Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/74—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving hormones or other non-cytokine intercellular protein regulatory factors such as growth factors, including receptors to hormones and growth factors
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
  • C07K14/705—Receptors; Cell surface antigens; Cell surface determinants
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K38/00—Medicinal preparations containing peptides
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K48/00—Medicinal preparations containing genetic material which is inserted into cells of the living body to treat genetic diseases; Gene therapy
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2333/00—Assays involving biological materials from specific organisms or of a specific nature
  • G01N2333/435—Assays involving biological materials from specific organisms or of a specific nature from animals; from humans
  • G01N2333/705—Assays involving receptors, cell surface antigens or cell surface determinants
  • G01N2333/72—Assays involving receptors, cell surface antigens or cell surface determinants for hormones
  • G01N2333/726—G protein coupled receptor, e.g. TSHR-thyrotropin-receptor, LH/hCG receptor, FSH

Definitions

• the invention relates to the area of G protein-coupled receptors. More particularly, it relates to the area of human RTA-like G protein-coupled receptors and their regulation for therapeutic purposes.
• GPCR G-protein coupled receptors
• GPCRs include receptors for such diverse agents as dopamine, calcitonin, adrenergic hormones, endothelin, cAMP, adenosine, acetylcholine, serotonin, histamine, thrombin, kinin, follicle stimulating hormone, opsins, endothelial differentiation gene-1, rhodopsins, odorants, cytomegalovirus, G-proteins themselves, effector proteins such as phospholipase C, adenyl cyclase, and phosphodiesterase, and actuator proteins such as protein kinase A and protein kinase C.
• GPCRs possess seven conserved membrane-spanning domains connecting at least eight divergent hydrophilic loops. GPCRs (also known as 7TM receptors) have been characterized as including these seven conserved hydrophobic stretches of about 20 to 30 amino acids, connecting at least eight divergent hydrophilic loops. Most GPCRs have single conserved cysteine residues in each of the first two extracellular loops, which form disulfide bonds that are believed to stabilize functional protein structure. The seven transmembrane regions are designated as TM1, TM2, TM3, TM4, TM5, TM6, and TM7. TM3 has been implicated in signal transduction.
• Phosphorylation and lipidation (palmitylation or farnesylation) of cysteine residues can influence signal transduction of some GPCRs.
• Most GPCRs contain potential phosphorylation sites within the third cytoplasmic loop and/or the carboxy terminus.
• GPCRs such as the ⁇ -adrenergic receptor, phosphorylation by protein kinase A and/or specific receptor kinases mediates receptor desensitization.
• the ligand binding sites" ⁇ of GPCRs are believed to comprise hydrophilic sockets formed by several GPCR transmembrane domains.
• the hydrophilic sockets are surrounded by hydrophobic residues of the GPCRs.
• the hydrophilic side of each GPCR transmembrane helix is postulated to face inward and form a polar ligand binding site.
• TM3 has been implicated in several GPCRs as having a ligand binding site, such as the TM3 aspartate residue.
• TM5 serines, a TM6 asparagine, and TM6 or TM7 phenylalanines or tyrosines also are implicated in ligand binding.
• GPCRs are coupled inside the cell by heterotrimeric G-proteins to various intracellular enzymes, ion channels, and transporters (see Johnson et al, Endoc. Rev.
• G-protein alpha-subunits preferentially stimulate particular effectors to modulate , various biological functions in a cell.
• Phosphorylation of cytoplasmic residues of GPCRs is an important mechanism for the regulation of some GPCRs.
• the effect of hormone binding is the activation inside the cell of the enzyme, adenylate cyclase.
• Enzyme activation by hormones is dependent on the presence of the nucleotide GTP.
• GTP also influences hormone binding.
• a G-protein connects the hormone receptor to adenylate cyclase.
• G-protein exchanges GTP for bound GDP when activated by a hormone receptor.
• the GTP-carrying form then binds to activated adenylate cyclase.
• the G-protein serves a dual role, as an intermediate that relays the signal from receptor to effector, and as a clock that controls the duration of the signal.
• GPCRs receptors Over the past 15 years, nearly 350 therapeutic agents targeting GPCRs receptors have been successfully introduced onto the market. This indicates that these receptors have an established, proven history as therapeutic targets. Clearly, there is an ongoing need for identification and characterization of further GPCRs which can play a role in preventing, ameliorating, or correcting dysfunctions or diseases including, but not limited to, infections such as bacterial, fungal, protozoan, and viral infections, particularly those caused by HIN viruses, pain, cancers, anorexia, bulimia, asthma,
• Parkinson's diseases acute heart failure, hypotension, - hypertension, urinary retention, osteoporosis, angina pectoris, myocardial infarction, ulcers, asthma, allergies, benign prostatic hypertrophy, and psychotic and neurological disorders, including anxiety, schizophrenia, manic depression, delirium, dementia, several mental retardation, and dyskinesias, such as Huntington's disease and Tourett's syndrome.
• RTA-like G protein-coupled receptor RTA-like-GPCR
• RTA-like-GPCR polypeptide comprising an amino acid sequence selected from the group consisting of: amino acid sequences which are at least about 50% identical to the amino acid sequence shown in SEQ ID NO: 2; and
• Yet another embodiment of the invention is a method of screening for agents which decrease the activity of RTA-like-GPCR.
• a test compound is contacted with a RTA- like-GPCR polypeptide comprising an amino acid sequence selected from the group consisting of:
• amino acid sequences which are at least about 50% identical to the amino acid sequence shown in SEQ ID NO: 2;
• Binding between the test compound and the RTA-like-GPCR polypeptide is detected.
• a test compound which binds to the RTA-like-GPCR polypeptide is thereby identified as a potential agent for decreasing the activity of RTA-like-GPCR.
• Another embodiment of the invention is a method of screening for agents which decrease the activity of RTA-like-GPCR.
• a test compound is contacted with a polynucleotide encoding a RTA-like-GPCR polypeptide, wherein the polynucleotide comprises a nucleotide sequence selected from the group consisting of:
• nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 1 ;
• a test compound which binds to the polynucleotide is identified as a potential agent for decreasing the activity of RTA-like-GPCR.
• the agent can work by decreasing the amount of the RTA-like-GPCR through interacting with the RTA-like-GPCR mRNA.
• Another embodiment of the invention is a method of screening for agents which regulate the activity of RTA-like-GPCR.
• a test compound is contacted with a RTA- like-GPCR polypeptide comprising an amino acid sequence selected from the group consisting of:
• amino acid sequences which are at least about 50% identical to the amino acid sequence shown in SEQ ID NO: 2;
• a RTA-like-GPCR activity of the polypeptide is detected.
• a test compound which increases RTA-like-GPCR activity of the polypeptide relative to RTA-like-GPCR activity in the absence of the test compound is thereby identified as a potential agent for increasing the activity of RTA-like-GPCR.
• a test compound which decreases RTA-like-GPCR activity of the polypeptide relative to RTA-like-GPCR activity in the absence of the test compound is thereby identified as a potential agent for decreasing the activity of RTA-like-GPCR.
• Even another embodiment of the invention is a method of screening for agents which decrease the activity of RTA-like-GPCR.
• a test compound is contacted with a RTA- like-GPCR product of a polynucleotide which comprises a nucleotide sequence selected from the group consisting of:
• nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 1;
• a test compound which binds to the RTA-like-GPCR product is thereby identified as a potential agent for decreasing the activity of RTA-like-GPCR.
• Still another embodiment of the invention is a method of reducing the activity of RTA-like-GPCR.
• a cell is contacted with a reagent which specifically binds to a polynucleotide encoding a RTA-like-GPCR polypeptide or the product encoded by the polynucleotide, wherein the polynucleotide comprises a nucleotide sequence selected from the group consisting of:
• nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 1;
• RTA-like-GPCR activity in the cell is thereby decreased.
• the invention thus provides an RTA-like G protein-coupled receptor which can be used to identify RTA analogs as well as compounds which may act as somatostatin antagonists at the receptor site.
• RTA-like G-protein coupled receptor and fragments thereof also are useful in raising specific antibodies which can block the receptor.
• Fig. 1 shows the DNA-sequence encoding a RTA-like-GPCR polypeptide.
• Fig. 2 shows the amino acid sequence deduced from the DNA- sequence of Fig.1.
• the invention relates to an isolated polynucleotide encoding a RTA-like-GPCR polypeptide and being selected from the group consisting of:
• amino acid sequences which are at least about 50% identical to
• RTA-like G protein-coupled receptor RTA-like-GPCR
• RTA-like-GPCR RTA-like G protein-coupled receptor
• agents which regulate it can be used in therapeutic methods to treat disorders such as bacterial, fungal, protozoan, and viral infections, particularly those caused by
• HIN viruses pain, cancers, anorexia, bulimia, asthma, Parkinson's diseases, acute heart failure, hypotension, hypertension, urinary retention, osteoporosis, angina pectoris, myocardial infarction, ulcers, asthma, allergies, benign prostatic hypertrophy, and psychotic and neurological disorders, including anxiety, schizophrenia, manic depression, delirium, dementia, several mental retardation, and dyskinesias, such as Huntington's disease and Tourett's syndrome.
• Human RTA-like GPCR also can be used to screen for receptor agonists and antagonists.
• RTA-like-GPCR polypeptides according to the invention comprise an amino acid sequence shown in SEQ ID NO:2, a portion of that sequence, or a biologically active variant thereof, as defined below.
• An RTA-like-GPCR polypeptide of the invention therefore can be a portion of an RTA-like-GPCR protein, a full-length RTA-like- GPCR protein, or a fusion protein comprising all or a portion of an RTA-like-GPCR protein.
• An amino acid sequence of human RTA-like GPCR is shown in SEQ ID NO:2.
• Transmembrane helices are present from amino acids 32 to 54, 62 to 82, 116 to 138, 152 to 173, 192 to 214, 227 to 249, and 262 to 288.
• RTA-like-GPCR polypeptide variants which are biologically active, i.e., retain the ability to bind a ligand to produce a biological effect, such as cyclic AMP formation, mobilization of intracellular calcium, or phosphoinositide metabolism, also are RTA- like- GPCR polypeptides.
• naturally or non-naturally occurring RTA-like- GPCR polypeptide variants have amino acid sequences which are at least about 50, preferably about 75, 90, 96, or 98% identical to an amino acid sequence shown in SEQ ID NO:2 or a fragment thereof. Percent identity between a putative RTA-like-
• GPCR polypeptide variant and an amino acid sequence of SEQ ID NO:2 is determined using the Blast2 alignment program.
• Variations in percent identity can be due, for example, to amino acid substitutions, insertions, or deletions.
• Amino acid substitutions are defined as one for one amino acid replacements. They are conservative in nature when the substituted amino acid has similar structural and/or chemical properties. Examples of conservative replacements are substitution of a leucine with an isoleucine or valine, an aspartate with a glutamate, or a threonine with a serine.
• Amino acid insertions or deletions are changes to or within an amino acid sequence.
• RTA-like-GPCR polypeptides typically fall in the range of about 1 to 5 amino acids.
• Guidance in determining which amino acid residues can be substituted, inserted, or deleted without abolishing biological or immunological activity of an RTA-like-GPCR polypeptide can be found using computer programs well known in the art, such as DNASTAR software. Wliether an amino acid change results in a biologically active RTA-like-GPCR polypeptide can readily be determined by assaying for binding to a ligand or by conducting a functional assay, as described for example, in the specific Examples, below.
• Fusion proteins can comprise at least 5, 6, 8, 10, 25, or 50 or RTA-like contiguous amino acids of an amino acid sequence shown in SEQ ID NO:2. Fusion proteins are useful for generating antibodies against RTA-like-GPCR polypeptide amino acid sequences and for use in various assay systems. For example, fusion proteins can be used to identify proteins which interact with portions of an RTA-like-GPCR polypeptide. Protein affinity chromatography or library-based assays for protein- protein interactions, such as the yeast two-hybrid or phage display systems, can be used for this purpose. Such methods are well known in the art and also can be used as drug screens.
• An RTA-like-GPCR polypeptide fusion protein comprises two polypeptide segments fused together by means of a peptide bond.
• the first polypeptide segment comprises at least 5, 6, 8, 10, 25, or 50 or RTA-like contiguous amino acids of SEQ ID NO:2 or from a biologically active variant, such as those described above.
• the first polypeptide segment also can comprise full-length RTA-like-GPCR protein.
• the second polypeptide segment can be a full-length protein or a protein fragment.
• Proteins commonly used in fusion protein construction include ⁇ -galactosidase, ⁇ - glucuronidase, green fluorescent protein (GFP), autofluorescent proteins, including blue fluorescent protein (BFP), glutathione-S-transferase (GST), luciferase, horseradish peroxidase (HRP), and chloramphenicol acetyltransferase (CAT).
• epitope tags are used in fusion protein constructions, including histidine (His) tags, FLAG tags, influenza hemagglutinin (HA) tags, Myc tags, VSV- G tags, and thioredoxin (Trx) tags.
• Other fusion constructions can include maltose binding protein (MBP), S-tag, Lex a DNA binding domain (DBD) fusions, GAL4
• a fusion protein also can be engineered to contain a cleavage site located between the RTA-like-GPCR polypeptide-encoding sequence and the heterologous protein sequence, so that the RTA-like-GPCR polypeptide can be cleaved and purified away from the heterologous moiety.
• a fusion protein can be synthesized chemically, as is known in the art.
• a fusion protein is produced by covalently linking two polypeptide segments or by standard procedures in the art of molecular biology.
• Recombinant DNA methods can be used to prepare fusion proteins, for example, by making a DNA construct which comprises coding sequences selected from SEQ ID NO:l in proper reading frame with nucleotides encoding the second polypeptide segment and expressing the DNA construct in a host cell, as is known in the art.
• Many kits for constructing fusion proteins are available from companies such as Promega Corporation (Madison, WI), Stratagene (La Jolla, CA), CLONTECH (Mountain View, CA),
• Species homologs of human RTA-like-GPCR polypeptide can be obtained using RTA-like-GPCR polypeptide polynucleotides (described below) to make suitable probes or primers for screening cDNA expression libraries from other species, such as mice, monkeys, or yeast, identifying cDNAs which encode homologs of RTA- like-GPCR polypeptide, and expressing the cDNAs as is known in the art.
• An RTA-like-GPCR polynucleotide can be single- or double-stranded and comprises a coding sequence or the complement of a coding sequence for an RTA-like-GPCR polypeptide.
• a coding sequence for human RTA-like-GPCR is shown in SEQ ED NO:l.
• nucleotide sequences encoding human RTA-like-GPCR polypeptides as well as homologous nucleotide sequences which are at least about 50, preferably about 75, 90, 96, or 98% identical to the nucleotide sequence shown in SEQ ID NO:l also are RTA-like-GPCR polynucleotides. Percent sequence identity between the sequences of two polynucleotides is determined using computer programs such as
• ALIGN which employ the FASTA algorithm, using an affine gap search with a gap open penalty of -12 and a gap extension penalty of -2.
• cDNA Complementary DNA
• Variants and homologs of the RTA-like-GPCR polynucleotides described above also are RTA-like-GPCR polynucleotides.
• homologous RTA-like-GPCR polynucleotide sequences can be identified by hybridization of candidate polynucleotides to known RTA-like-GPCR polynucleotides under stringent conditions, as is known in the art.
• homologous sequences can be identified which contain at most about 25-30% basepair mismatches.
• RTA-like preferably, homologous nucleic acid strands contain 15-25% basepair mismatches, even more preferably 5-15% basepair mismatches.
• Species homologs of the RTA-like-GPCR polynucleotides disclosed herein also can be identified by making suitable probes or primers and screening cDNA expression libraries from other species, such as mice, monkeys, or yeast.
• Human variants of RTA-like-GPCR polynucleotides can be identified, for example, by screening human cDNA expression libraries. It is well known that the T m of a double-stranded DNA decreases by 1-1.5 °C with every 1% decrease in homology (Bonner et al, J. Mol.
• Variants of human RTA-like-GPCR polynucleotides or RTA- like-GPCR polynucleotides of other species can therefore be identified by hybridizing a putative homologous RTA-like-GPCR polynucleotide with a polynucleotide having a nucleotide sequence of SEQ ID NO:l or the complement thereof to form a test hybrid.
• the melting temperature of the test hybrid is compared with the melting temperature of a hybrid comprising transformylase polynucleotides having perfectly complementary nucleotide sequences, and the number or percent of basepair mismatches within the test hybrid is calculated.
• Nucleotide sequences which hybridize to transformylase polynucleotides or their complements following stringent hybridization and/or wash conditions also are RTA- like-GPCR polynucleotides.
• Stringent wash conditions are well known and understood in the art and are disclosed, for example, in Sambrook et al, MOLECULAR CLONING: A LABORATORY MANUAL, 2d ed., 1989, at pages 9.50-9.51.
• a combination of temperature and salt concentration should be chosen that is approximately 12-20 °C below the calculated T m of the hybrid under study.
• the T m of a hybrid between an RTA-like- GPCR polynucleotide having a nucleotide sequence shown in SEQ ID NO:l or the complement thereof and a polynucleotide sequence which is at least about 50, preferably about 75, 90, 96, or 98% identical to one of those nucleotide sequences can be calculated, for example, using the equation of Bolton and McCarthy, Proc. Natl Acad. Sci. U.S.A. 48, 1390 (1962):
• Stringent wash conditions include, for example, 4X SSC at 65 °C, or 50% formamide, 4X SSC at 42 °C, or 0.5X SSC, 0.1% SDS at 65 °C.
• Highly stringent wash conditions include, for example, 0.2X SSC at 65 °C.
• RTA-like-GPCR polynucleotide can be isolated free of other cellular components such as membrane components, proteins, and lipids.
• Polynucleotides can be made by a cell and isolated using standard nucleic acid purification techniques, or synthesized using an amplification technique, such as the polymerase chain reaction (PCR), or by using an automatic synthesizer. Methods for isolating polynucleotides are routine and are known in the art. Any such technique for obtaining a polynucleotide can be used to obtain isolated RTA-like-GPCR polynucleotides.
• restriction enzymes and probes can be used to isolate polynucleotide fragments which comprises RTA-like-GPCR nucleotide sequences. Isolated polynucleotides are in preparations which are free or at least 70, 80, or 90% free of other molecules.
• RTA-like oncogene-related-GPCR cDNA molecules can be made with standard molecular biology techniques, using RTA-like-GPCR mRNA as a template.
• RTA- like-GPCR cDNA molecules can thereafter be replicated using molecular biology techniques known in the art and disclosed in manuals such as Sambrook et al. (1989).
• An amplification technique, such as PCR can be used to obtain additional copies of polynucleotides of the invention, using either human genomic DNA or cDNA as a template.
• RTA-like- GPCR polynucleotides can be synthesized using synthetic chemistry techniques to synthesizes RTA-like- GPCR polynucleotides.
• the degeneracy of the genetic code allows alternate nucleotide sequences to be synthesized which will encode an RTA-like-GPCR polypeptide having, for example, an amino acid sequence shown in SEQ ID NO: 2 or a biologically active variant thereof.
• PCR-based methods can be used to extend the nucleic acid sequences encoding the disclosed portions of human RTA-like-GPCR polypeptide to detect upstream sequences such as promoters and regulatory elements.
• restriction-site PCR uses universal primers to retrieve unknown sequence adjacent to a known locus (Sarkar, PCR Methods Applic. 2, 318-322, 1993). Genomic DNA is first amplified in the presence of a primer to a linker sequence and a primer specific to the known region. The amplified sequences are then subjected to a second round of PCR with the same linker primer and another specific primer internal to the first one. Products of each round of PCR are transcribed with an appropriate RNA polymerase and sequenced using reverse transcriptase.
• Inverse PCR also can be used to amplify or extend sequences using divergent primers based on a known region (Triglia et al, Nucleic Acids Res. 16, 8186, 1988). Primers can be designed using commercially available software, such as OLIGO 4.06 Primer
• the method uses several restriction enzymes to generate a suitable fragment in the known region of a gene. The fragment is then circularized by intramolecular ligation and used as a PCR template.
• capture PCR involves PCR amplification of DNA fragments adjacent to a known sequence in human and yeast artificial chromosome DNA (Lagerstrom et al, PCR Methods Applic. 1, 111-119, 1991).
• multiple restriction enzyme digestions and ligations also can be used to place an engineered double-stranded sequence into an unknown fragment of the DNA molecule before performing PCR.
• Randomly-primed libraries are preferable, in that they will contain more sequences which contain the 5' regions of genes. Use of a randomly primed library may be especially preferable for situations in which an oligo d(T) library does not yield a full-length cDNA. Genomic libraries can be useful for extension of sequence into 5' non-transcribed regulatory regions.
• capillary electrophoresis systems can be used to analyze the size or confirm the nucleotide sequence of PCR or sequencing products.
• capillary sequencing can employ flowable polymers for electrophoretic separation, four different fluorescent dyes (one for each nucleotide) which are laser activated, and detection of the emitted wavelengths by a charge coupled device camera.
• Output/light intensity can be converted to electrical signal using appropriate software (e.g. GENOTYPER and Sequence NAVIGATOR, Perkin Elmer), and the entire process from loading of samples to computer analysis and electronic data display can be computer controlled.
• Capillary electrophoresis is especially preferable for the sequencing of small pieces of DNA which might be present in limited amounts in a particular sample.
• RTA-like-GPCR polypeptides can be obtained, for example, by purification from human cells, by expression of RTA-like-GPCR polynucleotides, or by direct chemical synthesis.
• RTA-like-GPCR polypeptides can be purified from any human cell which expresses the receptor, including host cells which have been transfected with RTA-like-GPCR polynucleotides. Gut, vas deferens, uterus, aorta, and cerebellum are particularly useful sources of RTA-like-GPCR polypeptides.
• a purified RTA-like-GPCR polypeptide is separated from other compounds which normally associate with the RTA- like-GPCR polypeptide in the cell, such as certain proteins, carbohydrates, or lipids, using methods well-known in the art. Such methods include, but are not limited to, size exclusion chromatography, ammonium sulfate fractionation, ion exchange chromatography, affinity chromatography, and preparative gel electrophoresis.
• RTA-like-GPCR polypeptide can be conveniently isolated as a complex with its associated G protein, as described in the specific examples, below.
• a preparation of purified RTA-like-GPCR polypeptides is at least 80% pure; preferably, the preparations are 90%, 95%, or 99% pure. Purity of the preparations can be assessed by any means known in the art, such as SDS-polyacrylamide gel electrophoresis. Expression of RTA-like-GPCR Polynucleotides
• an RTA-like-GPCR polynucleotide can be inserted into an expression vector which contains the necessary elements for the transcription and translation of the inserted coding sequence.
• Methods which are well known to those skilled in the art can be used to construct expression vectors containing sequences encoding RTA-like-GPCR polypeptides and appropriate transcriptional and translational control elements. These methods include in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination. Such techniques are described, for example, in Sambrook et al.
• a variety of expression vector/host systems can be utilized to contain and express sequences encoding an RTA-like-GPCR polypeptide.
• microorganisms such as bacteria transformed with recombinant bacteriophage, plasmid, or cosmid DNA expression vectors; yeast transformed with yeast expression vectors, insect cell systems infected with virus expression vectors (e.g., baculo virus), plant cell systems transformed with virus expression vectors (e.g., cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or with bacterial expression vectors (e.g., Ti or pBR322 plasmids), or animal cell systems.
• microorganisms such as bacteria transformed with recombinant bacteriophage, plasmid, or cosmid DNA expression vectors
• yeast transformed with yeast expression vectors insect cell systems infected with virus expression vectors (e.g., baculo virus), plant cell systems transformed with virus expression vectors (e.g., cauliflower mosaic virus, CaMV; tobacco mosaic virus,
• control elements or regulatory sequences are those non-translated regions of the vector — enhancers, promoters, 5 1 and 3' untranslated regions — which interact with host cellular proteins to carry out transcription and translation. Such elements can vary in their strength and specificity. Depending on the vector system and host utilized, any number of suitable transcription and translation elements, including constitutive and inducible promoters, can be used. For example, when cloning in bacterial systems, inducible promoters such as the hybrid lacZ promoter of the BLUESCRIPT phagemid (Stratagene, LaJolla, Calif.) or pSPORTl plasmid (Life
• the baculo virus polyhedrin promoter can be used in insect cells. Promoters or enhancers derived from the genomes of plant cells (e.g., heat shock, RUBISCO, and storage protein genes) or from plant viruses (e.g., viral promoters or leader sequences) can be cloned into the vector. In mammalian cell systems, promoters from mammalian genes or from mammalian viruses are preferable. If it is necessary to generate a cell line that contains multiple copies of a nucleotide sequence encoding an RTA-like-GPCR polypeptide, vectors based on SV40 or EBV can be used with an appropriate selectable marker.
• a number of expression vectors can be selected depending upon the use intended for the RTA-like-GPCR polypeptide. For example, when a large quantity of an RTA-like-GPCR polypeptide is needed for the induction of antibodies, vectors which direct high level expression of fusion proteins that are readily purified can be used. Such vectors include, but are not limited to, multifunctional E. coli cloning and expression vectors such as BLUESCRIPT (Stratagene).
• a sequence encoding the RTA-like-GPCR polypeptide can be ligated into the vector in frame with sequences for the amino-terminal Met and the subsequent 7 residues of ⁇ -galactosidase so that a hybrid protein is produced.
• pIN vectors Van Heeke & Schuster, J. Biol. Chem. 264, 5503-5509, 1989
• pGEX vectors Promega, Madison, Wis.
• GST glutathione S-transferase
• fusion proteins are soluble and can easily be purified from lysed cells by adsorption to glutathione-agarose beads followed by elution in the presence of free glutathione.
• Proteins made in such systems can be designed to include heparin, thrombin, or factor Xa protease cleavage sites so that the cloned polypeptide of interest can be released from the GST moiety at will.
• yeast Saccharomyces cerevisiae a number of vectors containing constitutive or inducible promoters such as alpha factor, alcohol oxidase, and PGH can be used.
• constitutive or inducible promoters such as alpha factor, alcohol oxidase, and PGH.
• sequences encoding RTA-like- GPCR polypeptides can be driven by any of a number of promoters.
• viral promoters such as the 35S and 19S promoters of CaMV can be used alone or in combination with the omega leader sequence from TMV (Takamatsu, EMBO J. 6, 307-311, 1987).
• plant promoters such as the small subunit of
• RUBISCO or heat shock promoters can be used (Coruzzi " et - al, EMBO J. 3, 1671- 1680, 1984; Broglie et al, Science 224, 838-843, 1984; Winter et al, Results Probl Cell Differ. 17, 85-105, 1991).
• These constructs can be introduced into plant cells by direct DNA transformation or by pathogen-mediated transfection. Such techniques are described in a number of generally available reviews (e.g., Hobbs or Murray, in
• An insect system also can be used to express an RTA-like-GPCR polypeptide.
• an insect system also can be used to express an RTA-like-GPCR polypeptide.
• Autographa californica nuclear polyhedrosis virus Autographa californica nuclear polyhedrosis virus
• AcNPV is used as a vector to express foreign genes in Spodoptera frugiperda cells or in Trichoplusia larvae. Sequences encoding RTA-like-GPCR polypeptides can be cloned into a non-essential region of the virus, such as the polyhedrin gene, and placed under control of the polyhedrin promoter. Successful insertion of RTA-like- GPCR polypeptides will render the polyhedrin gene inactive and produce recombinant virus lacking coat protein. The recombinant viruses can then be used to infect S. frugiperda cells or Trichoplusia larvae in which RTA-like-GPCR polypeptides can be expressed (Engelhard et al, Proc. Nat. Acad. Sci. 91, 3224-3227, 1994). Mammalian Expression Systems
• a number of viral-based expression systems can be used to express RTA-like-GPCR polypeptides in mammalian host cells.
• sequences encoding RTA-like-GPCR polypeptides can be ligated into an adenovirus transcription/translation complex comprising the late promoter and tripartite leader sequence. Insertion in a non-essential El or E3 region of the viral genome can be used to obtain a viable virus which is capable of expressing an RTA-like-GPCR polypeptide in infected host cells (Logan & Shenk, Proc. Natl Acad. Sci. 81, 3655-3659, 1984).
• transcription enhancers such as the
• Rous sarcoma virus (RSN) enhancer can be used to " increase expression in mammalian host cells.
• HACs Human artificial chromosomes
• 6M to 10M are constructed and delivered to cells via conventional delivery methods (e.g., liposomes, polycationic amino polymers, or vesicles).
• Specific initiation signals also can be used to achieve more efficient translation of sequences encoding RTA-like-GPCR polypeptides. Such signals include the ATG initiation codon and adjacent sequences. In cases where sequences encoding an
• RTA-like-GPCR polypeptide, its initiation codon, and upstream sequences are inserted into the appropriate expression vector, no additional transcriptional or translational control signals may be needed. However, in cases where only coding sequence, or a fragment thereof, is inserted, exogenous translational control signals
• the initiation codon should be in the correct reading frame to ensure translation of the entire insert.
• Exogenous translational elements and initiation codons can be of various origins, both natural and synthetic.
• the efficiency of expression can be enhanced by the inclusion of enhancers which are appropriate for the particular cell system which is used (see Scharf et al, Results Prob Cell Differ. 20, 125-162, 1994).
• enhancers which are appropriate for the particular cell system which is used (see Scharf et al, Results Prob Cell Differ. 20, 125-162, 1994).
• a host cell strain can be chosen for its ability to modulate the expression of the * ⁇ « * 5 inserted sequences or to process the expressed RTA-like-GPCR polypeptide in the desired fashion.
• modifications of the polypeptide include, but are not limited to, acetylation, carboxylation, glycosylation, phosphorylation, lipidation, and acylation.
• Post-translational processing which cleaves a "prepro" form of the polypeptide also can be used to facilitate correct insertion, folding and/or function.
• Different host cells which have specific cellular machinery and characteristic mechanisms for post-translational activities (e.g., CHO, HeLa, MDCK, HEK293, and WI38), are available from the American Type Culture Collection (ATCC; 10801 University Boulevard, Manassas, NA 20110-2209) and can be chosen to ensure the correct modification and processing of the foreign protein.
• ATCC American Type Culture Collection
• Stable expression is preferred for long-term, high-yield production of recombinant proteins.
• cell lines which stably express RTA-like-GPCR polypeptides can be transformed using expression vectors which can contain viral origins of replication and/or endogenous expression elements and a selectable marker gene on
• cells can be allowed to grow for 1-2 days in an enriched medium before they are switched to a selective medium.
• the purpose of the selectable marker is to confer resistance to selection, and its presence allows growth and recovery of cells which successfully express the introduced RTA-like-GPCR sequences. Resistant clones of stably trans-
• 25 formed cells can be proliferated using tissue culture techniques appropriate to the cell type. See, for example, ANIMAL CELL CULTURE, R.I. Freshney, ed., 1986.
• dhfr confers resistance to methotrexate (Wigler et al, Proc. Natl Acad. Sci. 77, 3567-70, 1980)
• npt confers resistance to the amino- glycosides, neomycin and G-418 (Colbere-Garapin et al, J. Mol. Biol. 150, 1-14,
• trpB allows cells to utilize indole in place of trypto- phan, or hisD, which allows cells to utilize histinol in place of histidine (Hartman & Mulligan, Proc. Natl. Acad. Sci. 85, 8047-51, 1988).
• Visible markers such as anthocyanins, ⁇ -glucuronidase and its substrate GUS, and luciferase and its substrate luciferin, can be used to identify transfonnants and to quantify the amount of transient or stable protein expression attributable to a specific vector system (Rhodes et al, Methods Mol. Biol. 55, 121-131, 1995).
• marker gene expression suggests that the RTA-like-GPCR polynucleotide is also present, its presence and expression may need to be confirmed. For example, if a sequence encoding an RTA-like-GPCR polypeptide is inserted within a marker gene sequence, transformed cells containing sequences which encode an RTA-like-GPCR polypeptide can be identified by the absence of marker gene function. Alternatively, a marker gene can be placed in tandem with a sequence encoding an RTA-like-GPCR polypeptide under the control of a single promoter. Expression of the marker gene in response to induction or selection usually indicates expression of the RTA-like-GPCR polynucleotide.
• host cells which contain an RTA-like-GPCR polynucleotide and which express an RTA-like-GPCR polypeptide can be identified by a variety of procedures known to those of skill in the art. These procedures include, but are not limited to, DNA-DNA or DNA-RNA hybridizations and protein bioassay or immunoassay techniques which include membrane, solution, or chip-based technologies for the detection and/or quantification of nucleic acid or protein. For example, the presence of a polynucleotide sequence encoding an RTA-like-GPCR polypeptide can be detected by DNA-DNA or DNA-RNA hybridization or amplification using probes or fragments or fragments of polynucleotides encoding an RTA-like-GPCR polypeptide.
• Nucleic acid amplification-based assays involve the use of oligo- nucleotides selected from sequences encoding an RTA-like-GPCR polypeptide to detect transfonnants which contain an RTA-like-GPCR polynucleotide.
• GPCR polypeptide using either polyclonal or monoclonal antibodies specific for the polypeptide, are known in the art. Examples include enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and fluorescence activated cell sorting (FACS). A two-site, monoclonal-based immunoassay using monoclonal antibodies reactive to two non-interfering epitopes on an RTA-like-GPCR polypeptide can be used, or a competitive binding assay can be employed. These and other assays are described in Hampton et al, SEROLOGICAL METHODS: A LABORATORY MANUAL, APS Press, St. Paul, Minn., 1990) and Maddox et al, J. Exp. Med. 158, 1211-1216, 1983).
• Means for producing labeled hybridization or PCR probes for detecting sequences related to polynucleotides encoding RTA-like-GPCR polypeptides include oligolabeling, nick translation, end-labeling, or PCR amplification using a labeled nucleotide.
• sequences encoding an RTA-like-GPCR polypeptide can be cloned into a vector for the production of an mRNA probe.
• vectors are known in the art, are commercially available, and can be used to synthesize RNA probes in vitro by addition of labeled nucleotides and an appropriate RNA polymerase such as T7, T3, or SP6. These procedures can be conducted using a variety of commercially available kits (Amersham Pharmacia Biotech, Promega, and US Biochemical).
• Suitable reporter molecules or labels which can be used for ease of detection include radionuclides, enzymes, and fluorescent, chemiluminescent, or chromogenic agents, as well as substrates, cofactors, inhibitors, magnetic particles, and the like.
• Host cells transformed with nucleotide sequences encoding an RTA-like-GPCR polypeptide can be cultured under conditions suitable for the expression and recovery of the protein from cell culture.
• the polypeptide produced by a transformed cell can be secreted or contained intracellularly depending on the sequence and/or the vector used.
• expression vectors containing polynucleotides which encode RTA-like-GPCR polypeptides can be designed to contain signal sequences which direct secretion of soluble RTA-like-GPCR polypeptides through a prokaryotic or eukaryotic cell membrane or which direct the membrane insertion of membrane-bound RTA-like-GPCR polypeptide.
• purification facilitating domains include, but are not limited to, metal chelating peptides such as histidine-tryptophan modules that allow purification on immobilized metals, protein A domains that allow purification on immobilized immunoglobulin, and the domain utilized in the FLAGS extension/affinity purification system (Immunex Corp., Seattle, Wash.).
• cleavable linker sequences such as those specific for Factor Xa or enterokinase (Invitrogen, San Diego, CA) between the purification domain and the RTA-like-GPCR polypeptide also can be used to facilitate purification.
• One such expression vector provides for expression of a fusion protein containing an RTA-like-GPCR polypeptide and 6 histidine residues preceding a thioredoxin or an enterokinase cleavage site. The histidine residues facilitate purification by IMAC (immobilized metal ion affinity chromatography, as described in Porath et al, Prot. Exp.
• enterokinase cleavage site provides a means for purifying the RTA-like-GPCR polypeptide from the fusion protein.
• Vectors which contain fusion proteins are disclosed in Kroll et al, DNA Cell Biol. 72, 441-453, 1993.
• Sequences encoding an RTA-like-GPCR polypeptide can be synthesized, in whole or in part, using chemical methods well known in the art (see Caruthers et al, Nucl Acids Res. Symp. Ser. 215-223, 1980; Horn et al. Nucl. Acids Res. Symp. Ser. 225- 232, 1980).
• an RTA-like-GPCR polypeptide itself can be produced using chemical methods to synthesize its amino acid sequence, such as by direct peptide synthesis using solid-phase techniques (Merrifield, J. Am. Chem. Soc. 85, 2149-2154, 1963; Roberge et al, Science 269, 202-204, 1995). Protein synthesis can be performed using manual techniques or by automation. Automated synthesis can be achieved, for example, using Applied Biosystems 431 A Peptide Synthesizer
• fragments of RTA-like-GPCR polypeptides can be separately synthesized and combined using chemical methods to produce a full-length molecule.
• the newly synthesized peptide can be substantially purified by preparative high performance liquid chromatography (e.g., Creighton, PROTEINS: STRUCTURES AND MOLECULAR PRINCIPLES, WH. Freeman and Co., New York, N.Y., 1983).
• the composition of a synthetic RTA-like-GPCR polypeptide can be confirmed by amino acid analysis or sequencing (e.g., the Edman degradation procedure; see Creighton, supra). Additionally, any portion of the amino acid sequence of the RTA-like-GPCR polypeptide can be altered during direct synthesis and/or combined using chemical methods with sequences from other proteins to produce a variant polypeptide or a fusion protein.
• RTA-like-GPCR polypeptide-encoding nucleotide sequences possessing non- 5 naturally occurring codons For example, codons preferred by a particular prokaryotic or eukaryotic host can be selected to increase the rate of protein expression or to produce an RNA transcript having desirable properties, such as a half-life which is longer than that of a transcript generated from the naturally occurring sequence.
• nucleotide sequence disclosed herein can be engineered using methods generally known in the art to alter RTA-like-GPCR polypeptide-encoding sequences for a variety of reasons, including but not limited to, alterations which modify the cloning, processing, and or expression of the polypeptide or mRNA product.
• DNA shuffling by random fragmentation and PCR reassembly of gene fragments and synthetic 5 oligonucleotides can be used to engineer the nucleotide sequences.
• site-directed mutagenesis can be used to insert new restriction sites, alter glycosylation patterns, change codon preference, produce splice variants, introduce mutations, and so forth.
• Antibody as used herein includes intact immunoglobulin molecules, as well as fragments thereof, such as Fab, F(ab') 2 , 5 and Fv, which are capable of binding an epitope of an RTA-like-GPCR polypeptide.
• epitopes typically, at least 6, 8, 10, or 12 contiguous amino acids are required to form an epitope.
• epitopes which involve non-contiguous amino acids may require more, e.g., at least 15, 25, or 50 amino acids.
• An antibody which specifically binds to an epitope of an RTA-like-GPCR polypeptide can be used therapeutically, as well as in immunochemical assays, such as Weste ⁇ i blots, ELISAs, radioimmunoassays, immunohistochemical assays, immuno- precipitations, or other immunochemical assays known in the art.
• immunochemical assays such as Weste ⁇ i blots, ELISAs, radioimmunoassays, immunohistochemical assays, immuno- precipitations, or other immunochemical assays known in the art.
• Various immunoassays can be used to identify antibodies having the desired specificity. Numerous protocols for competitive binding or immunoradiometric assays are well known in the art. Such immunoassays typically involve the measurement of complex formation between an immunogen and an antibody which specifically binds to the immunogen.
• an antibody which specifically binds to an RTA-like-GPCR polypeptide provides a detection signal at least 5-, 10-, or 20-fold higher than a detection signal provided with other proteins when used in an immunochemical assay.
• antibodies which specifically bind to RTA-like-GPCR polypeptides do not detect other proteins in immunochemical assays and can immunoprecipitate an RTA-like- GPCR polypeptide from solution.
• RTA-like-GPCR polypeptides can be used to immunize a mammal, such as a mouse, rat, rabbit, guinea pig, monkey, or human, to produce polyclonal antibodies.
• a mammal such as a mouse, rat, rabbit, guinea pig, monkey, or human
• an RTA-like-GPCR polypeptide can be conjugated to a carrier protein, such as bovine serum albumin, thyroglobulin, and keyhole limpet hemocyanin.
• a carrier protein such as bovine serum albumin, thyroglobulin, and keyhole limpet hemocyanin.
• various adjuvants can be used to increase the immunological response.
• adjuvants include, but are not limited to, Freund's adjuvant, mineral gels (e.g., aluminum hydroxide), and surface active substances (e.g.
• BCG Bacilli Calmette-Gueri
• Corynebacterium parvum are especially useful.
• Monoclonal antibodies which specifically bind to an RTA-like-GPCR polypeptide can be prepared using any technique which provides for the production of antibody molecules by continuous cell lines in culture. These techniques include, but are not limited to, the hybridoma technique, the human B-cell hybridoma technique, and the
• chimeric antibodies the splicing of mouse antibody genes to human antibody genes to obtain a molecule with appropriate antigen specificity and biological activity, can be used (Morrison et al, Proc. Natl. Acad. Sci. 81, 6851-6855, 1984; Neuberger et al, Nature 312, 604-608, 1984; Takeda et al, Nature 314, 452-454, 1985).
• Monoclonal and other antibodies also can be "humanized” to prevent a patient from mounting an immune response against the antibody when it is used therapeutically. Such antibodies may be sufficiently similar in sequence to human antibodies to be vised directly in therapy or may require alteration of a few key residues.
• rodent antibodies and human sequences can be minimized by replacing residues which differ from those in the human sequences by site directed mutagenesis of individual residues or by grating of entire complementarity determining regions.
• humanized antibodies can be produced using recombinant methods, as described in GB2188638B.
• Antibodies which specifically bind to an RTA-like-GPCR polypeptide can contain antigen binding sites which are either partially or fully humanized, as disclosed in U.S. 5,565,332.
• single chain antibodies can be adapted using methods known in the art to produce single chain antibodies which specifically bind to RTA-like-GPCR polypeptides.
• Antibodies with related specificity, but of distinct idiotypic composition can be generated by chain shuffling from random combinatorial immunoglobin libraries (Burton, Proc. Natl. Acad. Sci. 88,
• Single-chain antibodies also can be constructed using a DNA amplification method, such as PCR, using hybridoma cDNA as a template (Thirion et al, 1996, Eur. J. Cancer Prev. 5, 507-1 1).
• Single-chain antibodies can be mono- or bispecific, and can be bivalent or tetravalent. Construction of tetravalent, bispecific single-chain antibodies is taught, for example, in Coloma & Morrison, 1997, Nat. Biotechnol 15, 159-63. Construction of bivalent, bispecific single-chain antibodies is taught in Mallender & Voss, 1994, J Biol. Chem. 269, 199-206.
• a nucleotide sequence encoding a single-chain antibody can be constructed using manual or automated nucleotide synthesis, cloned into an expression construct using standard recombinant DNA methods, and introduced into a cell to express the coding sequence, as described below.
• single-chain antibodies can be produced directly using, for example, filamentous phage technology (Verhaar et al, 1995, Int. J. Cancer 61, 497-501; Nicholls et al, 1993, J Immunol. Meth. 165, 81-
• Antibodies which specifically bind to RTA-like-GPCR polypeptides also can be produced by inducing in vivo production in the lymphocyte population or by screening immunoglobulin libraries or panels of highly specific binding reagents as disclosed in the literature (Orlandi et al, Proc. Natl. Acad. Sci. 86, 3833-3837, 1989; Winter et al, Nature 349, 293-299, 1991).
• chimeric antibodies can be constructed as disclosed in
• Binding proteins which are derived from immunoglobulins and which are multivalent and multispecific, such as the "diabodies" described in WO 94/13804, also can be prepared.
• Antibodies according to the invention can be purified by methods well known in the art. For example, antibodies can be affinity purified by passage over a column to which an RTA-like-GPCR polypeptide is bound. The bound antibodies can then be eluted from the column using a buffer with a high salt concentration.
• Antisense Oligonucleotides can be affinity purified by passage over a column to which an RTA-like-GPCR polypeptide is bound. The bound antibodies can then be eluted from the column using a buffer with a high salt concentration.
• Antisense oligonucleotides are nucleotide sequences which are complementary to a specific DNA or RNA sequence. Once introduced into a cell, the complementary nucleotides combine with natural sequences produced by the cell to form complexes and block either transcription or translation. Preferably, an antisense oligonucleotide is at least 11 nucleotides in length, but can be at least 12, 15, 20, 25, 30, 35, 40, 45, or 50 or more nucleotides long. Longer sequences also can be used. Antisense oligonucleotide molecules can be provided in a DNA construct and introduced into a cell as described above to decrease the level of RTA-like-GPCR gene products in the cell. " -
• Antisense oligonucleotides can be deoxyribonucleotides, ribonucleotides, or a combination of both. Oligonucleotides can be synthesized manually or by an automated synthesizer, by covalently linking the 5' end of one nucleotide with the 3' end of another nucleotide with non-phosphodiester internucleotide linkages such alkyl- phosphonates, phosphorothioates, phosphorodithioates, alkylphosphonothioates, alkylphosphonates, phosphoramidates, phosphate esters, carbamates, acetamidate, carboxymethyl esters, carbonates, and phosphate triesters. See Brown, Meth. Mol. Biol. 20, 1-8, 1994; Sonveaux, Meth. Mol. Biol. 26, 1-72, 1994; Uhlmann et al,
• Modifications of RTA-like-GPCR gene expression can be obtained by designing antisense oligonucleotides which will form duplexes to the control, 5', or regulatory regions of the RTA-like-GPCR gene. Oligonucleotides derived from the transcription initiation site, e.g., between positions -10 and +10 from the start site, are preferred. Similarly, inhibition can be achieved using "triple helix" base-pairing methodology. Triple helix pairing is useful because it causes inhibition of the ability of the double helix to open sufficiently for the binding of polymerases, transcription factors, or chaperons.
• An antisense oligonucleotide also can be designed to block translation of mRNA by preventing the transcript from binding to ribosomes.
• Antisense oligonucleotides which comprise, for example, 2, 3, 4, or 5 or more stretches of contiguous nucleotides which are precisely complementary to an RTA-like-GPCR polynucleotide, each separated by a stretch of contiguous nucleotides which are not complementary to adjacent RTA-like-GPCR nucleotides, can provide sufficient targeting specificity for RTA-like-GPCR mRNA.
• each stretch of complementary contiguous nucleotides is at least 4, 5, 6, 7, or 8 or more nucleotides in length.
• Non-complementary intervening sequences are preferably 1, 2, 3, or 4 nucleotides in length.
• One skilled in the art can easily use the calculated melting point of an antisense-sense pair to determine the degree of mismatching which will be tolerated between a particular antisense oligonucleotide and a particular RTA-like-GPCR polynucleotide sequence.
• Antisense oligonucleotides can be modified without affecting their ability to hybridize to an RTA-like-GPCR polynucleotide. These modifications can be internal or at one or both ends of the antisense molecule.
• internucleoside phosphate linkages can be modified by adding cholesteryl or diamine moieties with varying numbers of carbon residues between the amino groups and terminal ribose.
• Modified bases and or sugars such as arabinose instead of ribose, or a 3', 5'- substituted oligonucleotide in which the 3' hydroxyl group or the 5 1 phosphate group are substituted, also can be employed in a modified antisense oligonucleotide.
• modified oligonucleotides can be prepared by methods well known in the art. See, e.g., Agrawal et al, Trends Biotechnol. 10, 152-158, 1992; Uhlmann et al, Chem.
• Ribozymes are RNA molecules with catalytic activity. See, e.g., Cech, Science 236, 1532-1539; 1987; Cech, Ann. Rev. Biochem. 59, 543-568; 1990, Cech, Curr. Opin. Struct. Biol. 2, 605-609; 1992, Couture & Stinchcomb, Trends Genet. 12, 510-515,
• Ribozymes can be used to inhibit gene function by cleaving an RNA sequence, as is known in the art (e.g., Haseloff et al, U.S. Patent 5,641,673).
• the mechanism of ribozyme action involves sequence-specific hybridization of the ribozyme molecule to complementary target RNA, followed by endonucleolytic cleavage. Examples include engineered hammerhead motif ribozyme molecules that can specifically and efficiently catalyze endonucleolytic cleavage of specific nucleotide sequences.
• a coding sequence of an RTA-like-GPCR polynucleotide can be used to generate ribozymes which will specifically bind to mRNA transcribed from the RTA-like-
• GPCR polynucleotide Methods of designing and constructing ribozymes which can cleave other RNA molecules in trans in a highly sequence specific manner have been developed and described in the art (see Haseloff et al. Nature 334, 585-591, 1988).
• the cleavage activity of ribozymes can be targeted to specific RNAs by engineering a discrete "hybridization" region into the ribozyme.
• the hybridization region contains a sequence complementary to the target RNA and thus specifically hybridizes with the target (see, for example, Gerlach et al, EP 321,201).
• Specific ribozyme cleavage sites within an RTA-like-GPCR RNA target can be identified by scanning the target molecule for ribozyme cleavage sites which include the following sequences: GUA, GUU, and GUC. Once identified, short RNA sequences of between 15 and 20 ribonucleotides corresponding to the region of the target RNA containing the cleavage site can be evaluated for secondary structural features which may render the target inoperable. Suitability of candidate RTA-like- GPCR RNA targets also can be evaluated by testing accessibility to hybridization with complementary oligonucleotides using ribonuclease protection assays.
• the nucleotide sequence shown in SEQ ID NO:l and its complement provide sources of suitable hybridization region sequences. Longer complementary sequences can be used to increase the affinity of the hybridization sequence for the target.
• the hybridizing and cleavage regions of the ribozyme can be integrally related such that upon hybridizing to the target RNA through the complementary regions, the catalytic region of the ribozyme can cleave the target.
• Ribozymes can be introduced into cells as part of a DNA construct. Mechanical methods, such as microinjection, liposome-mediated transfection, electroporation, or calcium phosphate precipitation, can be used to introduce a ribozyme-containing DNA construct.
• a ribozyme-encoding DNA construct can include transcriptional regulatory elements, such as a promoter element, an enhancer or UAS element, and a transcriptional terminator signal, for controlling transcription of ribozymes in the cells.
• ribozymes can be engineered so that ribozyme expression will occur in response to factors which induce expression of a target gene. Ribozymes also can be engineered to provide an additional level of regulation, so that destruction of mRNA occurs only when both a ribozyme and a target gene are induced in the cells.
• the invention provides assays for screening test compounds which bind to or modulate the activity of an RTA-like-GPCR polypeptide or an RTA-like-GPCR polynucleotide.
• a test compound preferably binds to an RTA-like-GPCR poly- peptide or polynucleotide. More preferably, a test compound decreases or increases a biological effect mediated via human RTA-like-GPCR by at least about 10, preferably about 50, more preferably about 75, 90, or 100% relative to the absence of the test compound.
• Test compounds can be pharmacologic agents already known in the art or can be compounds previously unknown to have any pharmacological activity.
• the compounds can be naturally occurring or designed in the laboratory. They can be isolated from microorganisms, animals, or plants, and can be produced recombi- nantly, or synthesized by chemical methods known in the art. If desired, test compounds can be obtained using any of the numerous combinatorial library methods known in the art, including but not limited to, biological libraries, spatially addressable parallel solid phase or solution phase libraries, synthetic library methods requiring deconvolution, the "one-bead one-compound” library method, and synthetic library methods using affinity chromatography selection.
• the biological library approach is limited to polypeptide libraries, while the other four approaches are applicable to polypeptide, non-peptide oligomer, or small molecule libraries of compounds. See Lam, Anticancer Drug Des. 12, 145, 1997.
• Test compounds can be screened for the ability to bind to RTA-like-GPCR polypeptides or polynucleotides or to affect RTA-like-GPCR activity or RTA-like-
• GPCR gene expression using high throughput screening uses high throughput screening. Using high throughput screening, many discrete compounds can be tested in parallel so that large numbers of test compounds can be quickly screened.
• the most widely established techniques utilize 96-well microtiter plates. The wells of the microtiter plates typically require assay volumes that range from 50 to 500 ⁇ l.
• many instruments, materials, pipettors, robotics, plate ' washers, -and plate readers are commercially available to fit the 96-well format.
• free format assays or assays that have no physical barrier between samples, can be used.
• an assay using pigment cells (melanocytes) in a simple homogeneous assay for combinatorial peptide libraries is described by Jayawickreme et al, Proc. Natl. Acad. Sci. U.S.A. 19, 1614-18 (1994).
• the cells are placed under agarose in petri dishes, then beads that carry combinatorial compounds are placed on the surface of the agarose.
• the combinatorial compounds are partially released the compounds from the beads. Active compounds can be visualized as dark pigment areas because, as the compounds diffuse locally into the gel matrix, the active compounds cause the cells to change colors.
• Chelsky "Strategies for Screening Combinatorial Libraries: Novel and Traditional Approaches," reported at the First Annual Conference of The Society for Biomolecular Screening in Philadelphia, Pa. (Nov. 7-10, 1995).
• Chelsky placed a simple homogenous enzyme assay for carbonic anhydrase inside an agarose gel such that the enzyme in the gel would cause a color change throughout the gel.
• beads carrying combinatorial compounds via a photolinker were placed inside the gel and the compounds were partially released by UN-light. Compounds that inhibited the enzyme were observed as local zones of inhibition having less color change.
• test samples are placed in a porous matrix.
• One or more assay components are then placed within, on top of, or at the bottom of a matrix such as a gel, a plastic sheet, a filter, or other form of easily manipulated solid support.
• a matrix such as a gel, a plastic sheet, a filter, or other form of easily manipulated solid support.
• the test compound is preferably a small molecule which binds to and occupies the active site of the RTA-like-GPCR polypeptide, thereby making the ligand binding site inaccessible to substrate such that normal biological activity is prevented.
• small molecules include, but are not limited to, small peptides or peptide-like molecules.
• Potential ligands which bind to a polypeptide of the invention include, but are not limited to, the natural ligands of known RTA-like- GPCRs and analogues or derivatives thereof.
• Natural ligands of GPCRs include adrenomedullin, amylin, calcitonin gene related protein (CGRP), calcitonin, anandamide, serotonin, histamine, adrenalin, noradrenalin, platelet activating factor, thrombin, C5a, bradykinin, and chemokines.
• CGRP calcitonin gene related protein
• either the test compound or the RTA-like-GPCR polypeptide can comprise a detectable label, such as a fluorescent, radioisotopic, chemiluminescent, or enzymatic label, such as horseradish peroxidase, alkaline phosphatase, or luciferase.
• a detectable label such as a fluorescent, radioisotopic, chemiluminescent, or enzymatic label, such as horseradish peroxidase, alkaline phosphatase, or luciferase.
• Detection of a test compound which is bound to the RTA-like-GPCR polypeptide can then be accomplished, for example, by direct counting of radioemmission, by scintillation counting, or by determining conversion of an appropriate substrate to a detectable product.
• binding of a test compound to an RTA-like-GPCR polypeptide can be determined without labeling either of the interactants.
• a micro- physiometer can be used to detect binding of a test compound with an RTA-like- GPCR polypeptide.
• a microphysiometer e.g., CytosensorTM
• LAPS light-addressable potentiometric sensor
• Determining the ability of a test compound to bind to an RTA-like-GPCR poly- peptide also can be accomplished using a technology such as real-time Bimolecular
• BIA Interaction Analysis
• an RTA-like-GPCR polypeptide can be used as a "bait protein" in a two-hybrid assay or three-hybrid assay (see, e.g., U.S. Patent 5,283,317; Zervos et al, Cell 72, 223-232, 1993; Madura et al, J. Biol. Chem. 268,
• the two-hybrid system is based on the modular nature of most transcription factors, which consist of separable DNA-binding and activation domains. Briefly, the assay utilizes two different DNA constructs.
• polynucleotide encoding an RTA-like-GPCR polypeptide can be fused to a polynucleotide encoding the DNA binding domain of a known transcription factor (e.g. , GAL-4).
• a DNA sequence that encodes an unidentified protein (“prey” or “sample") can be fused to a polynucleotide that codes for the activation domain of the known transcription factor. If the "bait" and the "prey” proteins are able to interact in vivo to form an protein-dependent complex, the DNA-binding and activation domains of the transcription factor are brought into close proximity.
• reporter gene e.g., LacZ
• a reporter gene e.g., LacZ
• Expression of the reporter gene can be detected, and cell colonies containing the functional transcription factor can be isolated and used to obtain the DNA sequence encoding the protein which interacts with the RTA-like-GPCR polypeptide.
• either the RTA-like-GPCR polypeptide (or polynucleotide) or the test compound can be bound to a solid support.
• Suitable solid supports include, but are not limited to, glass or plastic slides, tissue culture plates, microtiter wells, tubes, silicon chips, or particles such as beads (including, but not limited to, latex, polystyrene, or glass beads).
• any method known in the art can be used to attach the RTA-like-GPCR polypeptide (or polynucleotide) or test compound to a solid support, including use of covalent and non-covalent linkages, passive absorption, or pairs of binding moieties attached respectively to the polypeptide (or polynucleotide) or test compound and the solid support.
• Test compounds are preferably bound to the solid support in an anay, so that the location of individual test compounds can be tracked. Binding of a test compound to an RTA-like-GPCR polypeptide (or polynucleotide) can be accomplished in any vessel suitable for containing the reactants. Examples of such vessels include microtiter plates, test tubes, and microcentrifuge tubes.
• the RTA-like-GPCR polypeptide is a fusion protein comprising a domain that allows the RTA-like-GPCR polypeptide to be bound to a solid support.
• glutathione-S-transferase fusion proteins can be adsorbed onto glutathione sepharose beads (Sigma Chemical, St. Louis, Mo.) or glutathione derivatized microtiter plates, which are then combined with the test compound or the test compound and the non-adsorbed RTA-like-GPCR polypeptide; the mixture is then incubated under conditions conducive to complex formation (e.g., at physiological conditions for salt and pH). Following incubation, the beads or microtiter plate wells are washed to remove any unbound components. Binding of the interactants can be determined either directly or indirectly, as described above. Alternatively, the complexes can be dissociated from the solid support before binding is determined.
• an RTA- like-GPCR polypeptide or polynucleotide
• a test compound can be immobilized utilizing conjugation of biotin and strep tavidin.
• Biotinylated RTA-like-GPCR polypeptides (or polynucleotides) or test compounds can be prepared from biotin-NHS- (N-hydroxysuccinimide) using techniques well known in the art (e.g., biotinylation kit, Pierce Chemicals, Rockford, 111.) and immobilized in the wells of streptavidin- coated 96 well plates (Pierce Chemical).
• biotinylation kit Pierce Chemicals, Rockford, 111.
• antibodies which specifically bind to an RTA-like-GPCR polypeptide, polynucleotide, or a test compound, but which do not interfere with a desired binding site, such as the active site of the RTA- like-GPCR polypeptide can be derivatized to the wells of the plate. Unbound target or protein can be trapped in the wells by antibody conjugation.
• GST-immobilized complexes include immunodetection of complexes using anti- bodies which specifically bind to the RTA-hke-GPCR polypeptide or test compound, enzyme-linked assays which rely on detecting an activity of the RTA-like-GPCR polypeptide, and SDS gel electrophoresis under non-reducing conditions.
• Any cell which comprises an RTA-like-GPCR polypeptide or polynucleotide can be used in a cell-based assay system.
• An RTA-like-GPCR polynucleotide can be naturally occurring in the cell or can be introduced using techniques such as those described above. Binding of the test compound to an RTA-like-GPCR polypeptide or polynucleotide is determined as described above. " -
• Test compounds can be tested for the ability to increase or decrease a biological effect of an RTA-like-GPCR polypeptide. Such biological effects can be determined using the functional assays described in the specific examples, below. Functional assays can be carried out after contacting either a purified RTA-like-GPCR polypeptide, a cell membrane preparation, or an intact cell with a test compound.
• a test compound which decreases a functional activity of an RTA-like-GPCR by at least about 10, preferably about 50, more preferably about 75, 90, or 100% is identified as a potential agent for decreasing RTA-like-GPCR activity.
• a test compound which increases RTA-like-GPCR activity by at least about 10, preferably about 50, more preferably about 75, 90, or 100% is identified as a potential agent for increasing RTA-like-GPCR activity.
• Such a screening procedure involves the use of melanophores which are transfected to express an RTA-like-GPCR polypeptide.
• a screening technique is described in WO 92/01810 published Feb. 6, 1992.
• an assay may be employed for screening for a compound which inhibits activation of the receptor polypeptide by contacting the melanophore cells which comprise the receptor with both the receptor ligand and a test compound to be screened. Inhibition of the signal generated by the ligand indicates that a test compound is a potential antagonist for the receptor, i. e. , inhibits activation of the receptor.
• the screen may be employed for identifying a test compound which activates the receptor by contacting such cells with compounds to be screened and determining whether each test compound generates a signal, i.e., activates the receptor.
• screening techniques include the use of cells which express a human RTA- like-GPCR polypeptide (for example, transfected CHO cells) in a system which measures extracellular pH changes caused by receptor activation (see, e.g., Science
• test compounds may be contacted with a cell which expresses a human RTA-like-GPCR polypeptide and a second messenger response, e.g., signal transduction or pH changes, can be measured to determine whether the test compound activates or inhibits the receptor.
• a second messenger response e.g., signal transduction or pH changes
• Another such screening technique involves introducing RNA encoding a human RTA-like-GPCR polypeptide into Xenopus oocytes to transiently express the receptor.
• the transfected oocytes can then be contacted with the receptor ligand and a test compound to be screened, followed by detection of inliibition or activation of a calcium signal in the case of screening for test compounds which are thought to inhibit activation of the receptor.
• Another screening technique involves expressing a human RTA-like-GPCR polypeptide in cells in which the receptor is linked to a phospholipase C or D.
• Such cells include endothelial cells, smooth muscle cells, embryonic kidney cells, etc.
• the screening may be accomplished as described above by quantifying the degree of activation of the receptor from changes in the phospholipase activity.
• test compounds which increase or decrease RTA-like-GPCR gene expression are identified.
• An RTA-like-GPCR polynucleotide is contacted with a test compound, and the expression of an RNA or polypeptide product of the RTA- like-GPCR polynucleotide is determined.
• the level of expression of appropriate mRNA or polypeptide in the presence of the test compound is compared to the level of expression of mRNA or polypeptide in the absence of the test compound.
• the test compound can then be identified as a modulator of expression based on this comparison. For example, when expression of mRNA or polypeptide is greater in the presence of the test compound than in its absence, the test compound is identified as a stimulator or enhancer of the mRNA or polypeptide expression. Alternatively, when expression of the mRNA or polypeptide is less in the presence of the test compound than in its absence, the test compound is identified as an inhibitor of the mRNA or polypeptide expression.
• the level of RTA-like-GPCR mRNA or polypeptide expression in the cells can be determined by methods well known in the art for detecting mRNA or polypeptide. Either qualitative or quantitative methods can be used.
• the presence of polypeptide products of an RTA-like-GPCR polynucleotide can be determined, for example, using a variety of techniques known in the art, including immunochemical methods such as radioimmunoassay, Western blotting, and immunohistochemistry.
• polypeptide synthesis can be determined in vivo, in a cell culture, or in an in vitro translation system by detecting incorporation of labeled amino acids into an RTA-like-GPCR polypeptide.
• Such screening can be carried out either in a cell-free assay system or in an intact cell.
• Any cell which expresses an RTA-like-GPCR polynucleotide can be used in a cell-based assay system.
• the RTA-like-GPCR polynucleotide can be naturally occurring in the cell or can be introduced using techniques such as those described above.
• Either a primary culture or an established cell line, such as CHO or human embryonic kidney 293 cells, can be used.
• compositions of the invention can comprise, for example, an RTA-like-GPCR polypeptide, RTA-like- GPCR polynucleotide, antibodies which specifically bind to an RTA-like-GPCR polypeptide, or mimetics, agonists, antagonists, or inhibitors of an RTA-like-GPCR polypeptide activity.
• the compositions can be administered alone or in combination with at least one other agent, such as stabilizing compound, which can be administered in any sterile, biocompatible pharmaceutical carrier, including, but not limited to, saline, buffered saline, dextrose, and water.
• the compositions can be administered to a patient alone, or in combination with other agents, drugs or hormones.
• compositions of the invention can be administered by any number of routes including, but not limited to, oral, intravenous, intramuscular, intra-arterial, intramedullary, intrathecal, intraventricular, transdermal, subcutaneous, intraperitoneal, intranasal, parenteral, topical, sublingual, or rectal means.
• Pharmaceutical compositions for oral administration can be formulated using pharmaceutically acceptable carriers well known in the art in dosages suitable for oral administration.
• Such carriers enable the pharmaceutical compositions to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions, and the like, for ingestion by the patient.
• Pharmaceutical preparations for oral use can be obtained through combination of active compounds with solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores.
• Suitable excipients are carbohydrate or protein fillers, such as sugars, including lactose, sucrose, mannitol, or sorbitol; starch from corn, wheat, rice, potato, or other plants; cellulose, such as methyl cellulose, hydroxy- propylmethyl-cellulose, or sodium carboxymethylcellulose; gums including arabic and tragacanth; and proteins such as gelatin and collagen.
• disintegrating or solubilizing agents can be added, such as the cross-linked polyvinyl pynolidone, agar, alginic acid, or a salt thereof, such as sodium alginate.
• Dragee cores can be used in conjunction with suitable coatings, such as concentrated sugar solutions, which also can contain gum arabic, talc, polyvinylpyrrolidone, carbopol gel, polyethylene glycol, and or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures.
• suitable coatings such as concentrated sugar solutions, which also can contain gum arabic, talc, polyvinylpyrrolidone, carbopol gel, polyethylene glycol, and or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures.
• Dyestuffs or pigments can be added to the tablets or dragee coatings for product identification or to characterize the quantity of active compound, i.e., dosage.
• Push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a coating, such as glycerol or sorbitol.
• Push-fit capsules can contain active ingredients mixed with a filler or binders, such as lactose or starches, lubricants, such as talc or magnesium stearate, and, optionally, stabilizers.
• the active compounds can be dissolved or suspended in suitable liquids, such as fatty oils, liquid, or liquid polyethylene glycol with or without stabilizers.
• compositions suitable for parenteral administration can be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks' solution, Ringer's solution, or physiologically buffered saline.
• Aqueous injection suspensions can contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran.
• sus- pensions of the active compounds can be prepared as appropriate oily injection suspensions.
• Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or liposomes.
• Non-lipid polycationic amino polymers also can be used for delivery.
• the suspension also can contain suitable stabilizers or agents which increase the solubility of the compounds to allow for the preparation of highly concentrated solutions.
• penetrants appropriate to the particular barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.
• compositions of the present invention can be manufactured in a manner that is known in the art, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping, or lyophilizing processes.
• the pharmaceutical composition can be provided as a salt and can be formed with many acids, including but not limited to, hydrochloric, sulfuric, acetic, lactic, tartaric, malic, succinic, etc. Salts tend to be more soluble in aqueous or other protonic solvents than are the conesponding free base forms.
• the prefened preparation can be a lyophilized powder which can contain any or all of the following: 1-50 mM histidine, 0.1%-2% sucrose, and 2-7% mannitol, at a pH range of 4.5 to 5.5, that is combined with buffer prior to use.
• compositions After pharmaceutical compositions have been prepared, they can be placed in an appropriate container and labeled for treatment of an indicated condition. Such labeling would include amount, frequency, and method of administration.
• GPCRs are ubiquitous in the mammalian host and are responsible for many biological functions, including many pathologies. Accordingly, it is desirable to find compounds and drugs which stimulate a GPCR on the one hand and which can inhibit the function of a GPCR on the other hand.
• compounds which activate a GPCR may be employed for therapeutic purposes, such as the treatment of asthma, Parkinson's disease, acute heart failure, urinary retention, and osteoporosis.
• compounds which activate GPCRs are useful in treating various cardiovascular ailments such as caused by the lack of pulmonary blood flow or hypertension.
• these compounds may also be " used in treating various physiological disorders relating to abnormal control of fluid and electrolyte homeostasis and in diseases associated with abnormal angiotensin-induced aldosterone secretion.
• compounds which inhibit activation of a GPCR can be used for a variety of therapeutic purposes, for example, for the treatment of hypotension and/or hypertension, angina pectoris, myocardial infarction, ulcers, asthma, allergies, benign prostatic hypertrophy, and psychotic and neurological disorders including schizophrenia, manic excitement, depression, delirium, dementia or severe mental retardation, dyskinesias, such as Huntington's disease or Tourett's syndrome, among others.
• Compounds which inhibit GPCRs also are useful in reversing endogenous anorexia, in the control of bulimia, and in treating various cardiovascular ailments such as caused by excessive pulmonary blood flow or hypotension.
• test compound identified as described herein in an appropriate animal model.
• an agent identified as described herein e.g., a modulating agent, an antisense nucleic acid molecule, a specific antibody, ribozyme, or an RTA-like-
• GPCR polypeptide binding molecule can be used in an animal model to determine the efficacy, toxicity, or side effects of treatment with such an agent.
• an agent identified as described herein can be used in an animal model to determine the mechanism of action of such an agent.
• this invention pertains to uses of novel agents identified by the above-described screening assays for treatments as described herein.
• a reagent which affects RTA-like-GPCR activity can be administered to a human cell, either in vitro or in vivo, to reduce RTA-like-GPCR activity.
• the reagent preferably binds to an expression product of a human RTA-like-GPCR gene. If the expression product is a protein, the reagent is preferably an antibody.
• an antibody can be added to a preparation of stem cells which have been removed from the body. The cells can then be replaced in the same or another human body, with or without clonal propagation, as is known in the art.
• the reagent is delivered using a liposome.
• the liposome is stable in the animal into which it has been administered for at least about 30 minutes, more preferably for at least about 1 hour, and even more preferably for at least about 24 hours.
• a liposome comprises a lipid composition that is capable of targeting a reagent, particularly a polynucleotide, to a particular site in an animal, such as a human.
• the lipid composition of the liposome is capable of targeting to a specific organ of an animal, such as the lung, liver, spleen, heart brain, lymph nodes, and skin.
• a liposome useful in the present invention comprises a lipid composition that is capable of fusing with the plasma membrane of the targeted cell to deliver its contents to the cell.
• the transfection efficiency of a liposome is about 0.5 ⁇ g of DNA per 16 nmole of liposome delivered to about 10 6 cells, more preferably about 1.0 ⁇ g of DNA per 16 nmole of liposome delivered to about 10 6 cells, and even more preferably about 2.0 ⁇ g of DNA per 16 nmol of liposome delivered to about 10 6 cells.
• a liposome is between about 100 and 500 nm, more preferably between about 150 and 450 nm, and even more preferably between about 200 and 400 nm in diameter.
• Suitable liposomes for use in the present invention include those liposomes standardly used in, for example, gene delivery methods known to those of skill in the art. More prefened liposomes include liposomes having a polycationic lipid composition and/or liposomes having a cholesterol backbone conjugated to polyethylene glycol.
• a liposome comprises a compound capable of targeting the liposome to a tumor cell, such as a tumor cell ligand exposed on the outer surface of the liposome.
• a liposome with a reagent such as an antisense oligonucleotide or ribozyme can be achieved using methods which are standard in the art (see, for example, U.S. Patent 5,705,151).
• a reagent such as an antisense oligonucleotide or ribozyme
• from about 0.1 ⁇ g to about 10 ⁇ g of polynucleotide is combined with about 8 nmol of liposomes, more preferably from about 0.5 ⁇ g to about 5 ⁇ g of polynucleotides are combined with about 8 nmol liposomes, and even more preferably about 1.0 ⁇ g of polynucleotides is combined with about 8 nmol liposomes.
• antibodies can be delivered to specific tissues in vivo using receptor-mediated targeted delivery.
• Receptor-mediated DNA delivery techniques are taught in, for example, Findeis et al. Trends in Biotechnol. 11, 202-05 (1993); Chiou et al, GENE THERAPEUTICS: METHODS AND APPLICATIONS OF DIRECT GENE TRANSFER (J.A. Wolff, ed.) (1994); Wu & Wu, J. Biol. Chem. 263, 621-24 (1988); Wu et al, J. Biol. Chem. 269, 542-46 (1994); Zenke et al, Proc. Natl. Acad. Sci.
• a therapeutically effective dose refers to that amount of active ingredient which increases or decreases RTA-like-GPCR activity relative to the RTA-like-GPCR activity which occurs in the absence of the therapeutically effective dose.
• the therapeutically effective dose can be estimated initially either in cell culture assays or in animal models, usually mice, rabbits, dogs, or pigs.
• the animal model also can 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.
• Therapeutic efficacy and toxicity e.g., ED 50 (the dose therapeutically effective in 50% of the population) and LD 50 (the dose lethal to 50% of the population), can be determined by standard pharmaceutical procedures in cell cultures or experimental animals.
• the dose ratio of toxic to therapeutic effects is the therapeutic index, and it can be expressed as the ratio, LD 50 /ED 50 .
• compositions which exhibit large therapeutic indices are preferred.
• the data obtained from cell culture assays and animal studies is used in formulating a range of dosage for human use.
• the dosage contained in such compositions is preferably within a range of circulating concentrations that include the ED 50 with little or no toxicity.
• the dosage varies within this range depending upon the dosage form employed, sensitivity of the patient, and the route of administration.
• the exact dosage will be determined by the practitioner, in light of factors related to the subject that requires treatment. Dosage and administration are adjusted to provide sufficient levels of the active ingredient or to maintain the desired effect. Factors which can be taken into account include the severity of the disease state, general health of the subject, age, weight, and gender of the subject, diet, time and frequency of administration, drug combination(s), reaction sensitivities, and tolerance/response to therapy. Long-acting pharmaceutical compositions can be administered every 3 to 4 days, every week, or once every two weeks depending on the half-life and clearance rate of the particular formulation.
• Normal dosage amounts can vary from 0.1 to 100,000 micrograms, up to a total dose of about 1 g, depending upon the route of administration.
• Guidance as to particular dosages and methods of delivery is provided in the literature and generally available to practitioners in the art. Those skilled in the art will employ different formulations for nucleotides than for proteins or their inhibitors. Similarly, delivery of polynucleotides or polypeptides will be specific to particular cells, conditions, locations, etc.
• polynucleotides encoding the antibody can be constructed and introduced into a cell either ex vivo or in vivo using well- established techniques including, but not limited to, transferrin-polycation-mediated DNA transfer, transfection with naked or encapsulated nucleic acids, liposome- mediated cellular fusion, intracellular transportation of DNA-coated latex beads, protoplast fusion, viral infection, electroporation, "gene gun,” and DEAE- or calcium phosphate-mediated transfection.
• Effective in vivo dosages of an antibody are in the range of about 5 ⁇ g to about
• effective in vivo dosages are in the range of about 100 ng to about 200 ng, 500 ng to about 50 mg, about 1 ⁇ g to about 2 mg, about 5 ⁇ g to about 500 ⁇ g, and about 20 ⁇ g to about
• the reagent is preferably an antisense oligonucleotide or a ribozyme.
• Polynucleotides which express antisense oligo- nucleotides or ribozymes can be introduced into cells by a variety of methods, as described above.
• a reagent reduces expression of an RTA-like-GPCR gene or the activity of an RTA-like-GPCR polypeptide by at least about 10, preferably about 50, more preferably about 75, 90, or 100% relative to the absence of the reagent. The effectiveness of the mechanism chosen to decrease the level of expression of an RTA-like-GPCR gene or the activity of an RTA-like-GPCR polypeptide by at least about 10, preferably about 50, more preferably about 75, 90, or 100% relative to the absence of the reagent. The effectiveness of the mechanism chosen to decrease the level of expression of an RTA-like-GPCR gene or the activity of an RTA-like-GPCR polypeptide by at least about 10, preferably about 50, more
• RTA-like-GPCR gene or the activity of an RTA-like-GPCR polypeptide can be assessed using methods well known in the art, such as hybridization of nucleotide probes to RTA-like-GPCR-specific mRNA, quantitative RT-PCR, immunologic detection of an RTA-like-GPCR polypeptide, or measurement of RTA-like-GPCR activity.
• any of the phannaceutical compositions of the invention can be administered in combination with other appropriate therapeutic agents.
• Selection of the appropriate agents for use in combination therapy can be made by one of ordinary skill in the art, according to conventional pharmaceutical principles.
• the combination of therapeutic agents can act syner- gistically to effect the treatment or prevention of the various disorders described above. Using this approach, one may be able to achieve therapeutic efficacy with lower dosages of each agent, thus reducing the potential for adverse side effects.
• any of the therapeutic methods described above can be applied to any subject in need of such therapy, including, for example, mammals such as dogs, cats, cows, horses, rabbits, monkeys, and most preferably, humans.
• GPCRs also can be used in diagnostic assays for detecting diseases and abnormalities or susceptibility to diseases and abnormalities related to the presence of mutations in the nucleic acid sequences which encode a GPCR.
• diseases are related to cell transformation, such as tumors and cancers, and various cardiovascular disorders, including hypertension and hypotension, as well as diseases arising from abnormal blood flow, abnormal angiotensin-induced aldosterone secretion, and other abnormal control of fluid and electrolyte homeostasis.
• Differences can be determined between the cDNA or genomic sequence encoding a GPCR in individuals afflicted with a disease and in normal individuals. If a mutation is observed in some or all of the afflicted individuals but not in normal individuals, then the mutation is likely to be the causative agent of the disease.
• Sequence differences between a reference gene and a gene having mutations can be revealed by the direct DNA sequencing method.
• cloned DNA segments can be employed as probes to detect specific DNA segments.- The sensitivity of this method is greatly enhanced when combined with PCR.
• a sequencing primer can be used with a double-stranded PCR product or a single-stranded template molecule generated by a modified PCR.
• the sequence determination is performed by conventional procedures using radio labeled nucleotides or by automatic sequencing procedures using fluorescent tags.
• DNA sequence differences can be carried out by detection of alteration in electrophoretic mobility of DNA fragments in gels with or without denaturing agents. Small sequence deletions and insertions can be visualized, for example, by high resolution gel electrophoresis. DNA fragments of different sequences can be distinguished on denaturing formamide gradient gels in which the mobilities of different DNA fragments are retarded in the gel at different positions according to their specific melting or partial melting temperatures (see, e.g., Myers et al, Science 230, 1242, 1985). Sequence changes at specific locations can also be revealed by nuclease protection assays, such as RNase and S 1 protection or the chemical cleavage method (e.g., Cotton et al, Proc. Natl.
• the detection of a specific DNA sequence can be performed by methods such as hybridization, RNase protection, chemical cleavage, direct DNA sequencing or the use of restriction enzymes and Southern blotting of genomic DNA.
• direct methods such as gel-electrophoresis and DNA sequencing, mutations can also be detected by in situ analysis.
• Altered levels of a GPCR also can be detected in various tissues.
• Assays used to detect levels of the receptor polypeptides in a body sample, such as blood or a tissue biopsy, derived from a host are well known to those of skill in the art and include radioimmunoassays, competitive binding assays, Western blot analysis, and ELISA assays.
• the polynucleotide of SEQ ID NO: 1 is inserted into the expression vector pCEV4 and the expression vector pCEV4-RTA-like-GPCR polypeptide obtained is transfected into human embryonic kidney 293 cells.
• the cells are scraped from a culture flask into 5 ml of Tris HCl, 5 mM EDTA, pH 7.5, and lysed by sonication. Cell lysates are centrifuged at 1000 rpm for 5 minutes at 4 °C. The supernatant is centrifuged at 30,000 x g for 20 minutes at 4 °C.
• the pellet is suspended in binding buffer containing 50 mM Tris HCl, 5 mM MgSO 4 , 1 mM EDTA, 100 mM NaCl, pH 7.5, supplemented with 0.1 % BSA, 2 ⁇ g/ml aprotinin, 0.5 mg/ml leupeptin, and 10 ⁇ g/ml phosphoramidon.
• Optimal membrane suspension dilutions defined as the protein concentration required to bind less than 10 % of an added radioligand, i.e. 125 I-labeled RTA, are added to 96-well polypropylene microtiter plates containing ligand, non-labeled peptides, and binding buffer to a final volume of 250 ⁇ l.
• membrane preparations are incubated in the presence of increasing concentrations (0.1 nM to 4 nM) of 125 I ligand.
• Binding reaction mixtures are incubated for one hour at 30 °C. The reaction is stopped by filtration through GF/B filters treated with 0.5% polyethyleneimine, using a cell harvester. Radioactivity is measured by scintillation counting, and data are analyzed by a computerized non-linear regression program. Non-specific binding is defined as the amount of radioactivity remaining after incubation of membrane protein in the presence of 100 nM of unlabeled peptide. Protein concentration is measured by the Bradford method using Bio-Rad Reagent, with bovine serum albumin as a standard. The RTA-like-GPCR activity of the polypeptide comprising the amino acid sequence of SEQ ID NO: 2 is demonstrated. EXAMPLE 2
• Human embryonic kidney 293 cells transfected with a polynucleotide which expresses human RTA-like-GPCR are scraped from a culture flask into 5 ml of Tris HCl, 5 mM EDTA, pH 7.5, and lysed by sonication. Cell lysates are centrifuged at 1000 rpm for 5 minutes at 4 °C. The supernatant is centrifuged at 30,000 x g for 20 minutes at 4 °C. The pellet is suspended in binding buffer containing 50 mM Tris HCl, 5 mM MgSO 4 , 1 mM EDTA, 100 mM NaCl, pH 7.5, supplemented with 0.1 %
• Optimal membrane suspension dilutions defined as the protein concentration required to bind less than 10% of the added radioligand, i.e. RTA, are added to 96-
• Binding reaction mixtures are incubated for one hour at 30 °C.
• the reaction is stopped by filtration through GF/B filters treated with 0.5% polyethyleneimine, using a cell harvester. Radioactivity is measured by scintillation counting, and data are analyzed by a computerized non-linear regression program.
• Non-specific binding is defined as the amount of radioactivity remaining after incubation of membrane protein in the presence of 100 nM of unlabeled peptide.
• test compound which increases the radioactivity of membrane protein by at least 15% relative to radioactivity of membrane protein which was not incubated with a test compound is identified as a compound which binds to a human RTA-like-GPCR polypeptide.
• Receptor-mediated inhibition of cAMP formation can be assayed in host cells which express human RTA-like-GPCR.
• Cells are plated in 96-well-pIates and incubated in Dulbecco's phosphate buffered saline (PBS) supplemented with 10 mM HEPES, 5 mM theophylline, 2 ⁇ g/ml aprotinin, 0.5 mg/ml leupeptin, and 10 ⁇ g/ml phos- phoramidon for 20 minutes at 37 °C in 5% CO 2 .
• a test compound is added and incubated for an additional 10 minutes at 37 °C.
• the medium is aspirated, and the reaction is stopped by the addition of 100 mM HCl.
• the plates are stored at 4 °C for 15 minutes.
• cAMP content in the stopping solution is measured by radio- immunoassay.
• Radioactivity is quantified using a gamma counter equipped with data reduction software.
• a test compound which decreases radioactivity of the contents of a well relative to radioactivity of the contents of a well in the absence of the test compound is identified as a potential inhibitor of cAMP formation.
• a test compound which increases radioactivity of the contents of a well relative to radioactivity of the contents of a well in the absence of the test compound is identified as a potential enhancer of cAMP formation.
• Intracellular free calcium concentration can be measured by microspecfrofluorometry using the fluorescent indicator dye Fura-2/AM (Bush et al, J. Neurochem. 57, 562- 74, 1991).
• Stably transfected cells are seeded onto a 35 mm culture dish containing a glass coverslip insert. Cells are washed with HBS , incubated with a test compound, and loaded with 100 ⁇ l of Fura-2/AM (10 ⁇ M) for 20-40 minutes. After washing with HBS to remove the Fura-2/AM solution, cells are equilibrated in HBS for
• Fluorescence emission is determined at 510 nM, with excitation wavelengths alternating between 340 nM and 380 nM.
• Raw fluorescence data are converted to calcium concentrations using standard calcium concentration curves and software analysis techniques.
• a test compound which increases the fluorescence by at least 15% relative to fluorescence in the absence of a test compound is identified as a compound which mobilizes intracellular calcium.
• Cells which stably express human RTA-like-GPCR cDNA are plated in 96-well plates and grown to confluence. The day before the assay, the growth medium is changed to 100 ⁇ l of medium containing 1% serum and 0.5 ⁇ Ci 3 H-myinositol. The plates are incubated overnight in a CO 2 incubator (5% CO 2 at 37 °C). Immediately before the assay, the medium is removed and replaced by 200 ⁇ l of PBS containing 10 mM LiCl, and the cells are equilibrated with the new medium for 20 minutes. During this interval, cells also are equilibrated with antagonist, added as a 10 ⁇ l aliquot of a 20-fold concentrated solution in PBS.
• the 3 H-inositol phosphate accumulation from inositol phospholipid metabolism is started by adding 10 ⁇ l of a solution containing a test compound. To the first well 10 ⁇ l are added to measure basal accumulation. Eleven different concentrations of test compound are assayed in the following 11 wells of each plate row. All assays are performed in duplicate by repeating the same additions in two consecutive plate rows.
• the plates are incubated in a CO 2 incubator for one hour. The reaction is terminated by adding 15 ⁇ l of 50% v/v trichloroacetic acid (TCA), followed by a 40 minute incubation at 4 °C. After neutralizing TCA with 40 ⁇ l of 1 M Tris, the content of the wells is transfened to a Multiscreen HV filter plate (Millipore) containing Dowex AG1-X8 (200-400 mesh, formate form). The filter plates are prepared by adding 200 ⁇ l of Dowex AG1-X8 suspension (50% v/v, water:resin) to each well. The filter plates are placed on a vacuum manifold to wash or elute the resin bed. Each well is washed 2 times with 200 ⁇ l of water, followed by 2 x 200 ⁇ l of 5 mM sodium tetraborate/60 mM ammonium formate.
• TCA 50% v/v trichloroacetic acid
• the 3 H-IPs are eluted into empty 96-well plates with 200 ⁇ l of 1.2 M ammonium formate/0.1 formic acid.
• the content of the wells is added to 3 ml of scintillation cocktail, and radioactivity is determined by liquid scintillation counting.
• Binding assays are carried out in a binding buffer containing 50 mM HEPES, pH 7.4, 0.5% BSA, and 5 mM MgCl 2 .
• the standard assay for radioligand binding to membrane fragments comprising RTA-like-GPCR polypeptides is carried out as follows in 96 well microtiter plates (e.g., Dynatech Immulon II Removawell plates). Radioligand is diluted in binding bufferf- PMSF/Baci to the desired cpm per 50 ⁇ l, then 50 ⁇ l aliquots are added to the wells. For non-specific binding samples, 5 ⁇ l of 40 ⁇ M cold ligand also is added per well.
• Binding is initiated by adding 150 ⁇ l per well of membrane diluted to the desired concentration (10-30 ⁇ g membrane protein/well) in binding buffer+ PMSF/Baci. Plates are then covered with Linbro mylar plate sealers (Flow Labs) and placed on a Dynatech Microshaker II. Binding is allowed to proceed at room temperature for 1-2 hours and is stopped by centrifuging the plate for 15 minutes at 2,000 x g. The supernatants are decanted, and the membrane pellets are washed once by addition of
• binding assays to obtain membrane pellets for studies on solubilization of recepto ⁇ ligand complex and for receptor purification are also carried out. These are identical to the standard assays except that (a) binding is carried out in polypropylene tubes in volumes from 1-250 ml, (b) concentration of membrane protein is always 0.5 mg/ml, and (c) for receptor purification, BSA concentration in the binding buffer is reduced to 0.25%, and the wash step is done with binding buffer without BSA, which reduces
• membrane pellets are resuspended in 200 ⁇ l per microtiter plate well of ice-cold binding buffer without BSA. Then 5 ⁇ l per well of 4 mM N-5-azido-2-nitrobenzoyloxysuccinimide (ANB- NOS, Pierce) in DMSO is added and mixed. The samples are held on ice and UV- hradiated for 10 minutes with a Mineralight R-52G lamp (UVP Inc., San Gabriel, Calif.) at a distance of 5-10 cm.
• ANB- NOS N-5-azido-2-nitrobenzoyloxysuccinimide
• Membrane solubilization is carried out in buffer containing 25 mM Tris , pH 8, 10% glycerol (w/v) and 0.2 mM CaCl (solubilization buffer).
• the highly soluble detergents including Triton X-100, deoxycholate, deoxycholate ysolecithin, CHAPS, and zwittergent are made up in solubilization buffer at 10% concentrations and stored as frozen aliquots. Lysolecithin is made up fresh because of insolubility upon freeze- thawing and digitonin is made fresh at lower concentrations due to its more limited solubility.
• washed pellets after the binding step are resuspended free of visible particles by pipetting and vortexing in solubilization buffer at 100,000 x g for 30 minutes. The supernatants are removed and held on ice and the pellets are discarded.
• the intact R:L complex can be assayed by four different methods. All are carried out on ice or in a cold room at 4-10 °C).
• Binding of biotinyl-receptor to GH 4 Cl membranes is carried out as described above.
• Incubations are for 1 hour at room temperature.
• the binding incubations contain 10 nM Bio-S29. 1 5 I ligand is added as a tracer at levels of 5,000-100,000 cpm per mg of membrane protein.
• Control incubations contain 10 ⁇ M cold ligand to saturate the receptor with non-biotinylated ligand.
• Solubilization of receptor :ligand complex also is carried out as described above, with 0.15% deoxycholate ysolecithin in solubilization buffer containing 0.2 mM MgCl 2 , to obtain 100,000 x g supernatants containing solubilized R:L complex.
• SA-agarose Chemical Co.; "SA-agarose”
• solubilization buffer is added to the solubilized membranes as 1/30 of the final volume. This mixture is incubated with constant stirring by end-over-end rotation for 4-5 hours at 4-10 °C. Then the mixture is applied to a column and the non-bound material is washed through. Binding of radioligand to SA-agarose is determined by comparing cpm in the 100,000 x g supernatant with that in the column effluent after adsorption to SA-agarose. Finally, the column is washed with 12-15 column volumes of solubilization buffer+0.15% deoxycholate ysolecithin +1/500 (vol vol) 100 x 4pase.
• streptavidin column is eluted with solubilization buffer+0.1 mM EDTA+0.1 mM
• Eluates from the streptavidin column are incubated overnight (12-15 hours) with immobilized wheat germ agglutinin (WGA agarose, Vector Labs) to adsorb the receptor via interaction of covalently bound carbohydrate with the WGA lectin.
• the ratio (vol/vol) of WGA-agarose to streptavidin column eluate is generally 1:400. A range from 1:1000 to 1:200 also can be used.
• the resin is pelleted by centrifugation, the supernatant is removed and saved, and the resin is washed 3 times (about 2 minutes each) in buffer containing 50 mM HEPES, pH 8, 5 mM MgCl 2 ⁇ and 0.15% deoxycholatedysolecithin.
• the resin is extracted three times by repeated mixing (vortex mixer on low speed) over a 15-30 minute period on ice, with 3 resin columns each time, of 10 mM N-N'-N"-triacetylchitotriose in the same HEPES buffer used to wash the resin. After each elution step, the resin is centrifuged down and the supernatant is carefully removed, free of WGA-agarose pellets. The three, pooled eluates contain the final, purified receptor.
• the material non-bound to WGA contain G protein subunits specifically eluted from the streptavidin column, as well as non-specific contaminants. All these fractions are stored frozen at -90 °C.
• RTA-like-GPCR polypeptides comprising a glutathione-S-transferase protein and absorbed onto glutathione-derivatized wells of 96-well microtiter plates are contacted with test compounds from a small molecule library at pH 7.0 in a physiological buffer solution.
• RTA-like-GPCR polypeptides comprise an amino acid sequence shown in SEQ ID NO:2.
• the test compounds comprise a fluorescent tag. The samples are incubated for 5 minutes to one hour. Control samples are incubated in the absence of a test compound.
• the buffer solution containing the test compounds is washed from the wells. Binding of a test compound to an RTA-like-GPCR polypeptide is detected by fluorescence measurements of the contents of the wells. A test compound which increases the fluorescence in a well by at least 15% relative to fluorescence of a well in which a test compound was not incubated is identified as a compound which binds to an RTA-like-GPCR polypeptide.
• test compound is administered to a culture of human gastric cells and incubated at
• RNA is isolated from the two cultures as described in Chirgwin et al, Biochem. 18, 5294-99, 1979).
• Northern blots are prepared using 20 to 30 ⁇ g total RNA and hybridized with a 32 P-labeled RTA-like-GPCR-specific probe at 65 ° C in Express- hyb (CLONTECH).
• the probe comprises at least 11 contiguous nucleotides selected from the complement of SEQ ID NO:l.
• a test compound which decreases the RTA- like-GPCR-specific signal relative to the signal obtained in the absence of the test compound is identified as an inhibitor of RTA-like-GPCR gene expression.
• oligonucleotides comprising at least 11 contiguous nucleotides selected from the complement of SEQ ID NO:l are synthesized on a Pharmacia Gene Assembler series synthesizer using the phosphoramidite procedure (Uhlmann et al, Chem. Rev. 90, 534-83, 1990). Following assembly and deprotection, oligonucleotides are ethanol-precipitated twice, dried, and suspended in phosphate-buffered saline (PBS) at the desired concentration. Purity of these oligonucleotides is tested by capillary gel electrophoreses and ion exchange HPLC. Endotoxin levels in the oligonucleotide preparation are determined using the Limulus Amebocyte Assay (Bang, Biol. Bull. (Woods Hole, Mass.) 105, 361-362, 1953).
• the antisense oligonucleotides are administered to a patient with a breast tumor.
• the size of the patient's breast tumor is decreased.

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