransmitter implicated in various cognitive and behavioral functions including, mood, sleep, appetite, depression and learning (for review, see Pauwels, P J., Gen. Pharmacol. 29:293-303, 1997; Hasler, W.L., Dig. Dis. Sci. 44: 108S- 113S, 1999).
  • HTRIE is expressed in the brain, at higher levels in the caudate (72%) and putamen (64%), and in lower levels in the hippocampus (16%) (Lowther et al., Eur. J. Pharmacol. 1992 Nov 3;222(1): 137-42).
  • Pranzatelli et al Exp Neurol 1992 Mar;l 15(3):423-7 have suggested that HTRIE may have clinical implications as a tumor marker. They studied the various types of seratonin receptors in thirteen neuroblastomas from children and reported that among other serotonin receptors, only HTRIE and HT-3 receptors were detected in neuroblastomas.
  • the 5-hydroxytryptamine (serotonin) receptor IE gene is located on chromosome 6ql4-ql5 and contains 1 exon that encodes a 365 amino acid protein.
  • Reference sequences for the HTRIE gene (GenBank Accession No:Zl 1166.1 ; SEQ ID NO: 1), coding sequence, and protein are shown in Figures 1, 2 and 3, respectively.
  • Figure 1 has been reported in the NCBI SNP Database (Ref SNP#6302) released on July 15, 1999. Because of the potential for polymorphisms in the HTRIE gene to affect the expression and function of the encoded protein, it would be useful to determine whether additional polymorphisms exist in the HTRIE gene, as well as how such polymorphisms are combined in different copies of the gene. Such information would be useful for studying the biological function of HTRIE as well as in identifying drugs targeting this protein for the treatment of disorders related to its abnormal expression or function.
  • This polymo ⁇ hic site corresponds to nucleotide position 737 in GenBank Accession Number Z 11166.1 , and is operationally designated herein as PS 1.
  • the polymo ⁇ hism at PS 1 is cytosine or thymine.
  • the inventors have determined the identity of the alternative nucleotide present at this site, as well as at the previously identified site at nucleotide 878 (PS2), in a human reference population of 79 unrelated individuals self-identified as belonging to one of four major population groups: African descent, Asian, Caucasian and Hispanic/Latino.
  • HTR IE-encoding polynucleotides containing the novel polymo ⁇ hic site reported herein will be useful in studying the expression and biological function of HTRIE, as well as in developing drugs targeting this protein.
  • information on the combinations of polymo ⁇ hisms in the HTRIE gene may have diagnostic and forensic applications.
  • the invention provides an isolated polynucleotide comprising a nucleotide sequence which is a polymo ⁇ hic variant of a reference sequence for the HTRIE gene or a fragment thereof.
  • the reference sequence comprises SEQ ID NO: 1 and the polymo ⁇ hic variant comprises thymine at PS 1.
  • the polymo ⁇ hic variant comprises an additional polymo ⁇ hism of thymine at PS2.
  • a particularly preferred polymo ⁇ hic variant is a naturally-occurring isoform (also referred to herein as an "isogene") of the HTRIE gene.
  • a HTRIE isogene of the invention comprises cytosine or thymine at PS1 and cytosine or thymine at PS2.
  • the invention also provides a collection of HTRIE isogenes, referred to herein as a HTRIE genome anthology.
  • a HTRIE isogene may be defined by the combination and order of these polymo ⁇ hisms in the isogene, which is referred to herein as a HTRIE haplotype.
  • the invention also provides data on the number of different HTRIE haplotypes found in the above four population groups. This haplotype data is useful in methods for deriving a HTRIE haplotype from an individual's genotype for the HTRIE gene and for determining an association between a HTRIE haplotype and a particular trait.
  • the invention provides a polynucleotide comprising a polymo ⁇ hic variant of a reference sequence for a HTRIE cDNA or a fragment thereof.
  • the reference sequence comprises SEQ ID NO:2 (Fig. 2) and the polymo ⁇ hic cDNA comprises thymine at a position corresponding to nucleotide 390 .
  • the polymo ⁇ hic variant comprises an additional polymo ⁇ hism of thymine at a position corresponding to nucleotide 531.
  • the invention provides a recombinant expression vector comprising one of the polymo ⁇ hic genomic variants operably linked to expression regulatory elements as well as a recombinant host cell transformed or transfected with the expression vector.
  • the recombinant vector and host cell may be used to express HTRIE for protein structure analysis and drug binding studies.
  • the invention provides methods, compositions, and kits for haplotyping and/or genotyping the HTRIE gene in an individual.
  • the methods involve identifying the nucleotide or nucleotide pair present at PS1 in one or both copies of the HTRIE gene from the individual.
  • the compositions contain oligonucleotide probes and primers designed to specifically hybridize to one or more target regions containing, or that are adjacent to, a polymo ⁇ hic site.
  • the methods and compositions for establishing the genotype or haplotype of an individual at the novel polymo ⁇ hic site described herein are useful for studying population diversity, anthropological lineage, the significance of diversity and lineage at the phenotypic level, paternity testing, forensic applications, and for identifying associations between the HTRIE genetic variation and a trait such as level of drug response or susceptibility to disease.
  • the invention provides a method for identifying an association between a genotype or haplotype and a trait.
  • the trait is susceptibility to a disease, severity of a disease, the staging of a disease or response to a drug.
  • Such methods have applicability in developing diagnostic tests and therapeutic treatments for neurologic and psychiatric diseases.
  • the present invention also provides nonhuman transgenic animals comprising one of the HTRIE genomic polymo ⁇ hic variants described herein and methods for producing such animals.
  • the transgenic animals are useful for studying expression of the HTRIE isogenes in vivo, for in vivo screening and testing of drugs targeted against HTRIE protein, and for testing the efficacy of therapeutic agents and compounds for neurologic and psychiatric diseases in a biological system.
  • the present invention also provides a computer system for storing and displaying polymo ⁇ hism data determined for the HTRIE gene.
  • the computer system comprises a computer processing unit; a display; and a database containing the polymo ⁇ hism data.
  • the polymo ⁇ hism data includes the polymo ⁇ hisms, the genotypes and the haplotypes identified for the HTRIE gene in a reference population.
  • the computer system is capable of producing a display showing HTRIE haplotypes organized according to their evolutionary relationships.
  • Figure 1 illustrates a reference sequence for the HTRIE gene (Genbank Version Number
  • FIG. 1 illustrates a reference sequence for the HTRIE coding sequence (contiguous lines;
  • Figure 3 illustrates a reference sequence for the HTRIE protein (contiguous lines; SEQ ID NO:3).
  • the present invention is based on the discovery of novel variants of the HTRIE gene.
  • the inventors herein discovered 1 novel polymo ⁇ hic site by characterizing the HTRIE gene found in genomic DNAs isolated from an Index Repository that contains immortalized cell lines from one chimpanzee and 93 human individuals.
  • the human individuals included a reference population of 79 unrelated individuals self-identified as belonging to one of four major population groups: Caucasian (22 individuals), African descent (20 individuals) Asian (20 individuals) Hispanic/Latino (17 individuals). To the extent possible, the members of this reference population were organized into population subgroups by the self-identified ethnogeographic origin of their four grandparents as shown in Table 1 below.
  • the Index Repository contains three unrelated indigenous American Indians (one from each of North, Central and South America), one three-generation Caucasian family (from the CEPH Utah cohort) and one two-generation African- American family.
  • the inventors herein Using the HTRIE genotypes identified in the Index Repository and the methodology described in the Examples below, the inventors herein also determined the haplotypes found on each chromosome for most human members of this repository.
  • the HTRIE genotypes and haplotypes found in the repository include those shown in Tables 4 and 5, respectively.
  • the polymo ⁇ hism and haplotype data disclosed herein are useful for studying population diversity, anthropological lineage, the significance of diversity and lineage at the phenotypic level, paternity testing, forensic applications, and for identifying associations between the HTRIE genetic variation and a trait such as level of drug response or susceptibility to disease.
  • Allele - A particular form of a genetic locus, distinguished from other forms by its particular nucleotide sequence.
  • Candidate Gene - A gene which is hypothesized to be responsible for a disease, condition, or the response to a treatment, or to be correlated with one of these.
  • Gene - A segment of DNA that contains all the information for the regulated biosynthesis of an RNA product, including promoters, exons, introns, and other untranslated regions that control expression.
  • Genotype An unphased 5 ' to 3 ' sequence of nucleotide pair(s) found at one or more polymo ⁇ hic sites in a locus on a pair of homologous chromosomes in an individual.
  • genotype includes a full-genotype and/or a sub-genotype as described below.
  • Full-genotype The unphased 5' to 3' sequence of nucleotide pairs found at all known polymo ⁇ hic sites in a locus on a pair of homologous chromosomes in a single individual.
  • Sub-genotype The unphased 5 ' to 3 ' sequence of nucleotides seen at a subset of the known polymo ⁇ hic sites in a locus on a pair of homologous chromosomes in a single individual.
  • Genotyping A process for determining a genotype of an individual.
  • Haplotype A 5 ' to 3 ' sequence of nucleotides found at one or more polymo ⁇ hic sites in a locus on a single chromosome from a single individual.
  • haplotype includes a full- haplotype and/or a sub-haplotype as described below.
  • Full-haplotype The 5 ' to 3 ' sequence of nucleotides found at all known polymo ⁇ hic sites in a locus on a single chromosome from a single individual.
  • Sub-haplotype The 5 ' to 3' sequence of nucleotides seen at a subset of the known polymo ⁇ hic sites in a locus on a single chromosome from a single individual.
  • Haplotype pair The two haplotypes found for a locus in a single individual.
  • Haplotyping A process for determining one or more haplotypes in an individual and includes use of family pedigrees, molecular techniques and/or statistical inference.
  • Haplotype data Information concerning one or more of the following for a specific gene: a listing of the haplotype pairs in each individual in a population; a listing of the different haplotypes in a population; frequency of each haplotype in that or other populations, and any known associations between one or more haplotypes and a trait.
  • Isoform - A particular form of a gene, mRNA, cDNA or the protein encoded thereby, distinguished from other forms by its particular sequence and/or structure.
  • Isogene - One of the isoforms of a gene found in a population.
  • An isogene contains all of the polymo ⁇ hisms present in the particular isoform of the gene.
  • Isolated - As applied to a biological molecule such as RNA, DNA, oligonucleotide, or protein, isolated means the molecule is substantially free of other biological molecules such as nucleic acids, proteins, lipids, carbohydrates, or other material such as cellular debris and growth media. Generally, the term “isolated” is not intended to refer to a complete absence of such material or to absence of water, buffers, or salts, unless they are present in amounts that substantially interfere with the methods of the present invention. Locus - A location on a chromosome or DNA molecule corresponding to a gene or a physical or phenotypic feature.
  • Naturally-occurring A term used to designate that the object it is applied to, e.g., naturally- occurring polynucleotide or polypeptide, can be isolated from a source in nature and which has not been intentionally modified by man.
  • Nucleotide pair The nucleotides found at a polymo ⁇ hic site on the two copies of a chromosome from an individual.
  • Phased As applied to a sequence of nucleotide pairs for two or more polymo ⁇ hic sites in a locus, phased means the combination of nucleotides present at those polymo ⁇ hic sites on a single copy of the locus is known.
  • Polymorphism The sequence variation observed in an individual at a polymo ⁇ hic site.
  • Polymo ⁇ hisms include nucleotide substitutions, insertions, deletions and microsatellites and may, but need not, result in detectable differences in gene expression or protein function.
  • Polymorphism data Information concerning one or more of the following for a specific gene: location of polymo ⁇ hic sites; sequence variation at those sites; frequency of polymo ⁇ hisms in one or more populations; the different genotypes and/or haplotypes determined for the gene; frequency of one or more of these genotypes and/or haplotypes in one or more populations; any known association(s) between a trait and a genotype or a haplotype for the gene.
  • Polymorphism Database A collection of polymo ⁇ hism data arranged in a systematic or methodical way and capable of being individually accessed by electronic or other means.
  • Polynucleotide A nucleic acid molecule comprised of single-stranded RNA or DNA or comprised of complementary, double-stranded DNA.
  • Population Group A group of individuals sharing a common ethnogeographic origin.
  • Reference Population A group of subjects or individuals who are predicted to be representative of the genetic variation found in the general population. Typically, the reference population represents the genetic variation in the population at a certainty level of at least 85%, preferably at least 90%, more preferably at least 95% and even more preferably at least 99%.
  • Single Nucleotide Polymorphism (SNP) Typically, the specific pair of nucleotides observed at a single polymo ⁇ hic site. In rare cases, three or four nucleotides may be found.
  • Subject A human individual whose genotypes or haplotypes or response to treatment or disease state are to be determined.
  • Treatment A stimulus administered internally or externally to a subject.
  • Unphased As applied to a sequence of nucleotide pairs for two or more polymo ⁇ hic sites in a locus, unphased means the combination of nucleotides present at those polymo ⁇ hic sites on a single copy of the locus is not known.
  • the inventors herein have discovered 1 novel polymo ⁇ hic site in the HTRIE gene.
  • the polymo ⁇ hic sites identified by the inventors are referred to as PS 1-2 to designate the order in which they are located in the gene (see Table 3 below), with the novel polymo ⁇ hic site referred to as PS1.
  • the invention provides an isolated polynucleotide comprising a polymo ⁇ hic variant of the HTRIE gene or a fragment of the gene which contains the novel polymo ⁇ hic site described herein.
  • the nucleotide sequence of a variant HTRIE gene is identical to the reference genomic sequence for those portions of the gene examined, as described in the Examples below, except that it comprises a different nucleotide at the novel polymo ⁇ hic site PS 1 , and may also comprise an additional polymo ⁇ hism of thymine at PS2.
  • nucleotide sequence of a variant fragment of the HTRIE gene is identical to the corresponding portion of the reference sequence except for having a different nucleotide at the novel polymo ⁇ hic site described herein.
  • the invention specifically does not include polynucleotides comprising a nucleotide sequence identical to the reference sequence (or other reported HTRIE sequences) or to portions of the reference sequence (or other reported HTRIE sequences), except for genotyping oligonucleotides as described below.
  • polymo ⁇ hism in a variant gene or fragment is identified by aligning its sequence against SEQ ID NO: 1.
  • the polymo ⁇ hism comprises thymine at PS 1.
  • the polymo ⁇ hic variant comprises a naturally-occurring isogene of the HTRIE gene which is defined by any one of haplotypes 1 -3 shown in Table 5 below.
  • Polymo ⁇ hic variants of the invention may be prepared by isolating a clone containing the
  • HTRIE gene from a human genomic library.
  • the clone may be sequenced to determine the identity of the nucleotides at the polymo ⁇ hic sites described herein. Any particular variant claimed herein could be prepared from this clone by performing in vitro mutagenesis using procedures well-known in the art.
  • HTRIE isogenes may be isolated using any method that allows separation of the two "copies" of the HTRIE gene present in an individual, which, as readily understood by the skilled artisan, may be the same allele or different alleles. Separation methods include targeted in vivo cloning (TIVC) in yeast as described in WO 98/01573, U.S. Patent No. 5,866,404, and U.S. Patent No. 5,972,614.
  • TIVC targeted in vivo cloning
  • Another method which is described in U.S. Patent No. 5,972,614, uses an allele specific oligonucleotide in combination with primer extension and exonuclease degradation to generate hemizygous DNA targets.
  • Yet other methods are single molecule dilution (SMD) as described in Rua ⁇ o et al., Proc. Natl. Acad. Sci. 87:6296-6300, 1990; and allele specific PCR (Ruano et al., 17 Nucleic Acids. Res. 8392, 1989; Ruano et al., 19 Nucleic Acids Res. 6877-6882, 1991; Michalatos- Beloin et al, 24 Nucleic Acids Res.
  • SMD single molecule dilution
  • the invention also provides HTRIE genome anthologies, which are collections of HTRIE isogenes found in a given population.
  • the population may be any group of at least two individuals, including but not limited to a reference population, a population group, a family population, a clinical population, and a same sex population.
  • a HTRIE genome anthology may comprise individual HTRIE isogenes stored in separate containers such as microtest tubes, separate wells of a microtitre plate and the like. Alternatively, two or more groups of the HTRIE isogenes in the anthology may be stored in separate containers.
  • a preferred HTRIE genome anthology of the invention comprises a set of isogenes defined by the haplotypes shown in Table 5 below.
  • An isolated polynucleotide containing a polymo ⁇ hic variant nucleotide sequence of the invention may be operably linked to one or more expression regulatory elements in a recombinant expression vector capable of being propagated and expressing the encoded HTRIE protein in a prokaryotic or a eukaryotic host cell.
  • expression regulatory elements which may be used include, but are not limited to, the lac system, operator and promoter regions of phage lambda, yeast promoters, and promoters derived from vaccinia virus, adenovirus, retroviruses, or SV40.
  • regulatory elements include, but are not limited to, appropriate leader sequences, termination codons, polyadenylation signals, and other sequences required for the appropriate transcription and subsequent translation of the nucleic acid sequence in a given host cell.
  • the expression vector contains any additional elements necessary for its transfer to and subsequent replication in the host cell. Examples of such elements include, but are not limited to, origins of replication and selectable markers.
  • Such expression vectors are commercially available or are readily constructed using methods known to those in the art (e.g., F. Ausubel et al., 1987, in "Current Protocols in Molecular Biology", John Wiley and Sons, New York, New York).
  • Host cells which may be used to express the variant HTRIE sequences of the invention include, but are not limited to, eukaryotic and mammalian cells, such as animal, plant, insect and yeast cells, and prokaryotic cells, such as E. coli, or algal cells as known in the art.
  • the recombinant expression vector may be introduced into the host cell using any method known to those in the art including, but not limited to, microinjection, electroporation, particle bombardment, transduction, and transfection using DEAE- dextran, lipofection, or calcium phosphate (see e.g., Sambrook et al. (1989) in "Molecular Cloning. A Laboratory Manual", Cold Spring Harbor Press, Plainview, New York).
  • eukaryotic expression vectors that function in eukaryotic cells, and preferably mammalian cells, are used.
  • Non- limiting examples of such vectors include vaccinia virus vectors, adenovirus vectors, he ⁇ es virus vectors, and baculovirus transfer vectors.
  • Preferred eukaryotic cell lines include COS cells, CHO cells, HeLa cells, NIH/3T3 cells, and embryonic stem cells (Thomson, J. A. et al., 1998 Science 282: 1145-1147).
  • Particularly preferred host cells are mammalian cells.
  • HTRIE gene will produce HTRIE mRNAs varying from each other at any polymo ⁇ hic site retained in the spliced and processed mRNA molecules.
  • These mRNAs can be used for the preparation of a HTRIE cDNA comprising a nucleotide sequence which is a polymo ⁇ hic variant of the HTRIE reference coding sequence shown in Figure 2.
  • the invention also provides HTRIE mRNAs and corresponding cDNAs which comprise a nucleotide sequence that is identical to SEQ ID NO:2 (Fig.
  • RNA sequence except for having a polymo ⁇ hism of thymine at a position corresponding to nucleotide 390, and may also comprise an additional polymo ⁇ hism of thymine at a position corresponding to nucleotide 531. Fragments of these variant mRNAs and cDNAs are included in the scope of the invention, provided they contain the novel polymo ⁇ hism described herein.
  • the invention specifically excludes polynucleotides identical to previously identified and characterized HTRIE cDNAs and fragments thereof. Polynucleotides comprising a variant RNA or DNA sequence may be isolated from a biological sample using well-known molecular biological procedures or may be chemically synthesized.
  • Polymo ⁇ hic variants of fragments according to the invention comprise the novel polymo ⁇ hism identified herein and have a length of at least 10 nucleotides and may range up to the full length of the gene.
  • such fragments are between 100 and 3000 nucleotides in length, and more preferably between 200 and 2000 nucleotides in length, and most preferably between 500 and 1000 nucleotides in length.
  • nucleic acid molecules containing the HTRIE gene may be complementary double stranded molecules and thus reference to a particular site on the sense strand refers as well to the corresponding site on the complementary antisense strand.
  • reference may be made to the same polymo ⁇ hic site on either strand and an oligonucleotide may be designed to hybridize specifically to either strand at a target region containing the polymo ⁇ hic site.
  • the invention also includes single-stranded polynucleotides which are complementary to the sense strand of the HTRIE genomic variants described herein.
  • Polynucleotides comprising a polymo ⁇ hic gene variant or fragment may be useful for therapeutic pu ⁇ oses.
  • an expression vector encoding the isoform may be administered to the patient.
  • the patient may be one who lacks the HTRIE isogene encoding that isoform or may already have at least one copy of that isogene.
  • it may be desirable to decrease or block expression of a particular HTRIE isogene.
  • Expression of a HTRIE isogene may be turned off by transforming a targeted organ, tissue or cell population with an expression vector that expresses high levels of untranslatable mRNA for the isogene.
  • oligonucleotides directed against the regulatory regions (e.g., promoter, introns, enhancers, 3' untranslated region) of the isogene may block transcription. Oligonucleotides targeting the transcription initiation site, e.g., between positions -10 and +10 from the start site are preferred. Similarly, inhibition of transcription can be achieved using oligonucleotides that base-pair with region(s) of the isogene DNA to form triplex DNA (see e.g., Gee et al. in Huber, B.E. and B.I. Carr, Molecular and Immunologic Approaches, Futura Publishing Co., Mt. Kisco, N.Y., 1994).
  • Antisense oligonucleotides may also be designed to block translation of HTRIE mRNA transcribed from a particular isogene. It is also contemplated that ribozymes may be designed that can catalyze the specific cleavage of HTRIE mRNA transcribed from a particular isogene.
  • the oligonucleotides may be delivered to a target cell or tissue by expression from a vector introduced into the cell or tissue in vivo or ex vivo. Alternatively, the oligonucleotides may be formulated as a pharmaceutical composition for administration to the patient.
  • Oligoribonucleotides and/or oligodeoxynucleotides intended for use as antisense oligonucleotides may be modified to increase stability and half-life. Possible modifications include, but are not limited to phosphorothioate or 2' O-methyl linkages, and the inclusion of nontraditional bases such as inosine and queosine, as well as acetyl-, methyl-, thio-, and similarly modified forms of adenine, cytosine, guanine, thymine, and uracil which are not as easily recognized by endogenous nucleases.
  • Effect(s) of the polymo ⁇ hisms identified herein on expression of HTRIE may be investigated by preparing recombinant cells and/or nonhuman recombinant organisms, preferably recombinant animals, containing a polymo ⁇ hic variant of the HTRIE gene.
  • expression includes but is not limited to one or more of the following: transcription of the gene into precursor mRNA; splicing and other processing of the precursor mRNA to produce mature mRNA; mRNA stability; translation of the mature mRNA into HTRIE protein (including codon usage and tRNA availability); and glycosylation and/or other modifications of the translation product, if required for proper expression and function.
  • the desired HTRIE isogene may be introduced into the cell in a vector such that the isogene remains extrachromosomal. In such a situation, the gene will be expressed by the cell from the extrachromosomal location.
  • the HTRIE isogene is introduced into a cell in such a way that it recombines with the endogenous HTRIE gene present in the cell. Such recombination requires the occurrence of a double recombination event, thereby resulting in the desired HTRIE gene polymo ⁇ hism.
  • Vectors for the introduction of genes both for recombination and for extrachromosomal maintenance are known in the art, and any suitable vector or vector construct may be used in the invention.
  • HTRIE HTRIE co-precipitation
  • viral transduction for introducing DNA into cells
  • examples of cells into which the HTRIE isogene may be introduced include, but are not limited to, continuous culture cells, such as COS, NIH/3T3, and primary or culture cells of the relevant tissue type, i.e., they express the HTRIE isogene.
  • continuous culture cells such as COS, NIH/3T3, and primary or culture cells of the relevant tissue type, i.e., they express the HTRIE isogene.
  • Such recombinant cells can be used to compare the biological activities of the different protein variants.
  • Recombinant nonhuman organisms, i.e., transgenic animals, expressing a variant HTRIE gene are prepared using standard procedures known in the art.
  • a construct comprising the variant gene is introduced into a nonhuman animal or an ancestor of the animal at an embryonic stage, i.e., the one-cell stage, or generally not later than about the eight-cell stage.
  • Transgenic animals carrying the constructs of the invention can be made by several methods known to those having skill in the art.
  • One method involves transfecting into the embryo a retrovirus constructed to contain one or more insulator elements, a gene or genes of interest, and other components known to those skilled in the art to provide a complete shuttle vector harboring the insulated gene(s) as a transgene, see e.g., U.S. Patent No. 5,610,053.
  • Another method involves directly injecting a transgene into the embryo.
  • a third method involves the use of embryonic stem cells.
  • animals into which the HTRIE isogenes may be introduced include, but are not limited to, mice, rats, other rodents, and nonhuman primates (see “The Introduction of Foreign Genes into Mice” and the cited references therein, In: Recombinant DNA, Eds. J.D. Watson, M. Gilman, J. Witkowski, and M. Zoller; W.H. Freeman and Company, New York, pages 254-272).
  • Transgenic animals stably expressing a human HTRIE isogene and producing human HTRIE protein can be used as biological models for studying diseases related to abnormal HTRIE expression and/or activity, and for screening and assaying various candidate drugs, compounds, and treatment regimens to reduce the symptoms or effects of these diseases.
  • compositions for treating disorders affected by expression or function of a novel HTRIE isogene described herein.
  • the pharmaceutical composition may comprise any of the following active ingredients: a polynucleotide comprising one of these novel HTRIE isogenes; an antisense oligonucleotide directed against one of the novel HTRIE isogenes, a polynucleotide encoding such an antisense oligonucleotide, or another compound which inhibits expression of a novel HTRIE isogene described herein.
  • the composition contains the active ingredient in a therapeutically effective amount.
  • composition also comprises a pharmaceutically acceptable carrier, examples of which include, but are not limited to, saline, buffered saline, dextrose, and water.
  • a pharmaceutically acceptable carrier examples of which include, but are not limited to, saline, buffered saline, dextrose, and water.
  • Those skilled in the art may employ a formulation most suitable for the active ingredient, whether it is a polynucleotide, oligonucleotide, protein, peptide or small molecule antagonist.
  • the pharmaceutical composition may be administered alone or in combination with at least one other agent, such as a stabilizing compound.
  • Administration of the pharmaceutical composition may be by any number of routes including, but not limited to oral, intravenous, intramuscular, intra-arterial, intramedullary, intrathecal, intraventricular, intradermal, transdermal, subcutaneous, intraperitoneal, intranasal, enteral, topical, sublingual, or rectal. Further details on techniques for formulation and administration may be found in the latest edition of Remington's Pharmaceutical Sciences (Maack Publishing Co., Easton, PA). For any composition, determination of the therapeutically effective dose of active ingredient and/or the appropriate route of administration is well within the capability of those skilled in the art.
  • the dose can be estimated initially either in cell culture assays or in animal models.
  • the animal model may also be used to determine the appropriate concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in humans.
  • the exact dosage will be determined by the practitioner, in light of factors relating to the patient requiring treatment, including but not limited to severity of the disease state, general health, age, weight and gender of the patient, diet, time and frequency of administration, other drugs being taken by the patient, and tolerance/response to the treatment.
  • the invention also provides compositions and methods for detecting the novel HTRIE polymo ⁇ hisms identified herein.
  • compositions comprise at least one HTRIE genotyping oligonucleotide.
  • a HTRIE genotyping oligonucleotide is a probe or primer capable of hybridizing to a target region that is located close to, or that contains, the novel polymo ⁇ hic site described herein.
  • the term "oligonucleotide” refers to a polynucleotide molecule having less than about 100 nucleotides.
  • a preferred oligonucleotide of the invention is 10 to 35 nucleotides long. More preferably, the oligonucleotide is between 15 and 30, and most preferably, between 20 and 25 nucleotides in length.
  • oligonucleotide may be comprised of any phosphorylation state of ribonucleotides, deoxyribonucleotides, and acyclic nucleotide derivatives, and other functionally equivalent derivatives.
  • oligonucleotides may have a phosphate-free backbone, which may be comprised of linkages such as carboxymefhyl, acetamidate, carbamate, polyamide (peptide nucleic acid (PNA)) and the like (Varma, R. in Molecular Biology and Biotechnology, A Comprehensive Desk Reference, Ed. R. Meyers, VCH Publishers, Inc. (1995), pages 617-620).
  • Oligonucleotides of the invention may be prepared by chemical synthesis using any suitable methodology known in the art, or may be derived from a biological sample, for example, by restriction digestion.
  • the oligonucleotides may be labeled, according to any technique known in the art, including use of radiolabels, fluorescent labels, enzymatic labels, proteins, haptens, antibodies, sequence tags and the like.
  • Genotyping oligonucleotides of the invention must be capable of specifically hybridizing to a target region of a HTRIE polynucleotide, i.e., a HTRIE isogene.
  • specific hybridization means the oligonucleotide forms an anti-parallel double-stranded structure with the target region under certain hybridizing conditions, while failing to form such a structure when incubated with a non-target region or a non-HTRlE polynucleotide under the same hybridizing conditions.
  • the oligonucleotide specifically hybridizes to the target region under conventional high stringency conditions.
  • oligonucleotide probes and primers suitable for detecting polymo ⁇ hisms in the HTRIE gene using the polymo ⁇ hism information provided herein in conjunction with the known sequence information for the HTRIE gene and routine techniques.
  • a nucleic acid molecule such as an oligonucleotide or polynucleotide is said to be a "perfect” or “complete” complement of another nucleic acid molecule if every nucleotide of one of the molecules is complementary to the nucleotide at the corresponding position of the other molecule.
  • a nucleic acid molecule is "substantially complementary” to another molecule if it hybridizes to that molecule with sufficient stability to remain in a duplex form under conventional low-stringency conditions. Conventional hybridization conditions are described, for example, by Sambrook J. et al., in Molecular Cloning, A Laboratory Manual, 2 nd Edition, Cold Spring Harbor Press, Cold Spring Harbor, NY (1989) and by Haymes, B.D.
  • an oligonucleotide primer may have a non-complementary fragment at its 5 ' end, with the remainder of the primer being complementary to the target region.
  • non-complementary nucleotides may be interspersed into the oligonucleotide probe or primer as long as the resulting probe or primer is still capable of specifically hybridizing to the target region.
  • Preferred genotyping oligonucleotides of the invention are allele-specific oligonucleotides.
  • ASO allele-specific oligonucleotide
  • allele-specificity will depend upon a variety of readily optimized stringency conditions, including salt and formamide concentrations, as well as temperatures for both the hybridization and washing steps.
  • Allele-specific oligonucleotide probes which usually provide good discrimination between different alleles are those in which a central position of the oligonucleotide probe aligns with the polymo ⁇ hic site in the target region (e.g., approximately the 7 th or 8 th position in a 15 mer, the 8 th or
  • HTRIE gene polymo ⁇ hisms comprises a nucleotide sequence, listed 5' to 3', selected from the group consisting of:
  • TTGAATACGCCAGGA (SEQ ID NO : 4 ) and its complement
  • TTGAATATGCCAGGA (SEQ ID NO: 5) and its complement.
  • An allele-specific oligonucleotide primer of the invention has a 3' terminal nucleotide, or preferably a 3' penultimate nucleotide, that is complementary to only one nucleotide of a particular SNP, thereby acting as a primer for polymerase-mediated extension only if the allele containing that nucleotide is present. Allele-specific oligonucleotide primers hybridizing to either the coding or noncoding strand are contemplated by the invention.
  • a preferred ASO primer for detecting HTRIE gene polymo ⁇ hisms comprises a nucleotide sequence, listed 5 ' to 3', selected from the group consisting of:
  • ATGCTATTGAATACG (SEQ ID NO:6); TCCTCTTCCTGGCGT (SEQ ID NO:7); ATGCTATTGAATATG (SEQ ID NO : 8 ) ; and TCCTCTTCCTGGCAT (SEQ ID NO:9).
  • genotyping oligonucleotides of the invention hybridize to a target region located one to several nucleotides downstream of one of the novel polymo ⁇ hic sites identified herein. Such oligonucleotides are useful in polymerase-mediated primer extension methods for detecting one of the novel polymo ⁇ hisms described herein and therefore such genotyping oligonucleotides are referred to herein as "primer-extension oligonucleotides".
  • the 3 ' -terminus of a primer-extension oligonucleotide is a deoxynucleotide complementary to the nucleotide located immediately adjacent to the polymo ⁇ hic site.
  • a particularly preferred oligonucleotide primer for detecting HTRIE gene polymo ⁇ hisms by primer extension terminates in a nucleotide sequence, listed 5 ' to 3 ', selected from the group consisting of:
  • CTATTGAATA SEQ ID NO:10
  • TCTTCCTGGC SEQ ID NO:ll
  • a composition contains two or more differently labeled genotyping oligonucleotides for simultaneously probing the identity of nucleotides at two or more polymo ⁇ hic sites. It is also contemplated that primer compositions may contain two or more sets of allele-specific primer pairs to allow simultaneous targeting and amplification of two or more regions containing a polymo ⁇ hic site.
  • HTRIE genotyping oligonucleotides of the invention may also be immobilized on or synthesized on a solid surface such as a microchip, bead, or glass slide (see, e.g., WO 98/20020 and WO 98/20019).
  • Immobilized genotyping oligonucleotides may be used in a variety of polymo ⁇ hism detection assays, including but not limited to probe hybridization and polymerase extension assays.
  • Immobilized HTRIE genotyping oligonucleotides of the invention may comprise an ordered array of oligonucleotides designed to rapidly screen a DNA sample for polymo ⁇ hisms in multiple genes at the same time.
  • the invention provides a kit comprising at least two genotyping oligonucleotides packaged in separate containers.
  • the kit may also contain other components such as hybridization buffer (where the oligonucleotides are to be used as a probe) packaged in a separate container.
  • the kit may contain, packaged in separate containers, a polymerase and a reaction buffer optimized for primer extension mediated by the polymerase, such as PCR.
  • HTRIE genotype and “HTRIE haplotype” mean the genotype or haplotype contains the nucleotide pair or nucleotide, respectively, that is present at the novel polymo ⁇ hic site described herein and may optionally also include the nucleotide pair or nucleotide present at one or more additional polymo ⁇ hic sites in the HTRIE gene.
  • the additional polymo ⁇ hic sites may be currently known polymo ⁇ hic sites or sites that are subsequently discovered.
  • One embodiment of the genotyping method involves isolating from the individual a nucleic acid mixture comprising the two copies of the HTRIE gene, or a fragment thereof, that are present in the individual, and determining the identity of the nucleotide pair at PS1 in the two copies to assign a HTRIE genotype to the individual.
  • the two "copies" of a gene in an individual may be the same allele or may be different alleles.
  • the identity of the nucleotide pair at PS2 is also determined.
  • the genotyping method comprises determining the identity of the nucleotide pair at each of PS1 and PS2.
  • the nucleic acid mixture is isolated from a biological sample taken from the individual, such as a blood sample or tissue sample.
  • tissue samples include whole blood, semen, saliva, tears, urine, fecal material, sweat, buccal, skin and hair.
  • the nucleic acid mixture may be comprised of genomic DNA, mRNA, or cDNA and, in the latter two cases, the biological sample must be obtained from an organ in which the HTRIE gene is expressed.
  • mRNA or cDNA preparations would not be used to detect polymo ⁇ hisms iocated in introns or in 5 ' and 3' nontranscribed regions. If a HTRIE gene fragment is isolated, it must contain the polymo ⁇ hic site(s) to be genotyped.
  • One embodiment of the haplotyping method comprises isolating from the individual a nucleic acid molecule containing only one of the two copies of the HTRIE gene, or a fragment thereof, that is present in the individual and determining in that copy the identity of the nucleotide at PS1 in that copy to assign a HTRIE haplotype to the individual.
  • the nucleic acid may be isolated using any method capable of separating the two copies of the HTRIE gene or fragment such as one of the methods described above for preparing HTRIE isogenes, with targeted in vivo cloning being the preferred approach.
  • any individual clone will only provide haplotype information on one of the two HTRIE gene copies present in an individual.
  • haplotyping method also comprises identifying the nucleotide at PS2. In a particularly preferred embodiment, the nucleotide at each of PS1 and PS2 is identified.
  • a HTRIE haplotype pair is determined for an individual by identifying the phased sequence of nucleotides at each of PS1 and PS2 in each copy of the HTRIE gene that is present in the individual.
  • the identifying step is preferably performed with each copy of the gene being placed in separate containers.
  • the two copies are labeled with different tags, or are otherwise separately distinguishable or identifiable, it could be possible in some cases to perform the method in the same container.
  • first and second copies of the gene are labeled with different first and second fluorescent dyes, respectively, and an allele-specific oligonucleotide labeled with yet a third different fluorescent dye is used to assay the polymo ⁇ hic site(s), then detecting a combination of the first and third dyes would identify the polymo ⁇ hism in the first gene copy while detecting a combination of the second and third dyes would identify the polymo ⁇ hism in the second gene copy.
  • the identity of a nucleotide (or nucleotide pair) at a polymo ⁇ hic site(s) may be determined by amplifying a target region(s) containing the polymo ⁇ hic site(s) directly from one or both copies of the HTRIE gene, or fragment thereof, and the sequence of the amplified region(s) determined by conventional methods. It will be readily appreciated by the skilled artisan that only one nucleotide will be detected at a polymo ⁇ hic site in individuals who are homozygous at that site, while two different nucleotides will be detected if the individual is heterozygous for that site.
  • the polymo ⁇ hism may be identified directly, known as positive-type identification, or by inference, referred to as negative-type identification.
  • a site may be positively determined to be either guanine or cytosine for an individual homozygous at that site, or both guanine and cytosine, if the individual is heterozygous at that site.
  • the site may be negatively determined to be not guanine (and thus cytosine/cytosine) or not cytosine (and thus guanine/guanine).
  • the identity of the allele(s) present at any of the polymo ⁇ hic sites described herein may be indirectly determined by genotyping a polymo ⁇ hic site not disclosed herein that is in linkage disequilibrium with the polymo ⁇ hic site that is of interest. Two sites are said to be in linkage disequilibrium if the presence of a particular variant at one site enhances the predictability of another variant at the second site (Stevens, JC 1999, Mol. Diag. 4: 309-17). Polymo ⁇ hic sites in linkage disequilibrium with the presently disclosed polymo ⁇ hic sites may be located in regions of the gene or in other genomic regions not examined herein.
  • Genotyping of a polymo ⁇ hic site in linkage disequilibrium with the novel polymo ⁇ hic sites described herein may be performed by, but is not limited to, any of the above-mentioned methods for detecting the identity of the allele at a polymo ⁇ hic site.
  • the target region(s) may be amplified using any oligonucleotide-directed amplification method, including but not limited to polymerase chain reaction (PCR) (U.S. Patent No. 4,965,188), ligase chain reaction (LCR) (Barany et al., Proc. Natl. Acad. Sci.
  • Oligonucleotide ligation assay OLA
  • Oligonucleotides useful as primers or probes in such methods should specifically hybridize to a region of the nucleic acid that contains or is adjacent to the polymo ⁇ hic site.
  • the oligonucleotides are between 10 and 35 nucleotides in length and preferably, between 15 and 30 nucleotides in length. Most preferably, the oligonucleotides are 20 to 25 nucleotides long. The exact length of the oligonucleotide will depend on many factors that are routinely considered and practiced by the skilled artisan.
  • nucleic acid amplification procedures may be used to amplify the target region including transcription-based amplification systems (U.S. Patent No. 5,130,238; EP 329,822; U.S. Patent No. 5,169,766, WO89/06700) and isothermal methods (Walker et al., Proc. Natl. Acad. Sci. USA 89:392-396, 1992).
  • a polymo ⁇ hism in the target region may also be assayed before or after amplification using one of several hybridization-based methods known in the art.
  • allele-specific oligonucleotides are utilized in performing such methods.
  • the allele-specific oligonucleotides may be used as differently labeled probe pairs, with one member of the pair showing a perfect match to one variant of a target sequence and the other member showing a perfect match to a different variant.
  • more than one polymo ⁇ hic site may be detected at once using a set of allele- specific oligonucleotides or oligonucleotide pairs.
  • the members of the set have melting temperatures within 5°C, and more preferably within 2°C, of each other when hybridizing to each of the polymo ⁇ hic sites being detected.
  • Hybridization of an allele-specific oligonucleotide to a target polynucleotide may be performed with both entities in solution, or such hybridization may be performed when either the oligonucleotide or the target polynucleotide is covalently or noncovalently affixed to a solid support. Attachment may be mediated, for example, by antibody-antigen interactions, poly-L-Lys, streptavidin or avidin-biotin, salt bridges, hydrophobic interactions, chemical linkages, UV cross-linking baking, etc. Allele-specific oligonucleotides may be synthesized directly on the solid support or attached to the solid support subsequent to synthesis.
  • Solid-supports suitable for use in detection methods of the invention include substrates made of silicon, glass, plastic, paper and the like, which may be formed, for example, into wells (as in 96-well plates), slides, sheets, membranes, fibers, chips, dishes, and beads.
  • the solid support may be treated, coated or derivatized to facilitate the immobilization of the allele-specific oligonucleotide or target nucleic acid.
  • the genotype or haplotype for the HTRIE gene of an individual may also be determined by hybridization of a nucleic acid sample containing one or both copies of the gene to nucleic acid arrays and subarrays such as described in WO 95/1 1995.
  • the arrays would contain a battery of allele- specific oligonucleotides representing each of the polymo ⁇ hic sites to be included in the genotype or haplotype.
  • polymo ⁇ hisms may also be determined using a mismatch detection technique, including but not limited to the RNase protection method using riboprobes (Winter et al., Proc. Natl. Acad. Sci. USA 82:7575, 1985; Meyers et al., Science 230:1242, 1985) and proteins which recognize nucleotide mismatches, such as the E. coli mutS protein (Modrich, P. Ann. Rev. Genet. 25:229-253, 1991).
  • riboprobes Winter et al., Proc. Natl. Acad. Sci. USA 82:7575, 1985; Meyers et al., Science 230:1242, 1985
  • proteins which recognize nucleotide mismatches such as the E. coli mutS protein (Modrich, P. Ann. Rev. Genet. 25:229-253, 1991).
  • variant alleles can be identified by single strand conformation polymo ⁇ hism (SSCP) analysis (Orita et al., Genomics 5:874-879, 1989; Humphries et al., in Molecular Diagnosis of Genetic Diseases, R. Elles, ed., pp. 321-340, 1996) or denaturing gradient gel electrophoresis (DGGE) (Wartell et al., Nucl. Acids Res. 18:2699-2706, 1990; Sheffield et al, Proc. Natl. Acad. Sci. USA 86:232-236, 1989).
  • SSCP single strand conformation polymo ⁇ hism
  • DGGE denaturing gradient gel electrophoresis
  • a polymerase-mediated primer extension method may also be used to identify the polymo ⁇ hism(s).
  • Several such methods have been described in the patent and scientific literature and include the "Genetic Bit Analysis” method (W092/15712) and the ligase/polymerase mediated genetic bit analysis (U.S. Patent 5,679,524. Related methods are disclosed in WO91/02087, WO90/09455, W095/17676, U.S. Patent Nos. 5,302,509, and 5,945,283. Extended primers containing a polymo ⁇ hism may be detected by mass spectrometry as described in U.S. Patent No. 5,605,798.
  • Another primer extension method is allele-specific PCR (Ruano et al., Nucl. Acids Res. 17:8392,
  • the haplotyping prediction method comprises identifying a HTRIE genotype for the individual at PS1 and PS2, enumerating all possible haplotype pairs which are consistent with the genotype, accessing data containing HTRIE haplotype pairs identified in a reference population, and assigning a haplotype pair to the individual that is consistent with the data.
  • the reference haplotype pairs include the HTRIE haplotype pairs shown in Table 4.
  • the reference population should be composed of randomly-selected individuals representing the major ethnogeographic groups of the world.
  • a preferred reference population allows the detection of any haplotype whose frequency is at least 10% with about
  • a particularly preferred reference population includes a 3-generation family representing one or more of the four population groups to serve as controls for checking quality of haplotyping procedures.
  • the haplotype frequency data for each ethnogeographic group is examined to determine whether it is consistent with Hardy- Weinberg equilibrium.
  • a statistically significant difference between the observed and expected haplotype frequencies could be due to one or more factors including significant inbreeding in the population group, strong selective pressure on the gene, sampling bias, and/or errors in the genotyping process. If large deviations from Hardy- Weinberg equilibrium are observed in an ethnogeographic group, the number of individuals in that group can be increased to see if the deviation is due to a sampling bias. If a larger sample size does not reduce the difference between observed and expected haplotype pair frequencies, then one may wish to consider haplotyping the individual using a direct haplotyping method such as, for example, CLASPER System TM technology (U.S. Patent No. 5,866,404), SMD, or allele-specific long- range PCR (Michalotos-Beloin et al. Nucleic Acids Res. 24:4841-4843, 1996).
  • CLASPER System TM technology U.S. Patent No. 5,866,404
  • SMD SMD
  • allele-specific long- range PCR Moichalot
  • the assigning step involves performing the following analysis. First, each of the possible haplotype pairs is compared to the haplotype pairs in the reference population. Generally, only one of the haplotype pairs in the reference population matches a possible haplotype pair and that pair is assigned to the individual. Occasionally, only one haplotype represented in the reference haplotype pairs is consistent with a possible haplotype pair for an individual, and in such cases the individual is assigned a haplotype pair containing this known haplotype and a new haplotype derived by subtracting the known haplotype from the possible haplotype pair.
  • the individual is preferably haplotyped using a direct molecular haplotyping method such as, for example, CLASPER System technology (U.S. Patent No. 5,866,404), SMD, or allele-specific long-range PCR (Michalotos-Beloin et al. Nucleic Acids Res. 24:4841-4843, 1996).
  • a direct molecular haplotyping method such as, for example, CLASPER System technology (U.S. Patent No. 5,866,404), SMD, or allele-specific long-range PCR (Michalotos-Beloin et al. Nucleic Acids Res. 24:4841-4843, 1996).
  • the invention also provides a method for determining the frequency of a HTRIE genotype or HTRIE haplotype in a population.
  • the method comprises determining the genotype or the haplotype pair for the HTRIE gene that is present in each member of the population, wherein the genotype or haplotype comprises the nucleotide pair or nucleotide detected at PS1 in the HTRIE gene; and calculating the frequency any particular genotype or haplotype is found in the population.
  • the population may be a reference population, a family population, a same sex population, a population group, a trait population (e.g., a group of individuals exhibiting a trait of interest such as a medical condition or response to a therapeutic treatment).
  • frequency data for HTRIE genotypes and/or haplotypes found in a reference population are used in a method for identifying an association between a trait and a HTRIE genotype or a HTRIE haplotype.
  • the trait may be any detectable phenotype, including but not limited to susceptibility to a disease or response to a treatment.
  • the method involves obtaining data on the frequency of the genotype(s) or haplotype(s) of interest in a reference population as well as in a population exhibiting the trait.
  • Frequency data for one or both of the reference and trait populations may be obtained by genotyping or haplotyping each individual in the populations using one of the methods described above.
  • the haplotypes for the trait population may be determined directly or, alternatively, by the predictive genotype to haplotype approach described above.
  • the frequency data for the reference and/or trait populations is obtained by accessing previously determined frequency data, which may be in written or electronic form.
  • the frequency data may be present in a database that is accessible by a computer. Once the frequency data is obtained, the frequencies of the genotype(s) or haplotype(s) of interest in the reference and trait populations are compared. In a preferred embodiment, the frequencies of all genotypes and/or haplotypes observed in the populations are compared.
  • the trait is predicted to be associated with that HTRIE genotype or haplotype.
  • the HTRIE genotype or haplotype being compared in the trait and reference populations is selected from the full-genotypes and full-haplotypes shown in Tables 4 and 5, respectively, or from sub-genotypes and sub-haplotypes derived from these genotypes and haplotypes.
  • the trait of interest is a clinical response exhibited by a patient to some therapeutic treatment, for example, response to a drug targeting HTRIE or response to a therapeutic treatment for a medical condition.
  • medical condition includes but is not limited to any condition or disease manifested as one or more physical and/or psychological symptoms for which treatment is desirable, and includes previously and newly identified diseases and other disorders.
  • clinical response means any or all of the following: a quantitative measure of the response, no response, and adverse response (i.e., side effects).
  • clinical population In order to deduce a correlation between clinical response to a treatment and a HTRIE genotype or haplotype, it is necessary to obtain data on the clinical responses exhibited by a population of individuals who received the treatment, hereinafter the "clinical population".
  • This clinical data may be obtained by analyzing the results of a clinical trial that has already been run and/or the clinical data may be obtained by designing and carrying out one or more new clinical trials.
  • the term "clinical trial” means any research study designed to collect clinical data on responses to a particular treatment, and includes but is not limited to phase I, phase II and phase III clinical trials. Standard methods are used to define the patient population and to enroll subjects.
  • the individuals included in the clinical population have been graded for the existence of the medical condition of interest. This is important in cases where the symptom(s) being presented by the patients can be caused by more than one underlying condition, and where treatment of the underlying conditions are not the same. An example of this would be where patients experience breathing difficulties that are due to either asthma or respiratory infections. If both sets were treated with an asthma medication, there would be a spurious group of apparent non-responders that did not actually have asthma. These people would affect the ability to detect any correlation between haplotype and treatment outcome.
  • This grading of potential patients could employ a standard physical exam or one or more lab tests. Alternatively, grading of patients could use haplotyping for situations where there is a strong correlation between haplotype pair and disease susceptibility or severity.
  • the therapeutic treatment of interest is administered to each individual in the trial population and each individual's response to the treatment is measured using one or more predetermined criteria. It is contemplated that in many cases, the trial population will exhibit a range of responses and that the investigator will choose the number of responder groups (e.g., low, medium, high) made up by the various responses.
  • the HTRIE gene for each individual in the trial population is genotyped and/or haplotyped, which may be done before or after administering the treatment.
  • correlations between individual response and HTRIE genotype or haplotype content are created. Correlations may be produced in several ways. In one method, individuals are grouped by their HTRIE genotype or haplotype (or haplotype pair) (also referred to as a polymo ⁇ hism group), and then the averages and standard deviations of clinical responses exhibited by the members of each polymo ⁇ hism group are calculated.
  • a second method for finding correlations between HTRIE haplotype content and clinical responses uses predictive models based on error-minimizing optimization algorithms.
  • One of many possible optimization algorithms is a genetic algorithm (R. Judson, "Genetic Algorithms and Their Uses in Chemistry” in Reviews in Computational Chemistry, Vol. 10, pp. 1-73, K. B. Lipkowitz and D. B. Boyd, eds. (VCH Publishers, New York, 1997). Simulated annealing (Press et al, "Numerical
  • Correlations may also be analyzed using analysis of variation (ANOVA) techniques to determine how much of the variation in the clinical data is explained by different subsets of the polymo ⁇ hic sites in the HTRIE gene.
  • ANOVA analysis of variation
  • PCT/US00/17540 ANOVA is used to test hypotheses about whether a response variable is caused by or correlated with one or more traits or variables that can be measured (Fisher and vanBelle, supra, Ch. 10).
  • a mathematical model may be readily constructed by the skilled artisan that predicts clinical response as a function of HTRIE genotype or haplotype content.
  • the model is validated in one or more follow-up clinical trials designed to test the model.
  • the identification of an association between a clinical response and a genotype or haplotype (or haplotype pair) for the HTRIE gene may be the basis for designing a diagnostic method to determine those individuals who will or will not respond to the treatment, or alternatively, will respond at a lower level and thus may require more treatment, i.e., a greater dose of a drug.
  • the diagnostic method may take one of several forms: for example, a direct DNA test (i.e., genotyping or haplotyping one or more of the polymo ⁇ hic sites in the HTRIE gene), a serological test, or a physical exam measurement.
  • a direct DNA test i.e., genotyping or haplotyping one or more of the polymo ⁇ hic sites in the HTRIE gene
  • serological test i.e., a serological test
  • a physical exam measurement i.e., a physical exam measurement.
  • this diagnostic method uses the predictive haplotyping method described above.
  • any or all analytical and mathematical operations involved in practicing the methods of the present invention may be implemented by a computer.
  • the computer may execute a program that generates views (or screens) displayed on a display device and with which the user can interact to view and analyze large amounts of information relating to the HTRIE gene and its genomic variation, including chromosome location, gene structure, and gene family, gene expression data, polymo ⁇ hism data, genetic sequence data, and clinical data population data (e.g., data on ethnogeographic origin, clinical responses, genotypes, and haplotypes for one or more populations).
  • the HTRIE polymo ⁇ hism data described herein may be stored as part of a relational database (e.g., an instance of an Oracle database or a set of ASCII flat files).
  • polymo ⁇ hism data may be stored on the computer's hard drive or may, for example, be stored on a CD ROM or on one or more other storage devices accessible by the computer.
  • the data may be stored on one or more databases in communication with the computer via a network.
  • EXAMPLE 1 This example illustrates examination of various regions of the HTRIE gene for polymo ⁇ hic sites.
  • the following target regions of the HTRIE gene were amplified using the PCR primer pairs listed below, with the sequences presented in the 5 ' to 3 ' direction and nucleotide positions shown for each region corresponding to the indicated GenBank Accession No.
  • Reverse Primer complement of 1248-1218 TGAATGCACCCAGAATCAGCC (SEQ ID NO: 15) 520 nt PCR product
  • Fragment 3 Forward Primer: 1069-1094 TTTCTGTGTGTCTGACTTCTCCACC (SEQ ID NO: 16) Reverse Primer: complement of 1517- 1496 AATAAGTTGCACCCCTTACCCC (SEQ ID NO: 17) 449 nt PCR product Fragment 4 Forward Primer: 1242-1263 GCATTCATTTTATCCTGGCTGC (SEQ ID NO: 18) Reverse Primer: complement of 1644-1623 CCAGAGGTAGAAAACAGCACGC (SEQ ID NO: 19) 403 nt PCR product
  • Amplification profile 94°C - 2 min. 1 cycle
  • PCR products were purified by Solid Phase Reversible Immobilization using the protocol developed by the Whitehead Genome Center. A detailed protocol can be found at http://www.genome.wi.mit.edu/sequencing/protocols/pure/SPRI_pcr.html.
  • Polymo ⁇ hic sites PS1 and PS2 have previously been mapped to nucleotide positions 956 and 1097 respectively, corresponding to GenBank Accession No. M91467.1 in the U.S. Provisional Application Number 60/160,280 filed on October 19, 1999.
  • EXAMPLE 2 This example illustrates analysis of the HTRIE polymo ⁇ hisms identified in the Index Repository for human genotypes and haplotypes.
  • the different genotypes containing these polymo ⁇ hisms that were observed in the reference population are shown in Table 4 below, with the haplotype pair indicating the combination of haplotypes determined for the individual using the haplotype derivation protocol described below.
  • Table 4 homozygous positions are indicated by one nucleotide and heterozygous positions are indicated by two nucleotides. Missing nucleotides in any given genotype in Table 4 were inferred based on linkage disequilibrium and/or Mendelian inheritance.
  • haplotype pairs shown in Table 4 were estimated from the unphased genotypes using an extension of Clark's algorithm (Clark, A.G. (1990) Mol Bio Evol 7, 1 11-122), as described in U.S. Provisional Application Serial No. 60/198,340 entitled "A Method and System for Determining Haplotypes from a Collection of Polymo ⁇ hisms".
  • haplotypes are assigned directly from individuals who are homozygous at all sites or heterozygous at no more than one of the variable sites.
  • the list of haplotypes is augmented with haplotypes obtained from a three- generation Caucasian family and a two-generation African- American family. This list of haplotypes is then used to deconvolute the unphased genotypes in the remaining (multiply heterozygous) individuals.

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Abstract

Polynucleotides comprising 1 novel single nucleotide polymorphisms in the human 5-hydroxytryptamine (serotonin) receptor 1E (HTR1E) gene are described. Compositions and methods for detecting one or more of these polymorphisms are also disclosed. In addition, various genotypes and haplotypes for the HTR1E gene that exist in the population are described.

Description

DRUG TARGET ISOGENES: POLYMORPHISMS IN THE 5-HYDROXYTRYPTAMINE (SEROTONIN) RECEPTOR IE GENE
RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application Serial No. 60/160,280 filed
October 19, 1999.
FIELD OF THE INVENTION
This invention relates to variation in genes that encode pharmaceutically important proteins. In particular, this invention provides genetic variants of the human 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) gene and methods for identifying which variant(s) of this gene is/are possessed by an individual.
BACKGROUND OF THE INVENTION Current methods for identifying pharmaceuticals to treat disease often start by identifying, cloning, and expressing an important target protein related to the disease. A determination of whether an agonist or antagonist is needed to produce an effect that may benefit a patient with the disease is then made. Then, vast numbers of compounds are screened against the target protein to find new potential drugs. The desired outcome of this process is a drug that is specific for the target, thereby reducing the incidence of the undesired side effects usually caused by a compound's activity at non- intended targets.
What this approach fails to consider, however, is that natural variability exists in any and every population with respect to a particular protein. A target protein currently used to screen drugs typically is expressed by a gene cloned from an individual who was arbitrarily selected. However, the nucleotide sequence of a particular gene may vary tremendously among individuals. Subtle alteration(s) in the primary nucleotide sequence of a gene encoding a target protein may be manifested as significant variation in expression of or in the structure and/or function of the protein. Such alterations may explain the relatively high degree of uncertainty inherent in treatment of individuals with drugs whose design is based upon a single representative example of the target. For example, it is well-established that some classes of drugs frequently have lower efficacy in some individuals than others, which means such individuals and their physicians must weigh the possible benefit of a larger dosage against a greater risk of side effects. In addition, variable information on the biological function or effects of a particular protein may be due to different scientists unknowingly studying different iso forms of the gene encoding the protein. Thus, information on the type and frequency of genomic variation that exists for pharmaceutically important proteins would be useful.
The organization of single nucleotide variations (polymorphisms) in the primary sequence of a gene into one of the limited number of combinations that exist as units of inheritance is termed a haplotype. Each haplotype therefore contains significantly more information than individual unorganized polymorphisms. Haplotypes provide an accurate measurement of the genomic variation in the two chromosomes of an individual and can be used to identify and distinguish between isoforms of genes coding for drug targets.
It is well-established that many diseases are associated with specific variations in gene sequences. However while there are examples in which individual polymorphisms act as genetic markers for a particular phenotype, in other cases an individual polymorphism may be found in a variety of genomic backgrounds and therefore shows no definitive coupling between the polymorphism and the causative site for the phenotype (Clark AG et al. 1998 Am J Hum Genet
63:595-612; Ulbrecht M et al. 2000 Am J Respir Crit Care Med 161: 469-74). In addition, the marker may be predictive in some populations, but not in other populations (Clark AG et al. 1998 supra). In these instances, a haplotype will provide a superior genetic marker for the phenotype (Clark AG et al. 1998 supra; Ulbrecht M et al. 2000, supra; Ruaήo G & Stephens JC Gen EngNews 19 (21), December 1999).
Analysis of the association between each observed haplotype and a particular phenotype permits ranking of each haplotype by its statistical power of prediction for the phenotype. Haplotypes found to be strongly associated with the phenotype can then have that positive association confirmed by alternative methods to minimize false positives. For a gene suspected to be associated with a particular phenotype, if no observed haplotypes for that gene show association with the phenotype of interest, then it may be inferred that variation in the gene has little, if any, involvement with that phenotype (Ruano & Stephens 1999, supra). Thus, information on the observed haplotypes and their frequency of occurrence in various population groups will be useful in a variety of research and clinical applications. One possible drug target for the treatment of neurologic and psychiatric diseases is the 5- hydroxytryptamine (serotonin) receptor IE (HTRIE) gene or its encoded product. HTRIE, also known as the 5-HT-1E receptor, is a G-protein-coupled receptor and is one of several 5-HT-l receptor subtypes for serotonin (5-hydroxytryptamine or 5-HT), a key neurotransmitter implicated in various cognitive and behavioral functions including, mood, sleep, appetite, depression and learning (for review, see Pauwels, P J., Gen. Pharmacol. 29:293-303, 1997; Hasler, W.L., Dig. Dis. Sci. 44: 108S- 113S, 1999). HTRIE is expressed in the brain, at higher levels in the caudate (72%) and putamen (64%), and in lower levels in the hippocampus (16%) (Lowther et al., Eur. J. Pharmacol. 1992 Nov 3;222(1): 137-42). Based on their studies on neuroblastomas, Pranzatelli et al (Exp Neurol 1992 Mar;l 15(3):423-7) have suggested that HTRIE may have clinical implications as a tumor marker. They studied the various types of seratonin receptors in thirteen neuroblastomas from children and reported that among other serotonin receptors, only HTRIE and HT-3 receptors were detected in neuroblastomas. The 5-hydroxytryptamine (serotonin) receptor IE gene is located on chromosome 6ql4-ql5 and contains 1 exon that encodes a 365 amino acid protein. Reference sequences for the HTRIE gene (GenBank Accession No:Zl 1166.1 ; SEQ ID NO: 1), coding sequence, and protein are shown in Figures 1, 2 and 3, respectively. One single nucleotide polymorphism of a cytosine or thymine at nucleotide position 878 in
Figure 1 has been reported in the NCBI SNP Database (Ref SNP#6302) released on July 15, 1999. Because of the potential for polymorphisms in the HTRIE gene to affect the expression and function of the encoded protein, it would be useful to determine whether additional polymorphisms exist in the HTRIE gene, as well as how such polymorphisms are combined in different copies of the gene. Such information would be useful for studying the biological function of HTRIE as well as in identifying drugs targeting this protein for the treatment of disorders related to its abnormal expression or function.
SUMMARY OF THE INVENTION Accordingly, the inventors herein have discovered 1 novel polymoφhic site in the HTRIE gene. This polymoφhic site (PS) corresponds to nucleotide position 737 in GenBank Accession Number Z 11166.1 , and is operationally designated herein as PS 1. The polymoφhism at PS 1 is cytosine or thymine. In addition, the inventors have determined the identity of the alternative nucleotide present at this site, as well as at the previously identified site at nucleotide 878 (PS2), in a human reference population of 79 unrelated individuals self-identified as belonging to one of four major population groups: African descent, Asian, Caucasian and Hispanic/Latino. It is believed that HTR IE-encoding polynucleotides containing the novel polymoφhic site reported herein will be useful in studying the expression and biological function of HTRIE, as well as in developing drugs targeting this protein. In addition, information on the combinations of polymoφhisms in the HTRIE gene may have diagnostic and forensic applications.
Thus, in one embodiment, the invention provides an isolated polynucleotide comprising a nucleotide sequence which is a polymoφhic variant of a reference sequence for the HTRIE gene or a fragment thereof. The reference sequence comprises SEQ ID NO: 1 and the polymoφhic variant comprises thymine at PS 1. In a preferred embodiment, the polymoφhic variant comprises an additional polymoφhism of thymine at PS2. A particularly preferred polymoφhic variant is a naturally-occurring isoform (also referred to herein as an "isogene") of the HTRIE gene. A HTRIE isogene of the invention comprises cytosine or thymine at PS1 and cytosine or thymine at PS2. The invention also provides a collection of HTRIE isogenes, referred to herein as a HTRIE genome anthology. A HTRIE isogene may be defined by the combination and order of these polymoφhisms in the isogene, which is referred to herein as a HTRIE haplotype. Thus, the invention also provides data on the number of different HTRIE haplotypes found in the above four population groups. This haplotype data is useful in methods for deriving a HTRIE haplotype from an individual's genotype for the HTRIE gene and for determining an association between a HTRIE haplotype and a particular trait.
In another embodiment, the invention provides a polynucleotide comprising a polymoφhic variant of a reference sequence for a HTRIE cDNA or a fragment thereof. The reference sequence comprises SEQ ID NO:2 (Fig. 2) and the polymoφhic cDNA comprises thymine at a position corresponding to nucleotide 390 . In a preferred embodiment, the polymoφhic variant comprises an additional polymoφhism of thymine at a position corresponding to nucleotide 531.
Polynucleotides complementary to these HTRIE genomic and cDNA variants are also provided by the invention. In other embodiments, the invention provides a recombinant expression vector comprising one of the polymoφhic genomic variants operably linked to expression regulatory elements as well as a recombinant host cell transformed or transfected with the expression vector. The recombinant vector and host cell may be used to express HTRIE for protein structure analysis and drug binding studies.
In other embodiments, the invention provides methods, compositions, and kits for haplotyping and/or genotyping the HTRIE gene in an individual. The methods involve identifying the nucleotide or nucleotide pair present at PS1 in one or both copies of the HTRIE gene from the individual. The compositions contain oligonucleotide probes and primers designed to specifically hybridize to one or more target regions containing, or that are adjacent to, a polymoφhic site. The methods and compositions for establishing the genotype or haplotype of an individual at the novel polymoφhic site described herein are useful for studying population diversity, anthropological lineage, the significance of diversity and lineage at the phenotypic level, paternity testing, forensic applications, and for identifying associations between the HTRIE genetic variation and a trait such as level of drug response or susceptibility to disease.
In yet another embodiment, the invention provides a method for identifying an association between a genotype or haplotype and a trait. In preferred embodiments, the trait is susceptibility to a disease, severity of a disease, the staging of a disease or response to a drug. Such methods have applicability in developing diagnostic tests and therapeutic treatments for neurologic and psychiatric diseases.
The present invention also provides nonhuman transgenic animals comprising one of the HTRIE genomic polymoφhic variants described herein and methods for producing such animals. The transgenic animals are useful for studying expression of the HTRIE isogenes in vivo, for in vivo screening and testing of drugs targeted against HTRIE protein, and for testing the efficacy of therapeutic agents and compounds for neurologic and psychiatric diseases in a biological system. The present invention also provides a computer system for storing and displaying polymoφhism data determined for the HTRIE gene. The computer system comprises a computer processing unit; a display; and a database containing the polymoφhism data. The polymoφhism data includes the polymoφhisms, the genotypes and the haplotypes identified for the HTRIE gene in a reference population. In a preferred embodiment, the computer system is capable of producing a display showing HTRIE haplotypes organized according to their evolutionary relationships.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a reference sequence for the HTRIE gene (Genbank Version Number
Zl 1166.1; contiguous lines; SEQ ID NO:l), with the start and stop positions of each region of coding sequence indicated below the sequence by the numbers within the brackets and the polymoφhic sites and polymoφhisms identified by Applicants in a reference population indicated by the variant nucleotide positioned below the polymoφhic site in the sequence. Figure 2 illustrates a reference sequence for the HTRIE coding sequence (contiguous lines;
SEQ ID NO:2), with the polymoφhic sites and polymoφhisms identified by Applicants in a reference population indicated by the variant nucleotide positioned below the polymoφhic site in the sequence.
Figure 3 illustrates a reference sequence for the HTRIE protein (contiguous lines; SEQ ID NO:3).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is based on the discovery of novel variants of the HTRIE gene. As described in more detail below, the inventors herein discovered 1 novel polymoφhic site by characterizing the HTRIE gene found in genomic DNAs isolated from an Index Repository that contains immortalized cell lines from one chimpanzee and 93 human individuals. The human individuals included a reference population of 79 unrelated individuals self-identified as belonging to one of four major population groups: Caucasian (22 individuals), African descent (20 individuals) Asian (20 individuals) Hispanic/Latino (17 individuals). To the extent possible, the members of this reference population were organized into population subgroups by the self-identified ethnogeographic origin of their four grandparents as shown in Table 1 below.
Figure imgf000007_0001
In addition, the Index Repository contains three unrelated indigenous American Indians (one from each of North, Central and South America), one three-generation Caucasian family (from the CEPH Utah cohort) and one two-generation African- American family.
Using the HTRIE genotypes identified in the Index Repository and the methodology described in the Examples below, the inventors herein also determined the haplotypes found on each chromosome for most human members of this repository. The HTRIE genotypes and haplotypes found in the repository include those shown in Tables 4 and 5, respectively. The polymoφhism and haplotype data disclosed herein are useful for studying population diversity, anthropological lineage, the significance of diversity and lineage at the phenotypic level, paternity testing, forensic applications, and for identifying associations between the HTRIE genetic variation and a trait such as level of drug response or susceptibility to disease.
In the context of this disclosure, the following terms shall be defined as follows unless otherwise indicated:
Allele - A particular form of a genetic locus, distinguished from other forms by its particular nucleotide sequence.
Candidate Gene - A gene which is hypothesized to be responsible for a disease, condition, or the response to a treatment, or to be correlated with one of these. Gene - A segment of DNA that contains all the information for the regulated biosynthesis of an RNA product, including promoters, exons, introns, and other untranslated regions that control expression.
Genotype - An unphased 5 ' to 3 ' sequence of nucleotide pair(s) found at one or more polymoφhic sites in a locus on a pair of homologous chromosomes in an individual. As used herein, genotype includes a full-genotype and/or a sub-genotype as described below.
Full-genotype - The unphased 5' to 3' sequence of nucleotide pairs found at all known polymoφhic sites in a locus on a pair of homologous chromosomes in a single individual.
Sub-genotype - The unphased 5 ' to 3 ' sequence of nucleotides seen at a subset of the known polymoφhic sites in a locus on a pair of homologous chromosomes in a single individual. Genotyping - A process for determining a genotype of an individual.
Haplotype - A 5 ' to 3 ' sequence of nucleotides found at one or more polymoφhic sites in a locus on a single chromosome from a single individual. As used herein, haplotype includes a full- haplotype and/or a sub-haplotype as described below.
Full-haplotype - The 5 ' to 3 ' sequence of nucleotides found at all known polymoφhic sites in a locus on a single chromosome from a single individual.
Sub-haplotype - The 5' to 3' sequence of nucleotides seen at a subset of the known polymoφhic sites in a locus on a single chromosome from a single individual.
Haplotype pair - The two haplotypes found for a locus in a single individual.
Haplotyping - A process for determining one or more haplotypes in an individual and includes use of family pedigrees, molecular techniques and/or statistical inference.
Haplotype data - Information concerning one or more of the following for a specific gene: a listing of the haplotype pairs in each individual in a population; a listing of the different haplotypes in a population; frequency of each haplotype in that or other populations, and any known associations between one or more haplotypes and a trait. Isoform - A particular form of a gene, mRNA, cDNA or the protein encoded thereby, distinguished from other forms by its particular sequence and/or structure.
Isogene - One of the isoforms of a gene found in a population. An isogene contains all of the polymoφhisms present in the particular isoform of the gene.
Isolated - As applied to a biological molecule such as RNA, DNA, oligonucleotide, or protein, isolated means the molecule is substantially free of other biological molecules such as nucleic acids, proteins, lipids, carbohydrates, or other material such as cellular debris and growth media. Generally, the term "isolated" is not intended to refer to a complete absence of such material or to absence of water, buffers, or salts, unless they are present in amounts that substantially interfere with the methods of the present invention. Locus - A location on a chromosome or DNA molecule corresponding to a gene or a physical or phenotypic feature.
Naturally-occurring - A term used to designate that the object it is applied to, e.g., naturally- occurring polynucleotide or polypeptide, can be isolated from a source in nature and which has not been intentionally modified by man.
Nucleotide pair - The nucleotides found at a polymoφhic site on the two copies of a chromosome from an individual. Phased - As applied to a sequence of nucleotide pairs for two or more polymoφhic sites in a locus, phased means the combination of nucleotides present at those polymoφhic sites on a single copy of the locus is known.
Polymorphic site (PS) - A position within a locus at which at least two alternative sequences are found in a population, the most frequent of which has a frequency of no more than 99%. Polymorphic variant - A gene, mRNA, cDNA, polypeptide or peptide whose nucleotide or amino acid sequence varies from a reference sequence due to the presence of a polymoφhism in the gene.
Polymorphism - The sequence variation observed in an individual at a polymoφhic site. Polymoφhisms include nucleotide substitutions, insertions, deletions and microsatellites and may, but need not, result in detectable differences in gene expression or protein function.
Polymorphism data - Information concerning one or more of the following for a specific gene: location of polymoφhic sites; sequence variation at those sites; frequency of polymoφhisms in one or more populations; the different genotypes and/or haplotypes determined for the gene; frequency of one or more of these genotypes and/or haplotypes in one or more populations; any known association(s) between a trait and a genotype or a haplotype for the gene.
Polymorphism Database - A collection of polymoφhism data arranged in a systematic or methodical way and capable of being individually accessed by electronic or other means.
Polynucleotide - A nucleic acid molecule comprised of single-stranded RNA or DNA or comprised of complementary, double-stranded DNA. Population Group - A group of individuals sharing a common ethnogeographic origin.
Reference Population - A group of subjects or individuals who are predicted to be representative of the genetic variation found in the general population. Typically, the reference population represents the genetic variation in the population at a certainty level of at least 85%, preferably at least 90%, more preferably at least 95% and even more preferably at least 99%. Single Nucleotide Polymorphism (SNP) - Typically, the specific pair of nucleotides observed at a single polymoφhic site. In rare cases, three or four nucleotides may be found.
Subject - A human individual whose genotypes or haplotypes or response to treatment or disease state are to be determined.
Treatment - A stimulus administered internally or externally to a subject. Unphased - As applied to a sequence of nucleotide pairs for two or more polymoφhic sites in a locus, unphased means the combination of nucleotides present at those polymoφhic sites on a single copy of the locus is not known. The inventors herein have discovered 1 novel polymoφhic site in the HTRIE gene. The polymoφhic sites identified by the inventors are referred to as PS 1-2 to designate the order in which they are located in the gene (see Table 3 below), with the novel polymoφhic site referred to as PS1. Thus, in one embodiment, the invention provides an isolated polynucleotide comprising a polymoφhic variant of the HTRIE gene or a fragment of the gene which contains the novel polymoφhic site described herein. The nucleotide sequence of a variant HTRIE gene is identical to the reference genomic sequence for those portions of the gene examined, as described in the Examples below, except that it comprises a different nucleotide at the novel polymoφhic site PS 1 , and may also comprise an additional polymoφhism of thymine at PS2. Similarly, the nucleotide sequence of a variant fragment of the HTRIE gene is identical to the corresponding portion of the reference sequence except for having a different nucleotide at the novel polymoφhic site described herein. Thus, the invention specifically does not include polynucleotides comprising a nucleotide sequence identical to the reference sequence (or other reported HTRIE sequences) or to portions of the reference sequence (or other reported HTRIE sequences), except for genotyping oligonucleotides as described below.
The location of a polymoφhism in a variant gene or fragment is identified by aligning its sequence against SEQ ID NO: 1. The polymoφhism comprises thymine at PS 1. In a preferred embodiment, the polymoφhic variant comprises a naturally-occurring isogene of the HTRIE gene which is defined by any one of haplotypes 1 -3 shown in Table 5 below. Polymoφhic variants of the invention may be prepared by isolating a clone containing the
HTRIE gene from a human genomic library. The clone may be sequenced to determine the identity of the nucleotides at the polymoφhic sites described herein. Any particular variant claimed herein could be prepared from this clone by performing in vitro mutagenesis using procedures well-known in the art. HTRIE isogenes may be isolated using any method that allows separation of the two "copies" of the HTRIE gene present in an individual, which, as readily understood by the skilled artisan, may be the same allele or different alleles. Separation methods include targeted in vivo cloning (TIVC) in yeast as described in WO 98/01573, U.S. Patent No. 5,866,404, and U.S. Patent No. 5,972,614. Another method, which is described in U.S. Patent No. 5,972,614, uses an allele specific oligonucleotide in combination with primer extension and exonuclease degradation to generate hemizygous DNA targets. Yet other methods are single molecule dilution (SMD) as described in Ruaήo et al., Proc. Natl. Acad. Sci. 87:6296-6300, 1990; and allele specific PCR (Ruano et al., 17 Nucleic Acids. Res. 8392, 1989; Ruano et al., 19 Nucleic Acids Res. 6877-6882, 1991; Michalatos- Beloin et al, 24 Nucleic Acids Res. 4841-4843, 1996). The invention also provides HTRIE genome anthologies, which are collections of HTRIE isogenes found in a given population. The population may be any group of at least two individuals, including but not limited to a reference population, a population group, a family population, a clinical population, and a same sex population. A HTRIE genome anthology may comprise individual HTRIE isogenes stored in separate containers such as microtest tubes, separate wells of a microtitre plate and the like. Alternatively, two or more groups of the HTRIE isogenes in the anthology may be stored in separate containers. Individual isogenes or groups of isogenes in a genome anthology may be stored in any convenient and stable form, including but not limited to in buffered solutions, as DNA precipitates, freeze-dried preparations and the like. A preferred HTRIE genome anthology of the invention comprises a set of isogenes defined by the haplotypes shown in Table 5 below.
An isolated polynucleotide containing a polymoφhic variant nucleotide sequence of the invention may be operably linked to one or more expression regulatory elements in a recombinant expression vector capable of being propagated and expressing the encoded HTRIE protein in a prokaryotic or a eukaryotic host cell. Examples of expression regulatory elements which may be used include, but are not limited to, the lac system, operator and promoter regions of phage lambda, yeast promoters, and promoters derived from vaccinia virus, adenovirus, retroviruses, or SV40. Other regulatory elements include, but are not limited to, appropriate leader sequences, termination codons, polyadenylation signals, and other sequences required for the appropriate transcription and subsequent translation of the nucleic acid sequence in a given host cell. Of course, the correct combinations of expression regulatory elements will depend on the host system used. In addition, it is understood that the expression vector contains any additional elements necessary for its transfer to and subsequent replication in the host cell. Examples of such elements include, but are not limited to, origins of replication and selectable markers. Such expression vectors are commercially available or are readily constructed using methods known to those in the art (e.g., F. Ausubel et al., 1987, in "Current Protocols in Molecular Biology", John Wiley and Sons, New York, New York). Host cells which may be used to express the variant HTRIE sequences of the invention include, but are not limited to, eukaryotic and mammalian cells, such as animal, plant, insect and yeast cells, and prokaryotic cells, such as E. coli, or algal cells as known in the art. The recombinant expression vector may be introduced into the host cell using any method known to those in the art including, but not limited to, microinjection, electroporation, particle bombardment, transduction, and transfection using DEAE- dextran, lipofection, or calcium phosphate (see e.g., Sambrook et al. (1989) in "Molecular Cloning. A Laboratory Manual", Cold Spring Harbor Press, Plainview, New York). In a preferred aspect, eukaryotic expression vectors that function in eukaryotic cells, and preferably mammalian cells, are used. Non- limiting examples of such vectors include vaccinia virus vectors, adenovirus vectors, heφes virus vectors, and baculovirus transfer vectors. Preferred eukaryotic cell lines include COS cells, CHO cells, HeLa cells, NIH/3T3 cells, and embryonic stem cells (Thomson, J. A. et al., 1998 Science 282: 1145-1147). Particularly preferred host cells are mammalian cells. As will be readily recognized by the skilled artisan, expression of polymoφhic variants of the
HTRIE gene will produce HTRIE mRNAs varying from each other at any polymoφhic site retained in the spliced and processed mRNA molecules. These mRNAs can be used for the preparation of a HTRIE cDNA comprising a nucleotide sequence which is a polymoφhic variant of the HTRIE reference coding sequence shown in Figure 2. Thus, the invention also provides HTRIE mRNAs and corresponding cDNAs which comprise a nucleotide sequence that is identical to SEQ ID NO:2 (Fig. 2), or its corresponding RNA sequence, except for having a polymoφhism of thymine at a position corresponding to nucleotide 390, and may also comprise an additional polymoφhism of thymine at a position corresponding to nucleotide 531. Fragments of these variant mRNAs and cDNAs are included in the scope of the invention, provided they contain the novel polymoφhism described herein. The invention specifically excludes polynucleotides identical to previously identified and characterized HTRIE cDNAs and fragments thereof. Polynucleotides comprising a variant RNA or DNA sequence may be isolated from a biological sample using well-known molecular biological procedures or may be chemically synthesized.
Polymoφhic variants of fragments according to the invention comprise the novel polymoφhism identified herein and have a length of at least 10 nucleotides and may range up to the full length of the gene. Preferably, such fragments are between 100 and 3000 nucleotides in length, and more preferably between 200 and 2000 nucleotides in length, and most preferably between 500 and 1000 nucleotides in length.
In describing the polymoφhic sites identified herein, reference is made to the sense strand of the gene for convenience. However, as recognized by the skilled artisan, nucleic acid molecules containing the HTRIE gene may be complementary double stranded molecules and thus reference to a particular site on the sense strand refers as well to the corresponding site on the complementary antisense strand. Thus, reference may be made to the same polymoφhic site on either strand and an oligonucleotide may be designed to hybridize specifically to either strand at a target region containing the polymoφhic site. Thus, the invention also includes single-stranded polynucleotides which are complementary to the sense strand of the HTRIE genomic variants described herein. Polynucleotides comprising a polymoφhic gene variant or fragment may be useful for therapeutic puφoses. For example, where a patient could benefit from expression, or increased expression, of a particular HTRIE protein isoform, an expression vector encoding the isoform may be administered to the patient. The patient may be one who lacks the HTRIE isogene encoding that isoform or may already have at least one copy of that isogene. In other situations, it may be desirable to decrease or block expression of a particular HTRIE isogene. Expression of a HTRIE isogene may be turned off by transforming a targeted organ, tissue or cell population with an expression vector that expresses high levels of untranslatable mRNA for the isogene. Alternatively, oligonucleotides directed against the regulatory regions (e.g., promoter, introns, enhancers, 3' untranslated region) of the isogene may block transcription. Oligonucleotides targeting the transcription initiation site, e.g., between positions -10 and +10 from the start site are preferred. Similarly, inhibition of transcription can be achieved using oligonucleotides that base-pair with region(s) of the isogene DNA to form triplex DNA (see e.g., Gee et al. in Huber, B.E. and B.I. Carr, Molecular and Immunologic Approaches, Futura Publishing Co., Mt. Kisco, N.Y., 1994). Antisense oligonucleotides may also be designed to block translation of HTRIE mRNA transcribed from a particular isogene. It is also contemplated that ribozymes may be designed that can catalyze the specific cleavage of HTRIE mRNA transcribed from a particular isogene. The oligonucleotides may be delivered to a target cell or tissue by expression from a vector introduced into the cell or tissue in vivo or ex vivo. Alternatively, the oligonucleotides may be formulated as a pharmaceutical composition for administration to the patient. Oligoribonucleotides and/or oligodeoxynucleotides intended for use as antisense oligonucleotides may be modified to increase stability and half-life. Possible modifications include, but are not limited to phosphorothioate or 2' O-methyl linkages, and the inclusion of nontraditional bases such as inosine and queosine, as well as acetyl-, methyl-, thio-, and similarly modified forms of adenine, cytosine, guanine, thymine, and uracil which are not as easily recognized by endogenous nucleases.
Effect(s) of the polymoφhisms identified herein on expression of HTRIE may be investigated by preparing recombinant cells and/or nonhuman recombinant organisms, preferably recombinant animals, containing a polymoφhic variant of the HTRIE gene. As used herein, "expression" includes but is not limited to one or more of the following: transcription of the gene into precursor mRNA; splicing and other processing of the precursor mRNA to produce mature mRNA; mRNA stability; translation of the mature mRNA into HTRIE protein (including codon usage and tRNA availability); and glycosylation and/or other modifications of the translation product, if required for proper expression and function.
To prepare a recombinant cell of the invention, the desired HTRIE isogene may be introduced into the cell in a vector such that the isogene remains extrachromosomal. In such a situation, the gene will be expressed by the cell from the extrachromosomal location. In a preferred embodiment, the HTRIE isogene is introduced into a cell in such a way that it recombines with the endogenous HTRIE gene present in the cell. Such recombination requires the occurrence of a double recombination event, thereby resulting in the desired HTRIE gene polymoφhism. Vectors for the introduction of genes both for recombination and for extrachromosomal maintenance are known in the art, and any suitable vector or vector construct may be used in the invention. Methods such as electroporation, particle bombardment, calcium phosphate co-precipitation and viral transduction for introducing DNA into cells are known in the art; therefore, the choice of method may lie with the competence and preference of the skilled practitioner. Examples of cells into which the HTRIE isogene may be introduced include, but are not limited to, continuous culture cells, such as COS, NIH/3T3, and primary or culture cells of the relevant tissue type, i.e., they express the HTRIE isogene. Such recombinant cells can be used to compare the biological activities of the different protein variants. Recombinant nonhuman organisms, i.e., transgenic animals, expressing a variant HTRIE gene are prepared using standard procedures known in the art. Preferably, a construct comprising the variant gene is introduced into a nonhuman animal or an ancestor of the animal at an embryonic stage, i.e., the one-cell stage, or generally not later than about the eight-cell stage. Transgenic animals carrying the constructs of the invention can be made by several methods known to those having skill in the art. One method involves transfecting into the embryo a retrovirus constructed to contain one or more insulator elements, a gene or genes of interest, and other components known to those skilled in the art to provide a complete shuttle vector harboring the insulated gene(s) as a transgene, see e.g., U.S. Patent No. 5,610,053. Another method involves directly injecting a transgene into the embryo. A third method involves the use of embryonic stem cells. Examples of animals into which the HTRIE isogenes may be introduced include, but are not limited to, mice, rats, other rodents, and nonhuman primates (see "The Introduction of Foreign Genes into Mice" and the cited references therein, In: Recombinant DNA, Eds. J.D. Watson, M. Gilman, J. Witkowski, and M. Zoller; W.H. Freeman and Company, New York, pages 254-272). Transgenic animals stably expressing a human HTRIE isogene and producing human HTRIE protein can be used as biological models for studying diseases related to abnormal HTRIE expression and/or activity, and for screening and assaying various candidate drugs, compounds, and treatment regimens to reduce the symptoms or effects of these diseases.
An additional embodiment of the invention relates to pharmaceutical compositions for treating disorders affected by expression or function of a novel HTRIE isogene described herein. The pharmaceutical composition may comprise any of the following active ingredients: a polynucleotide comprising one of these novel HTRIE isogenes; an antisense oligonucleotide directed against one of the novel HTRIE isogenes, a polynucleotide encoding such an antisense oligonucleotide, or another compound which inhibits expression of a novel HTRIE isogene described herein. Preferably, the composition contains the active ingredient in a therapeutically effective amount. By therapeutically effective amount is meant that one or more of the symptoms relating to disorders affected by expression or function of a novel HTRIE isogene is reduced and/or eliminated. The composition also comprises a pharmaceutically acceptable carrier, examples of which include, but are not limited to, saline, buffered saline, dextrose, and water. Those skilled in the art may employ a formulation most suitable for the active ingredient, whether it is a polynucleotide, oligonucleotide, protein, peptide or small molecule antagonist. The pharmaceutical composition may be administered alone or in combination with at least one other agent, such as a stabilizing compound. Administration of the pharmaceutical composition may be by any number of routes including, but not limited to oral, intravenous, intramuscular, intra-arterial, intramedullary, intrathecal, intraventricular, intradermal, transdermal, subcutaneous, intraperitoneal, intranasal, enteral, topical, sublingual, or rectal. Further details on techniques for formulation and administration may be found in the latest edition of Remington's Pharmaceutical Sciences (Maack Publishing Co., Easton, PA). For any composition, determination of the therapeutically effective dose of active ingredient and/or the appropriate route of administration is well within the capability of those skilled in the art.
For example, the dose can be estimated initially either in cell culture assays or in animal models. The animal model may also be used to determine the appropriate concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in humans. The exact dosage will be determined by the practitioner, in light of factors relating to the patient requiring treatment, including but not limited to severity of the disease state, general health, age, weight and gender of the patient, diet, time and frequency of administration, other drugs being taken by the patient, and tolerance/response to the treatment.
Information on the identity of genotypes and haplotypes for the HTRIE gene of any particular individual as well as the frequency of such genotypes and haplotypes in any particular population of individuals is expected to be useful for a variety of basic research and clinical applications. Thus, the invention also provides compositions and methods for detecting the novel HTRIE polymoφhisms identified herein.
The compositions comprise at least one HTRIE genotyping oligonucleotide. In one embodiment, a HTRIE genotyping oligonucleotide is a probe or primer capable of hybridizing to a target region that is located close to, or that contains, the novel polymoφhic site described herein. As used herein, the term "oligonucleotide" refers to a polynucleotide molecule having less than about 100 nucleotides. A preferred oligonucleotide of the invention is 10 to 35 nucleotides long. More preferably, the oligonucleotide is between 15 and 30, and most preferably, between 20 and 25 nucleotides in length. The oligonucleotide may be comprised of any phosphorylation state of ribonucleotides, deoxyribonucleotides, and acyclic nucleotide derivatives, and other functionally equivalent derivatives. Alternatively, oligonucleotides may have a phosphate-free backbone, which may be comprised of linkages such as carboxymefhyl, acetamidate, carbamate, polyamide (peptide nucleic acid (PNA)) and the like (Varma, R. in Molecular Biology and Biotechnology, A Comprehensive Desk Reference, Ed. R. Meyers, VCH Publishers, Inc. (1995), pages 617-620). Oligonucleotides of the invention may be prepared by chemical synthesis using any suitable methodology known in the art, or may be derived from a biological sample, for example, by restriction digestion. The oligonucleotides may be labeled, according to any technique known in the art, including use of radiolabels, fluorescent labels, enzymatic labels, proteins, haptens, antibodies, sequence tags and the like.
Genotyping oligonucleotides of the invention must be capable of specifically hybridizing to a target region of a HTRIE polynucleotide, i.e., a HTRIE isogene. As used herein, specific hybridization means the oligonucleotide forms an anti-parallel double-stranded structure with the target region under certain hybridizing conditions, while failing to form such a structure when incubated with a non-target region or a non-HTRlE polynucleotide under the same hybridizing conditions. Preferably, the oligonucleotide specifically hybridizes to the target region under conventional high stringency conditions. The skilled artisan can readily design and test oligonucleotide probes and primers suitable for detecting polymoφhisms in the HTRIE gene using the polymoφhism information provided herein in conjunction with the known sequence information for the HTRIE gene and routine techniques.
A nucleic acid molecule such as an oligonucleotide or polynucleotide is said to be a "perfect" or "complete" complement of another nucleic acid molecule if every nucleotide of one of the molecules is complementary to the nucleotide at the corresponding position of the other molecule. A nucleic acid molecule is "substantially complementary" to another molecule if it hybridizes to that molecule with sufficient stability to remain in a duplex form under conventional low-stringency conditions. Conventional hybridization conditions are described, for example, by Sambrook J. et al., in Molecular Cloning, A Laboratory Manual, 2nd Edition, Cold Spring Harbor Press, Cold Spring Harbor, NY (1989) and by Haymes, B.D. et al. in Nucleic Acid Hybridization, A Practical Approach, IRL Press, Washington, D.C. (1985). While perfectly complementary oligonucleotides are preferred for detecting polymoφhisms, departures from complete complementarity are contemplated where such departures do not prevent the molecule from specifically hybridizing to the target region. For example, an oligonucleotide primer may have a non-complementary fragment at its 5 ' end, with the remainder of the primer being complementary to the target region. Alternatively, non-complementary nucleotides may be interspersed into the oligonucleotide probe or primer as long as the resulting probe or primer is still capable of specifically hybridizing to the target region.
Preferred genotyping oligonucleotides of the invention are allele-specific oligonucleotides. As used herein, the term allele-specific oligonucleotide (ASO) means an oligonucleotide that is able, under sufficiently stringent conditions, to hybridize specifically to one allele of a gene, or other locus, at a target region containing a polymoφhic site while not hybridizing to the corresponding region in another allele(s). As understood by the skilled artisan, allele-specificity will depend upon a variety of readily optimized stringency conditions, including salt and formamide concentrations, as well as temperatures for both the hybridization and washing steps. Examples of hybridization and washing conditions typically used for ASO probes are found in Kogan et al., "Genetic Prediction of Hemophilia A" in PCR Protocols, A Guide to Methods and Applications, Academic Press, 1990 and Ruano et al., 87 Proc. Natl. Acad. Sci. USA 6296-6300, 1990. Typically, an allele-specific oligonucleotide will be perfectly complementary to one allele while containing a single mismatch for another allele.
Allele-specific oligonucleotide probes which usually provide good discrimination between different alleles are those in which a central position of the oligonucleotide probe aligns with the polymoφhic site in the target region (e.g., approximately the 7th or 8th position in a 15 mer, the 8th or
9' position in a 16mer, the 10th or 11th position in a 20 mer). A preferred ASO probe for detecting
HTRIE gene polymoφhisms comprises a nucleotide sequence, listed 5' to 3', selected from the group consisting of:
TTGAATACGCCAGGA (SEQ ID NO : 4 ) and its complement, and TTGAATATGCCAGGA (SEQ ID NO: 5) and its complement.
An allele-specific oligonucleotide primer of the invention has a 3' terminal nucleotide, or preferably a 3' penultimate nucleotide, that is complementary to only one nucleotide of a particular SNP, thereby acting as a primer for polymerase-mediated extension only if the allele containing that nucleotide is present. Allele-specific oligonucleotide primers hybridizing to either the coding or noncoding strand are contemplated by the invention. A preferred ASO primer for detecting HTRIE gene polymoφhisms comprises a nucleotide sequence, listed 5 ' to 3', selected from the group consisting of:
ATGCTATTGAATACG (SEQ ID NO:6); TCCTCTTCCTGGCGT (SEQ ID NO:7); ATGCTATTGAATATG (SEQ ID NO : 8 ) ; and TCCTCTTCCTGGCAT (SEQ ID NO:9).
Other genotyping oligonucleotides of the invention hybridize to a target region located one to several nucleotides downstream of one of the novel polymoφhic sites identified herein. Such oligonucleotides are useful in polymerase-mediated primer extension methods for detecting one of the novel polymoφhisms described herein and therefore such genotyping oligonucleotides are referred to herein as "primer-extension oligonucleotides". In a preferred embodiment, the 3 '-terminus of a primer-extension oligonucleotide is a deoxynucleotide complementary to the nucleotide located immediately adjacent to the polymoφhic site. A particularly preferred oligonucleotide primer for detecting HTRIE gene polymoφhisms by primer extension terminates in a nucleotide sequence, listed 5 ' to 3 ', selected from the group consisting of:
CTATTGAATA (SEQ ID NO:10); and TCTTCCTGGC (SEQ ID NO:ll).
In some embodiments, a composition contains two or more differently labeled genotyping oligonucleotides for simultaneously probing the identity of nucleotides at two or more polymoφhic sites. It is also contemplated that primer compositions may contain two or more sets of allele-specific primer pairs to allow simultaneous targeting and amplification of two or more regions containing a polymoφhic site. HTRIE genotyping oligonucleotides of the invention may also be immobilized on or synthesized on a solid surface such as a microchip, bead, or glass slide (see, e.g., WO 98/20020 and WO 98/20019). Such immobilized genotyping oligonucleotides may be used in a variety of polymoφhism detection assays, including but not limited to probe hybridization and polymerase extension assays. Immobilized HTRIE genotyping oligonucleotides of the invention may comprise an ordered array of oligonucleotides designed to rapidly screen a DNA sample for polymoφhisms in multiple genes at the same time.
In another embodiment, the invention provides a kit comprising at least two genotyping oligonucleotides packaged in separate containers. The kit may also contain other components such as hybridization buffer (where the oligonucleotides are to be used as a probe) packaged in a separate container. Alternatively, where the oligonucleotides are to be used to amplify a target region, the kit may contain, packaged in separate containers, a polymerase and a reaction buffer optimized for primer extension mediated by the polymerase, such as PCR.
The above described oligonucleotide compositions and kits are useful in methods for genotyping and/or haplotyping the HTRIE gene in an individual. As used herein, the terms "HTRIE genotype" and "HTRIE haplotype" mean the genotype or haplotype contains the nucleotide pair or nucleotide, respectively, that is present at the novel polymoφhic site described herein and may optionally also include the nucleotide pair or nucleotide present at one or more additional polymoφhic sites in the HTRIE gene. The additional polymoφhic sites may be currently known polymoφhic sites or sites that are subsequently discovered. One embodiment of the genotyping method involves isolating from the individual a nucleic acid mixture comprising the two copies of the HTRIE gene, or a fragment thereof, that are present in the individual, and determining the identity of the nucleotide pair at PS1 in the two copies to assign a HTRIE genotype to the individual. As will be readily understood by the skilled artisan, the two "copies" of a gene in an individual may be the same allele or may be different alleles. In a preferred embodiment of the genotyping method, the identity of the nucleotide pair at PS2 is also determined. In a particularly preferred embodiment, the genotyping method comprises determining the identity of the nucleotide pair at each of PS1 and PS2.
Typically, the nucleic acid mixture is isolated from a biological sample taken from the individual, such as a blood sample or tissue sample. Suitable tissue samples include whole blood, semen, saliva, tears, urine, fecal material, sweat, buccal, skin and hair. The nucleic acid mixture may be comprised of genomic DNA, mRNA, or cDNA and, in the latter two cases, the biological sample must be obtained from an organ in which the HTRIE gene is expressed. Furthermore it will be understood by the skilled artisan that mRNA or cDNA preparations would not be used to detect polymoφhisms iocated in introns or in 5 ' and 3' nontranscribed regions. If a HTRIE gene fragment is isolated, it must contain the polymoφhic site(s) to be genotyped.
One embodiment of the haplotyping method comprises isolating from the individual a nucleic acid molecule containing only one of the two copies of the HTRIE gene, or a fragment thereof, that is present in the individual and determining in that copy the identity of the nucleotide at PS1 in that copy to assign a HTRIE haplotype to the individual. The nucleic acid may be isolated using any method capable of separating the two copies of the HTRIE gene or fragment such as one of the methods described above for preparing HTRIE isogenes, with targeted in vivo cloning being the preferred approach. As will be readily appreciated by those skilled in the art, any individual clone will only provide haplotype information on one of the two HTRIE gene copies present in an individual. If haplotype information is desired for the individual's other copy, additional HTRIE clones will need to be examined. Typically, at least five clones should be examined to have more than a 90% probability of haplotyping both copies of the HTRIE gene in an individual. In some embodiments, the haplotyping method also comprises identifying the nucleotide at PS2. In a particularly preferred embodiment, the nucleotide at each of PS1 and PS2 is identified.
In a preferred embodiment, a HTRIE haplotype pair is determined for an individual by identifying the phased sequence of nucleotides at each of PS1 and PS2 in each copy of the HTRIE gene that is present in the individual. When haplotyping both copies of the gene, the identifying step is preferably performed with each copy of the gene being placed in separate containers. However, it is also envisioned that if the two copies are labeled with different tags, or are otherwise separately distinguishable or identifiable, it could be possible in some cases to perform the method in the same container. For example, if first and second copies of the gene are labeled with different first and second fluorescent dyes, respectively, and an allele-specific oligonucleotide labeled with yet a third different fluorescent dye is used to assay the polymoφhic site(s), then detecting a combination of the first and third dyes would identify the polymoφhism in the first gene copy while detecting a combination of the second and third dyes would identify the polymoφhism in the second gene copy. In both the genotyping and haplotyping methods, the identity of a nucleotide (or nucleotide pair) at a polymoφhic site(s) may be determined by amplifying a target region(s) containing the polymoφhic site(s) directly from one or both copies of the HTRIE gene, or fragment thereof, and the sequence of the amplified region(s) determined by conventional methods. It will be readily appreciated by the skilled artisan that only one nucleotide will be detected at a polymoφhic site in individuals who are homozygous at that site, while two different nucleotides will be detected if the individual is heterozygous for that site. The polymoφhism may be identified directly, known as positive-type identification, or by inference, referred to as negative-type identification. For example, where a SNP is known to be guanine and cytosine in a reference population, a site may be positively determined to be either guanine or cytosine for an individual homozygous at that site, or both guanine and cytosine, if the individual is heterozygous at that site. Alternatively, the site may be negatively determined to be not guanine (and thus cytosine/cytosine) or not cytosine (and thus guanine/guanine). In addition, the identity of the allele(s) present at any of the polymoφhic sites described herein may be indirectly determined by genotyping a polymoφhic site not disclosed herein that is in linkage disequilibrium with the polymoφhic site that is of interest. Two sites are said to be in linkage disequilibrium if the presence of a particular variant at one site enhances the predictability of another variant at the second site (Stevens, JC 1999, Mol. Diag. 4: 309-17). Polymoφhic sites in linkage disequilibrium with the presently disclosed polymoφhic sites may be located in regions of the gene or in other genomic regions not examined herein. Genotyping of a polymoφhic site in linkage disequilibrium with the novel polymoφhic sites described herein may be performed by, but is not limited to, any of the above-mentioned methods for detecting the identity of the allele at a polymoφhic site. The target region(s) may be amplified using any oligonucleotide-directed amplification method, including but not limited to polymerase chain reaction (PCR) (U.S. Patent No. 4,965,188), ligase chain reaction (LCR) (Barany et al., Proc. Natl. Acad. Sci. USA 88: 189-193, 1991; WO90/01069), and oligonucleotide ligation assay (OLA) (Landegren et al, Science 241:1077-1080, 1988). Oligonucleotides useful as primers or probes in such methods should specifically hybridize to a region of the nucleic acid that contains or is adjacent to the polymoφhic site. Typically, the oligonucleotides are between 10 and 35 nucleotides in length and preferably, between 15 and 30 nucleotides in length. Most preferably, the oligonucleotides are 20 to 25 nucleotides long. The exact length of the oligonucleotide will depend on many factors that are routinely considered and practiced by the skilled artisan.
Other known nucleic acid amplification procedures may be used to amplify the target region including transcription-based amplification systems (U.S. Patent No. 5,130,238; EP 329,822; U.S. Patent No. 5,169,766, WO89/06700) and isothermal methods (Walker et al., Proc. Natl. Acad. Sci. USA 89:392-396, 1992).
A polymoφhism in the target region may also be assayed before or after amplification using one of several hybridization-based methods known in the art. Typically, allele-specific oligonucleotides are utilized in performing such methods. The allele-specific oligonucleotides may be used as differently labeled probe pairs, with one member of the pair showing a perfect match to one variant of a target sequence and the other member showing a perfect match to a different variant. In some embodiments, more than one polymoφhic site may be detected at once using a set of allele- specific oligonucleotides or oligonucleotide pairs. Preferably, the members of the set have melting temperatures within 5°C, and more preferably within 2°C, of each other when hybridizing to each of the polymoφhic sites being detected.
Hybridization of an allele-specific oligonucleotide to a target polynucleotide may be performed with both entities in solution, or such hybridization may be performed when either the oligonucleotide or the target polynucleotide is covalently or noncovalently affixed to a solid support. Attachment may be mediated, for example, by antibody-antigen interactions, poly-L-Lys, streptavidin or avidin-biotin, salt bridges, hydrophobic interactions, chemical linkages, UV cross-linking baking, etc. Allele-specific oligonucleotides may be synthesized directly on the solid support or attached to the solid support subsequent to synthesis. Solid-supports suitable for use in detection methods of the invention include substrates made of silicon, glass, plastic, paper and the like, which may be formed, for example, into wells (as in 96-well plates), slides, sheets, membranes, fibers, chips, dishes, and beads. The solid support may be treated, coated or derivatized to facilitate the immobilization of the allele-specific oligonucleotide or target nucleic acid.
The genotype or haplotype for the HTRIE gene of an individual may also be determined by hybridization of a nucleic acid sample containing one or both copies of the gene to nucleic acid arrays and subarrays such as described in WO 95/1 1995. The arrays would contain a battery of allele- specific oligonucleotides representing each of the polymoφhic sites to be included in the genotype or haplotype.
The identity of polymoφhisms may also be determined using a mismatch detection technique, including but not limited to the RNase protection method using riboprobes (Winter et al., Proc. Natl. Acad. Sci. USA 82:7575, 1985; Meyers et al., Science 230:1242, 1985) and proteins which recognize nucleotide mismatches, such as the E. coli mutS protein (Modrich, P. Ann. Rev. Genet. 25:229-253, 1991). Alternatively, variant alleles can be identified by single strand conformation polymoφhism (SSCP) analysis (Orita et al., Genomics 5:874-879, 1989; Humphries et al., in Molecular Diagnosis of Genetic Diseases, R. Elles, ed., pp. 321-340, 1996) or denaturing gradient gel electrophoresis (DGGE) (Wartell et al., Nucl. Acids Res. 18:2699-2706, 1990; Sheffield et al, Proc. Natl. Acad. Sci. USA 86:232-236, 1989).
A polymerase-mediated primer extension method may also be used to identify the polymoφhism(s). Several such methods have been described in the patent and scientific literature and include the "Genetic Bit Analysis" method (W092/15712) and the ligase/polymerase mediated genetic bit analysis (U.S. Patent 5,679,524. Related methods are disclosed in WO91/02087, WO90/09455, W095/17676, U.S. Patent Nos. 5,302,509, and 5,945,283. Extended primers containing a polymoφhism may be detected by mass spectrometry as described in U.S. Patent No. 5,605,798. Another primer extension method is allele-specific PCR (Ruano et al., Nucl. Acids Res. 17:8392,
1989; Ruano et al., Nucl. Acids Res. 19, 6877-6882, 1991; WO 93/22456; Turki et al., J. Clin. Invest. 95: 1635-1641, 1995). In addition, multiple polymoφhic sites may be investigated by simultaneously amplifying multiple regions of the nucleic acid using sets of allele-specific primers as described in Wallace et al. (WO89/10414). In another aspect of the invention, an individual's HTRIE haplotype pair is predicted from its
HTRIE genotype using information on haplotype pairs known to exist in a reference population. In its broadest embodiment, the haplotyping prediction method comprises identifying a HTRIE genotype for the individual at PS1 and PS2, enumerating all possible haplotype pairs which are consistent with the genotype, accessing data containing HTRIE haplotype pairs identified in a reference population, and assigning a haplotype pair to the individual that is consistent with the data. In one embodiment, the reference haplotype pairs include the HTRIE haplotype pairs shown in Table 4.
Generally, the reference population should be composed of randomly-selected individuals representing the major ethnogeographic groups of the world. A preferred reference population for use in the methods of the present invention comprises an approximately equal number of individuals from Caucasian, African American, Asian and Hispanic-Latino population groups with the minimum number of each group being chosen based on how rare a haplotype one wants to be guaranteed to see. For example, if one wants to have a q% chance of not missing a haplotype that exists in the population at a p% frequency of occurring in the reference population, the number of individuals (n) who must be sampled is given by 2n=log(l-q)/log(l-p) where p and q are expressed as fractions. A preferred reference population allows the detection of any haplotype whose frequency is at least 10% with about
99% certainty and comprises about 20 unrelated individuals from each of the four population groups named above. A particularly preferred reference population includes a 3-generation family representing one or more of the four population groups to serve as controls for checking quality of haplotyping procedures.
In a preferred embodiment, the haplotype frequency data for each ethnogeographic group is examined to determine whether it is consistent with Hardy- Weinberg equilibrium. Hardy- Weinberg equilibrium (D.L. Haiti et al. Principles of Population Genomics, Sinauer Associates (Sunderland, MA), 3rd Ed, 1997) postulates that the frequency of finding the haplotype pair H, I H2 is equal to pH_w(H H2) = 2p(Hλ)p(H2) if H, ≠ H2 and pH_w(H H2) = p(H, )p(H2) if H, = H2 .
A statistically significant difference between the observed and expected haplotype frequencies could be due to one or more factors including significant inbreeding in the population group, strong selective pressure on the gene, sampling bias, and/or errors in the genotyping process. If large deviations from Hardy- Weinberg equilibrium are observed in an ethnogeographic group, the number of individuals in that group can be increased to see if the deviation is due to a sampling bias. If a larger sample size does not reduce the difference between observed and expected haplotype pair frequencies, then one may wish to consider haplotyping the individual using a direct haplotyping method such as, for example, CLASPER System technology (U.S. Patent No. 5,866,404), SMD, or allele-specific long- range PCR (Michalotos-Beloin et al. Nucleic Acids Res. 24:4841-4843, 1996).
In one embodiment of this method for predicting a HTRIE haplotype pair, the assigning step involves performing the following analysis. First, each of the possible haplotype pairs is compared to the haplotype pairs in the reference population. Generally, only one of the haplotype pairs in the reference population matches a possible haplotype pair and that pair is assigned to the individual. Occasionally, only one haplotype represented in the reference haplotype pairs is consistent with a possible haplotype pair for an individual, and in such cases the individual is assigned a haplotype pair containing this known haplotype and a new haplotype derived by subtracting the known haplotype from the possible haplotype pair. In rare cases, either no haplotypes in the reference population are consistent with the possible haplotype pairs, or alternatively, multiple reference haplotype pairs are consistent with the possible haplotype pairs. In such cases, the individual is preferably haplotyped using a direct molecular haplotyping method such as, for example, CLASPER System technology (U.S. Patent No. 5,866,404), SMD, or allele-specific long-range PCR (Michalotos-Beloin et al. Nucleic Acids Res. 24:4841-4843, 1996). A preferred process for predicting HTRIE haplotype pairs from HTRIE genotypes is described in copending U.S. Provisional Application Serial No. 60/198,340. The invention also provides a method for determining the frequency of a HTRIE genotype or HTRIE haplotype in a population. The method comprises determining the genotype or the haplotype pair for the HTRIE gene that is present in each member of the population, wherein the genotype or haplotype comprises the nucleotide pair or nucleotide detected at PS1 in the HTRIE gene; and calculating the frequency any particular genotype or haplotype is found in the population. The population may be a reference population, a family population, a same sex population, a population group, a trait population (e.g., a group of individuals exhibiting a trait of interest such as a medical condition or response to a therapeutic treatment).
In another aspect of the invention, frequency data for HTRIE genotypes and/or haplotypes found in a reference population are used in a method for identifying an association between a trait and a HTRIE genotype or a HTRIE haplotype. The trait may be any detectable phenotype, including but not limited to susceptibility to a disease or response to a treatment. The method involves obtaining data on the frequency of the genotype(s) or haplotype(s) of interest in a reference population as well as in a population exhibiting the trait. Frequency data for one or both of the reference and trait populations may be obtained by genotyping or haplotyping each individual in the populations using one of the methods described above. The haplotypes for the trait population may be determined directly or, alternatively, by the predictive genotype to haplotype approach described above. In another embodiment, the frequency data for the reference and/or trait populations is obtained by accessing previously determined frequency data, which may be in written or electronic form. For example, the frequency data may be present in a database that is accessible by a computer. Once the frequency data is obtained, the frequencies of the genotype(s) or haplotype(s) of interest in the reference and trait populations are compared. In a preferred embodiment, the frequencies of all genotypes and/or haplotypes observed in the populations are compared. If a particular genotype or haplotype for the HTRIE gene is more frequent in the trait population than in the reference population at a statistically significant amount, then the trait is predicted to be associated with that HTRIE genotype or haplotype. Preferably, the HTRIE genotype or haplotype being compared in the trait and reference populations is selected from the full-genotypes and full-haplotypes shown in Tables 4 and 5, respectively, or from sub-genotypes and sub-haplotypes derived from these genotypes and haplotypes.
In a preferred embodiment of the method, the trait of interest is a clinical response exhibited by a patient to some therapeutic treatment, for example, response to a drug targeting HTRIE or response to a therapeutic treatment for a medical condition. As used herein, "medical condition" includes but is not limited to any condition or disease manifested as one or more physical and/or psychological symptoms for which treatment is desirable, and includes previously and newly identified diseases and other disorders. As used herein the term "clinical response" means any or all of the following: a quantitative measure of the response, no response, and adverse response (i.e., side effects).
In order to deduce a correlation between clinical response to a treatment and a HTRIE genotype or haplotype, it is necessary to obtain data on the clinical responses exhibited by a population of individuals who received the treatment, hereinafter the "clinical population". This clinical data may be obtained by analyzing the results of a clinical trial that has already been run and/or the clinical data may be obtained by designing and carrying out one or more new clinical trials. As used herein, the term "clinical trial" means any research study designed to collect clinical data on responses to a particular treatment, and includes but is not limited to phase I, phase II and phase III clinical trials. Standard methods are used to define the patient population and to enroll subjects.
It is preferred that the individuals included in the clinical population have been graded for the existence of the medical condition of interest. This is important in cases where the symptom(s) being presented by the patients can be caused by more than one underlying condition, and where treatment of the underlying conditions are not the same. An example of this would be where patients experience breathing difficulties that are due to either asthma or respiratory infections. If both sets were treated with an asthma medication, there would be a spurious group of apparent non-responders that did not actually have asthma. These people would affect the ability to detect any correlation between haplotype and treatment outcome. This grading of potential patients could employ a standard physical exam or one or more lab tests. Alternatively, grading of patients could use haplotyping for situations where there is a strong correlation between haplotype pair and disease susceptibility or severity.
The therapeutic treatment of interest is administered to each individual in the trial population and each individual's response to the treatment is measured using one or more predetermined criteria. It is contemplated that in many cases, the trial population will exhibit a range of responses and that the investigator will choose the number of responder groups (e.g., low, medium, high) made up by the various responses. In addition, the HTRIE gene for each individual in the trial population is genotyped and/or haplotyped, which may be done before or after administering the treatment.
After both the clinical and polymoφhism data have been obtained, correlations between individual response and HTRIE genotype or haplotype content are created. Correlations may be produced in several ways. In one method, individuals are grouped by their HTRIE genotype or haplotype (or haplotype pair) (also referred to as a polymoφhism group), and then the averages and standard deviations of clinical responses exhibited by the members of each polymoφhism group are calculated.
These results are then analyzed to determine if any observed variation in clinical response between polymoφhism groups is statistically significant. Statistical analysis methods which may be used are described in L.D. Fisher and G. vanBelle, "Biostatistics: A Methodology for the Health Sciences", Wiley-Interscience (New York) 1993. This analysis may also include a regression calculation of which polymoφhic sites in the HTRIE gene give the most significant contribution to the differences in phenotype. One regression model useful in the invention is described in PCT Application Serial No. PCT USOO/l 7540, entitled "Methods for Obtaining and Using Haplotype Data".
A second method for finding correlations between HTRIE haplotype content and clinical responses uses predictive models based on error-minimizing optimization algorithms. One of many possible optimization algorithms is a genetic algorithm (R. Judson, "Genetic Algorithms and Their Uses in Chemistry" in Reviews in Computational Chemistry, Vol. 10, pp. 1-73, K. B. Lipkowitz and D. B. Boyd, eds. (VCH Publishers, New York, 1997). Simulated annealing (Press et al, "Numerical
Recipes in C: The Art of Scientific Computing", Cambridge University Press (Cambridge) 1992, Ch. 10), neural networks (E. Rich and K. Knight, "Artificial Intelligence", 2nd Edition (McGraw-Hill, New York, 1991, Ch. 18), standard gradient descent methods (Press et al, supra Ch. 10), or other global or local optimization approaches (see discussion in Judson, supra) could also be used. Preferably, the correlation is found using a genetic algorithm approach as described in PCT Application Serial No. PCT USOO/l 7540.
Correlations may also be analyzed using analysis of variation (ANOVA) techniques to determine how much of the variation in the clinical data is explained by different subsets of the polymoφhic sites in the HTRIE gene. As described in PCT Application Serial No. PCT/US00/17540, ANOVA is used to test hypotheses about whether a response variable is caused by or correlated with one or more traits or variables that can be measured (Fisher and vanBelle, supra, Ch. 10).
From the analyses described above, a mathematical model may be readily constructed by the skilled artisan that predicts clinical response as a function of HTRIE genotype or haplotype content.
Preferably, the model is validated in one or more follow-up clinical trials designed to test the model.
The identification of an association between a clinical response and a genotype or haplotype (or haplotype pair) for the HTRIE gene may be the basis for designing a diagnostic method to determine those individuals who will or will not respond to the treatment, or alternatively, will respond at a lower level and thus may require more treatment, i.e., a greater dose of a drug. The diagnostic method may take one of several forms: for example, a direct DNA test (i.e., genotyping or haplotyping one or more of the polymoφhic sites in the HTRIE gene), a serological test, or a physical exam measurement. The only requirement is that there be a good correlation between the diagnostic test results and the underlying HTRIE genotype or haplotype that is in turn correlated with the clinical response. In a preferred embodiment, this diagnostic method uses the predictive haplotyping method described above.
Any or all analytical and mathematical operations involved in practicing the methods of the present invention may be implemented by a computer. In addition, the computer may execute a program that generates views (or screens) displayed on a display device and with which the user can interact to view and analyze large amounts of information relating to the HTRIE gene and its genomic variation, including chromosome location, gene structure, and gene family, gene expression data, polymoφhism data, genetic sequence data, and clinical data population data (e.g., data on ethnogeographic origin, clinical responses, genotypes, and haplotypes for one or more populations). The HTRIE polymoφhism data described herein may be stored as part of a relational database (e.g., an instance of an Oracle database or a set of ASCII flat files). These polymoφhism data may be stored on the computer's hard drive or may, for example, be stored on a CD ROM or on one or more other storage devices accessible by the computer. For example, the data may be stored on one or more databases in communication with the computer via a network.
Preferred embodiments of the invention are described in the following examples. Other embodiments within the scope of the claims herein will be apparent to one skilled in the art from consideration of the specification or practice of the invention as disclosed herein. It is intended that the specification, together with the examples, be considered exemplary only, with the scope and spirit of the invention being indicated by the claims which follow the examples.
EXAMPLES The Examples herein are meant to exemplify the various aspects of carrying out the invention and are not intended to limit the scope of the invention in any way. The Examples do not include detailed descriptions for conventional methods employed, such as in the performance of genomic DNA isolation, PCR and sequencing procedures. Such methods are well-known to those skilled in the art and are described in numerous publications, for example, Sambrook, Fritsch, and Maniatis, "Molecular Cloning: A Laboratory Manual", 2nd Edition, Cold Spring Harbor Laboratory Press, USA, (1989).
EXAMPLE 1 This example illustrates examination of various regions of the HTRIE gene for polymoφhic sites.
Amplification of Target Regions
The following target regions of the HTRIE gene were amplified using the PCR primer pairs listed below, with the sequences presented in the 5 ' to 3 ' direction and nucleotide positions shown for each region corresponding to the indicated GenBank Accession No.
Fragment 1 Forward Primer: 417-440 TCATTTGCATGACTCTGGTGGTC (SEQ ID NO: 12)
Reverse Primer: complement of 891 -861 AGATAACATGGTCGTGCTGGATG (SEQ ID NO: 13) 475 nt PCR product Fragment 2
Forward Primer:
729-751 ATTGAATACGCCAGGAAGAGGAC (SEQ ID NO: 14)
Reverse Primer: complement of 1248-1218 TGAATGCACCCAGAATCAGCC (SEQ ID NO: 15) 520 nt PCR product
Fragment 3 Forward Primer: 1069-1094 TTTCTGTGTGTCTGACTTCTCCACC (SEQ ID NO: 16) Reverse Primer: complement of 1517- 1496 AATAAGTTGCACCCCTTACCCC (SEQ ID NO: 17) 449 nt PCR product Fragment 4 Forward Primer: 1242-1263 GCATTCATTTTATCCTGGCTGC (SEQ ID NO: 18) Reverse Primer: complement of 1644-1623 CCAGAGGTAGAAAACAGCACGC (SEQ ID NO: 19) 403 nt PCR product
These primer pairs were used in PCR reactions containing genomic DNA isolated from immortalized cell lines for each member of the Index Repository. The PCR reactions were carried out under the following conditions:
Reaction volume = 20 μl
10 x Advantage 2 Polymerase reaction buffer (Clontech) = 2 μl
100 ng of human genomic DNA = l μl lO mM dNTP = 0.4 μl
Advantage 2 Polymerase enzyme mix (Clontech) = 0.2 μl
Forward Primer (10 μM) = 0.4 μl
Reverse Primer (10 μM) = 0.4 μl
Water = 15.6μl
Amplification profile: 94°C - 2 min. 1 cycle
94°C - 30 sec. 70°C - 45 sec. 10 cycles 72°C - 1 min.
94°C - 30 sec. 64°C - 45 sec. 35 cycles
72°C - 1 min.
Sequencing of PCR Products
The PCR products were purified by Solid Phase Reversible Immobilization using the protocol developed by the Whitehead Genome Center. A detailed protocol can be found at http://www.genome.wi.mit.edu/sequencing/protocols/pure/SPRI_pcr.html.
Briefly, five μl of carboxyl coated magnetic beads (10 mg/ml) and 60 μl of HYB BUFFER (2.5M NaCl/20% PEG 8000) were added to each PCR reaction mixture (20 μl). The reaction mixture was mixed well and incubated at room temperature (RT) for 10 min. The microtitre plate was placed on a magnet for 2 min and the beads washed twice with 150 μl of 70% EtOH. The beads were air dried for 2 min and the DNA was eluted in 25 μl of distilled water and incubated at RT for 5 min. The beads were magnetically separated and the supernatant removed for testing and sequencing.
The purified PCR products were sequenced in both directions using the primer sets described above. Analysis of Sequences for Polymoφhic Sites
Sequences were analyzed for the presence of polymoφhisms using the Polyphred program (Nickerson et al. Nucleic Acids Res. 14:2745-2751, 1997). The presence of a polymoφhism was confirmed on both strands. The polymoφhisms and their locations in the HTRIE gene are listed in Table 3 below.
Table 3. Polymoφhic Sites Identified in the HTRIE Gene
Polymoφhic Reference Variant
Site Number Nucleotide Position Nucleotide Position Allele Allele PS1 737(Acc#Zl 1166.1) 956(Acc#M91467.1) C T
PS2R 878(Acc#Zl 1166.1) 1097(Acc#M91467.1) C T
R reported previously in literature
Polymoφhic sites PS1 and PS2 have previously been mapped to nucleotide positions 956 and 1097 respectively, corresponding to GenBank Accession No. M91467.1 in the U.S. Provisional Application Number 60/160,280 filed on October 19, 1999.
EXAMPLE 2 This example illustrates analysis of the HTRIE polymoφhisms identified in the Index Repository for human genotypes and haplotypes.
The different genotypes containing these polymoφhisms that were observed in the reference population are shown in Table 4 below, with the haplotype pair indicating the combination of haplotypes determined for the individual using the haplotype derivation protocol described below. In Table 4, homozygous positions are indicated by one nucleotide and heterozygous positions are indicated by two nucleotides. Missing nucleotides in any given genotype in Table 4 were inferred based on linkage disequilibrium and/or Mendelian inheritance.
Table 4. Genotypes and Haplotype Pairs Observed for HTRIE Gene Genotype Polymorphic Sites Number PS1 PS2 HAP Pair
1 C C 1 1
2 C/T C 1 3
3 C C/T 1 2
The haplotype pairs shown in Table 4 were estimated from the unphased genotypes using an extension of Clark's algorithm (Clark, A.G. (1990) Mol Bio Evol 7, 1 11-122), as described in U.S. Provisional Application Serial No. 60/198,340 entitled "A Method and System for Determining Haplotypes from a Collection of Polymoφhisms". In this method, haplotypes are assigned directly from individuals who are homozygous at all sites or heterozygous at no more than one of the variable sites. In our analysis, the list of haplotypes is augmented with haplotypes obtained from a three- generation Caucasian family and a two-generation African- American family. This list of haplotypes is then used to deconvolute the unphased genotypes in the remaining (multiply heterozygous) individuals.
By following this protocol, it was determined that the Index Repository examined herein and, by extension, the general population contains the 3 human HTRIE haplotypes shown in Table 5 below.
Table 5. Haplotypes Identified in the HTRIE Gene
Haplotype Poly orphic Sites
PS PS
Number 1 2
1 c C
2 c T
3 T C
In view of the above, it will be seen that the several advantages of the invention are achieved and other advantageous results attained.
As various changes could be made in the above methods and compositions without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be inteφreted as illustrative and not in a limiting sense.
All references cited in this specification, including patents and patent applications, are hereby incoφorated in their entirety by reference. The discussion of references herein is intended merely to summarize the assertions made by their authors and no admission is made that any reference constitutes prior art. Applicants reserve the right to challenge the accuracy and pertinency of the cited references.

Claims

What is Claimed is:
1. An isolated polynucleotide comprising a nucleotide sequence selected from the group consisting of:
(a) a first nucleotide sequence which is a polymoφhic variant of a reference sequence for 5- hydroxytryptamine (serotonin) receptor IE (HTRIE) gene or a fragment thereof, wherein the reference sequence comprises SEQ ID NO: 1, and the polymoφhic variant comprises thymine at polymoφhic site PS1; and
(b) a second nucleotide sequence which is complementary to the first nucleotide sequence.
2. The isolated polynucleotide of claim 1 which comprises a HTRIE isogene.
3. The isolated polynucleotide of claim 1 which is a DNA molecule and comprises both the first and second nucleotide sequences and further comprises expression regulatory elements operably linked to the first nucleotide sequence.
4. A recombinant nonhuman organism transformed or transfected with the isolated polynucleotide of claim 1, wherein the organism expresses a HTRIE protein encoded by the first nucleotide sequence.
5. The recombinant organism of claim 4 which is a nonhuman transgenic animal.
6. The isolated polynucleotide of claim 1, wherein the first nucleotide sequence is a polymoφhic variant of a fragment of the HTRIE gene, the fragment comprising thymine at PS1.
7. An isolated polynucleotide comprising a nucleotide sequence which is a polymoφhic variant of a reference sequence for the HTRIE cDNA or a fragment thereof, wherein the reference sequence comprises SEQ ID NO:2 and the polymoφhic variant comprises thymine at a position corresponding to nucleotide 390 .
8. A recombinant organism transformed or transfected with the isolated polynucleotide of claim 7, wherein the organism expresses a 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) protein encoded by the polymoφhic variant sequence.
9. The recombinant nonhuman organism of claim 8 which is a nonhuman transgenic animal.
10. A composition comprising at least one genotyping oligonucleotide for detecting a polymoφhism in the 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) gene at PS1.
11. The composition of claim 10, wherein the genotyping oligonucleotide is an allele-specific oligonucleotide that specifically hybridizes to an allele of the HTRIE gene at a region containing PS1.
12. The composition of claim 11, wherein the allele-specific oligonucleotide comprises a nucleotide sequence selected from the group consisting of of SEQ ID NOS:4-5, the complements of SEQ ID NOS: 4-5, and SEQ ID NOS:6-9.
13. The composition of claim 10, wherein the genotyping oligonucleotide is a primer-extension oligonucleotide.
14. A method for genotyping the 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) gene of an individual, comprising determining for the two copies of the HTRIE gene present in the individual the identity of the nucleotide pair at PS1.
15. The method of claim 14, wherein the determining step comprises:
(a) isolating from the individual a nucleic acid mixture comprising both copies of the HTRIE gene, or a fragment thereof, that are present in the individual;
(b) amplifying from the nucleic acid mixture a target region containing at least PS 1 ; (c) hybridizing a primer extension oligonucleotide to one allele of the amplified target region;
(d) performing a nucleic acid template-dependent, primer extension reaction on the hybridized genotyping oligonucleotide in the presence of at least two different terminators of the reaction, wherein said terminators are complementary to the alternative nucleotides present at the polymoφhic site; and (e) detecting the presence and identity of the terminator in the extended genotyping oligonucleotide.
16. A method for haplotyping the 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) gene of an individual which comprises determining, for one copy of the HTRIE gene present in the individual, the identity of the nucleotide at PS 1.
17. The method of claim 16, wherein the determining step comprises
(a) isolating from the individual a nucleic acid molecule containing only one of the two copies of the HTRIE gene, or a fragment thereof, that is present in the individual;
(b) amplifying from the nucleic acid molecule a target region containing at least PS1 ; (c) hybridizing a primer extension oligonucleotide to one allele of the amplified target region;
(d) performing a nucleic acid template-dependent, primer extension reaction on the hybridized genotyping oligonucleotide in the presence of at least two different terminators of the reaction, wherein said terminators are complementary to the alternative nucleotides present at the polymoφhic site; and (e) detecting the presence and identity of the terminator in the extended genotyping oligonucleotide.
18. A method for predicting a haplotype pair for the 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) gene of an individual comprising:
(a) identifying an HTRIE genotype for the individual at PS1 and PS2;
(b) enumerating all possible haplotype pairs which are consistent with the genotype; (c) accessing data containing the HTRIE haplotype pairs determined in a reference population; and (d) assigning a haplotype pair to the individual that is consistent with the data.
19. A method for identifying an association between a trait and at least one genotype or haplotype of the 5-hydroxytryptamine (serotonin) receptor IE gene which comprises comparing the frequency of the genotype or haplotype in a population exhibiting the trait with the frequency of the genotype or haplotype in a reference population, wherein the genotype or haplotype comprises a nucleotide pair or nucleotide located at PS 1 , wherein a higher frequency of the genotype or haplotype in the trait population than in the reference population indicates the trait is associated with the genotype or haplotype.
20 The method of claim 19, wherein the haplotype is selected from haplotype numbers 1-3 shown in Table 5.
21. The method of claim 20, wherein the trait is a clinical response to a drug targeting HTRIE .
22. A computer system for storing and analyzing polymoφhism data for the 5-hydroxytryptamine (serotonin) receptor IE gene, comprising:
(a) a central processing unit (CPU); (b) a communication interface;
(c) a display device;
(d) an input device; and
(e) a database containing the polymoφhism data; wherein the polymoφhism data comprises the genotypes and haplotype pairs shown in Table 4 and the haplotypes shown in Table 5.
23. A genome anthology for the 5-hydroxytryptamine (serotonin) receptor IE (HTRIE) gene which comprises HTRIE isogenes defined by haplotypes 1-3 shown in Table 5.
PCT/US2000/028584 1999-10-19 2000-10-16 Drug target isogenes: polymorphisms in the 5-hydroxytryptamine (serotonin) receptor 1e gene WO2001029263A1 (en)

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