METHODS AND REAGENTS FOR DISCOVERING AND USING MAMMALIAN MELANOCORTIN RECEPTOR AGONISTS AND ANTAGONISTS TO MODULATE FEEDING BEHAVIOR IN ANIMALS

Abstract: The present invention provides recombinant expression constructs comprising nucleic acid encoding mammalian melanocortin receptors, and mammalian cells into which said recombinant expression constructs have been introduced that express functional mammalian melanocortin receptors. The invention provides a panel of such transformed mammalian cells expressing melanocortin receptors for screening compounds for receptor agonist and antagonist activity. The invention also provides methods for using such panels of melanocortin receptor-expressing mammalian cells to specifically detect and identify agonists and antagonists for each melanocortin receptor, as well as patterns of agonist and antagonist activity of said compounds for the class of melanocortin receptors. Such screening methods provide a means for identifying compounds with patterns of melanocortin agonist and antagonist activity which is associated with the capacity to influence or modify metabolism and behavior, particularly feeding behavior.

Description: METHODS AND REAGENTS FOR DISCOVERING AND USING MAMMALIAN MELANOCORTIN RECEPTOR AGONISTS AND ANTAGONISTS TO MODULATE FEEDING BEHAVIOR IN ANIMALS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the cloning, expression and functional characterization of mammalian melanocortin receptor genes. The invention provides nucleic acid encoding mammalian melanocortin receptors, recombinant expression constructs comprising said nucleic acid, and mammalian cells into which said recombinant expression constructs have been introduced, and that express functional mammalian melanocortin receptors. The invention also provides a panel of such transformed mammalian cells expressing melanocortin receptors for screening compounds for receptor agonist and antagonist activity. The invention provides methods for using such panels of melanocortin receptor-expressing mammalian cells to specifically detect and identify agonists and antagonists for each melanocortin receptor, as well as patterns of agonist and antagonist activity of said compounds for the class of melanocortin receptors. Such screening methods provide a means for identifying compounds with patterns of melanocortin agonist and antagonist activity which is associated with the capacity to influence or modify physiological function and behavior, particularly metabolism and feeding behavior. 2. Background of the Invention The proopiomelanocortin (POMC) gene product is processed to produce a large number of biologically active peptides. Two of these peptides, α-melanocyte stimulating hormone (αMSH), and adrenocorticotropic hormone (ACTH) have well understood roles in control of melanocyte and adrenocortical function, respectively. Both of these hormones are also found in a variety of forms with unknown functions, for example, γ- melanocyte stimulating hormone (γMSH), which has little or no ability to stimulate pigmentation (Ling et al., 1979, Life Sci.21- 1773-1780; Slominski et al., 1992, Life Sci. 50: 1103-1108). A melanocortin receptor gene specific for each of the αMSH, ACTH and γMSH hormones has been discovered by some of the present inventors (see U.S. Patent Nos. 5,280,112, 5,532,347 and U.S. Application Serial No. 08/044,812, incorporated by reference herein). In addition, two other melanocortin receptor genes have been discovered by some of the present inventors (see Lu et al, 1994, Nature 371 : 799-802; Mountjoy et al, 1994, Molec. Endocrinol. £: 1298-1308) and others (see Gantz et al., 1993, J. Biol. Chem. 2_S: 15174-15179 and Labbe et al., 1994, Biochem. 33.: 4543-4549). Along with the well-recognized activities of αMSH in melanocytes and ACTH in adrenal and pituitary glands, the melanocortin peptides also have a diverse array of biological activities in other tissues, including the brain and immune system, and bind to specific receptors in these tissues with a distinct pharmacology (see, Hanneman et al, in Peptide Hormone as Prohormones, G. Martinez, ed. (Ellis Horwood Ltd.: Chichester, UK) pp. 53-82; DeWied & Jolies, 1982, Physiol. Rev. 62: 976-1059 for reviews). A complete understanding of these peptides and their diverse biological activities requires the isolation and characterization of their corresponding receptors. Some biochemical studies have been reported in the prior art. Shimuze, 1985, Yale J. Biol. Med. 5_8: 561-570 discusses the physiology of melanocyte stimulating hormone. Tatro & Reichlin, 1987, Endocrinology _2\ : 1900-1907 disclose that MSH receptors are widely distributed in rodent tissues. Solaetα/., 1989,J. Biol. Chem. 264: 14277-14280 disclose the molecular weight characterization of mouse and human MSH receptors linked to radioactively and photoaffinity labeled MSH analogues. Siegrist et al., 1991, J. Receptor Res. _λ_: 323-331 disclose the quantification of receptors on mouse melanoma tissue by receptor autoradiography. Cone & Mountjoy, U.S. Patent No. 5,532,347 disclose the isolation of human and mouse α-MSH receptor genes and uses thereof (incorporated herein by reference). Cone & Mountjoy, U.S. Patent No. 5,280,112 disclose the isolation of human and bovine ACTH receptor genes and uses thereof (incorporated herein by reference). Mountjoy et al., 1992, Science 257: 1248-1251 disclose the isolation of cDNAs encoding mammalian ACTH and MSH receptor proteins. POMC neurons are present in only two regions of the brain, the arcuate nucleus of the hypothalamus, and the nucleus of the solitary tract of the brain stem. Neurons from both sites project to a number of hypothalamic nuclei known to be important in feeding behavior, including the paraventricular nucleus, lateral hypothalamic area, and ventromedial hypothalamic nucleus. While previous reports have claimed both stimulatory and inhibitory effects of α-MSH on feeding behavior (see Shimizu et al., 1989, Life Sci. 45: 543-552; Tsujii et al, 1989, Brian Res. Bull. 23_: 165-169), knowledge of specific melanocortin receptors, their location within the central nervous system and the necessary pharmacological tools were not sufficiently developed at that time to allow the resolution of this issue. The present inventors have shown herein that a novel antagonist of the MC-3 and MC-4 melanocortin receptors can substantially increase food consumption in animals engaged in normal or fast-induced feeding behavior. This is consistent with expression of both MC-3 and MC-4 receptor mRNAs at these sites in in situ hybridization studies (Roselli-Rehfuss et al., 1993, Proc. Natl. Acad. Sci. USA 90: 8856-8860; Mountjoy et al., 1994, Molec. Endocrinol. 8: 1298- 1308). Moreover, the regulation of arcuate nucleus POMC gene expression is consistent with an inhibitory role for POMC in feeding behavior. POMC mRNA levels are decreased following a fast (Bergendahl et al., 1992, Neuroendocrinol. 56.: 913-920; Brady et al., 1990, Neuroendocrinol. _V__: 441-447), and a significant diurnal variation in POMC mRNA levels in the arcuate nucleus is seen in rat, with the nadir occurring around the onset of nighttime feeding at 1800 hrs (Steiner et al, 1994, FASEB J. 8: 479- 488). Thus, the experimental evidence indicates that POMC neurons play an important role in tonic inhibition of feeding behavior, wherein obesity results from a chronic disruption of this inhibitory tone by antagonism of central melanocortin receptors in at least one animal model (agouti). These results reveal for the first time a need in the art for a means for characterizing mammalian melanocortin receptor agonists and antagonists in vitro for the development of compounds that affect feeding behavior in animals. SUMMARY OF THE INVENTION The present invention provides a biological screening system for identifying and characterizing compounds that are agonists or antagonists of mammalian melanocortin receptors. The biological screening system of the invention comprises a panel of transformed mammalian cells comprising a recombinant expression construct encoding a mammalian melanocortin receptor, and expressing said receptor thereby. The invention provides such a panel of transformed mammalian cells wherein the panel comprises cells expressing each type of mammalian melanocortin receptor. Thus, the invention also provides nucleic acid encoding mammalian melanocortin receptors, recombinant expression constructs comprising said nucleic acid, and mammalian cells into which said recombinant expression constructs have been introduced, and that express functional mammalian melanocortin receptors. Methods for using such panels of melanocortin receptor-expressing mammalian cells to specifically detect and identify agonists and antagonists for each melanocortin receptor, as well as patterns of agonist and antagonist activity of said compounds for the class of melanocortin receptors, are also provided. Such screening methods provide a means for identifying compounds with patterns of melanocortin agonist and antagonist activity which is associated with the capacity to influence or modify metabolism and behavior in an animal, particularly feeding behavior. Thus, the invention provides in a first aspect a biological screening panel for determining the melanocortin receptor agonist/antagonist profile of a test compound. The panel comprises a first mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the α-MSH (MC-1) receptor. The panel also comprises a second mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the ACTH (MC-2) receptor. The panel also comprises a third mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-3 receptor. The panel also comprises a fourth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-4 receptor. The panel also comprises a fifth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-5 receptor. As provided by the invention, each mammalian cell expresses the melanocortin receptor encoded by the recombinant expression construct comprising said cell. In preferred embodiments, the melanocortin receptors encoded by the recombinant expression constructs comprising the transformed mammalian cells comprising the panel are mouse MC-1 receptor (SEQ ID Nos.: 3 and 4); human MC-1 receptor (SEQ ID Nos.: 5 and 6), human MC-2 (ACTH) receptor (SEQ ID Nos.: 7 and 8), bovine MC-2 receptor (SEQ ID Nos.: 9 and 10), rat MC-3 receptor (SEQ ID Nos.: 11 and 12), human MC-4 receptor (SEQ ID Nos.: 15 and 16) and mouse MC-5 receptor (SEQ ID Nos.: 17 and 18). In a second aspect, the invention provides a method for using the melanocortin receptor panel to identify and characterize test compounds as melanocortin receptor agonists and/or antagonists. In this embodiment, the method provided by the invention identifies a melanocortin receptor agonist, and comprises the steps of contacting each of the cells of the panel with a test compound to be characterized as an agonist of a mammalian melanocortin receptor and detecting binding of the test compound to each of the mammalian melanocortin receptors by assaying for a metabolite produced in the cells that bind the compound. In a preferred embodiment, the detected metabolite is cAMP. In a preferred embodiment of this method, each of the cells of the panel of mammalian cells expressing mammalian melanocortin receptors further comprises a recombinant expression construct encoding a cyclic AMP responsive element (CRE) transcription factor binding site that is operatively linked to a nucleic acid sequence encoding a protein capable of producing a detectable metabolite. In preferred embodiments, said protein is β-galactosidase, most preferably encoded by a nucleic acid comprising the recombinant expression construct identified as pCRE/β-galactosidase (as disclosed in Chen et al, 1994, Analyt. Biochem. 226: 349-354). As provided by the invention, expression of the protein that produces the detectable metabolite is dependent on binding of the test compound to the melanocortin receptor expressed by each cell in the panel and the intracellular production of cAMP as a result. In this embodiment, cAMP production results in expression of a protein capable of producing a detectable metabolite, the protein most preferably being β-galactosidase. In preferred embodiments, the detectable metabolite absorbs light to produce a colored product. Thus, this embodiment of the invention provides a panel of melanocortin receptor- expressing cells whereby melanocortin hormone binding results in the production of a colored product in proportion to the extent of c AMP production in the cell as a result of hormone receptor binding. In another embodiment of this aspect of the invention is provided a method for characterizing a compound as an antagonist of a mammalian melanocortin receptor. In this embodiment, the method comprises the steps of contacting each of the cells of the panel with an agonist of the mammalian melanocortin receptor in an amount sufficient to produce a detectable amount of a metabolite produced in the cells that bind the agonist, in the presence or absence of a test compound to be characterized as an antagonist of a mammalian melanocortin receptor, and detecting the amount of the metabolite produced in each cell in the panel in the presence of the test compound with the amount of the metabolite produced in each cell in the panel in the absence of the test compound. As provided by the assay, inhibition of the production of the detectable metabolite is used as an indication that the tested compound is a melanocortin receptor antagonist, which is further characterized quantitatively by the extent of said inhibition. In a preferred embodiment of this method, each of the cells of the panel of mammalian cells expressing mammalian melanocortin receptors further comprises a recombinant expression construct encoding a cyclic AMP responsive element (CRE) transcription factor binding site that is operatively linked to a nucleic acid sequence encoding a protein capable of producing a detectable metabolite. In preferred embodiments, said protein is β-galactosidase, most preferably encoded by a nucleic acid comprising the recombinant expression construct identified as pCRE/β-galactosidase. As provided by the invention, expression of the protein that produces the detectable metabolite is dependent on binding of the test compound to the melanocortin receptor expressed by each cell in the panel. In preferred embodiments, the detectable metabolite absorbs light to produce a colored product. Thus, this embodiment of the invention provides a panel of melanocortin receptor-expressing cells whereby melanocortin hormone binding results in the production of a colored product in proportion to the extent of cAMP production in the cell as a result of hormone receptor binding. The invention also provides melanocortin receptor agonists identified by the methods and using the screening panel of the invention. In preferred embodiments, the agonist is an agonist of the MC-3 mammalian melanocortin receptor. In other preferred embodiments, the agonist is an agonist of the MC-4 mammalian melanocortin receptor. The invention provides melanocortin receptor antagonists identified by the methods and using the screening panel of the invention. In preferred embodiments, the antagonist is an antagonist of the MC-3 mammalian melanocortin receptor. In other preferred embodiments, the antagonist is an antagonist of the MC-4 mammalian melanocortin receptor. The invention also provides methods for characterizing mammalian melanocortin receptor agonists for the capacity to modify or influence metabolism and feeding behavior in an animal. In a first aspect, the invention provides a method for characterizing melanocortin receptor MC-3 or MC-4 agonists as inhibitors of feeding behavior in an animal, the method comprising the steps of providing food to an animal that has been deprived of food for at least 12 hours, with or without administering to the animal an MC-3 or MC-4 receptor agonist of the invention, and comparing the amount of food eaten by the animal after administration of the MC-3 or MC-4 receptor agonist with the amount of food eaten by the animal without administration of the MC-3 or MC- 4 receptor agonist. In another aspect, the invention provides a method for characterizing a melanocortin MC-3 or MC-4 receptor antagonist as a stimulator of feeding behavior in an animal. In this embodiment, the method comprises the steps of providing food to an animal not deprived of food for at least 12 hours, with or without administering to the animal an MC-3 or MC-4 receptor antagonist, immediately prior to the onset of darkness or nighttime, and comparing the amount of food eaten by the animal after administration of the MC-3 or MC-4 receptor antagonist with the amount of food eaten by the animal without administration of the MC-3 or MC-4 receptor antagonist. Thus, the invention also provides methods for using certain of the melanocortin receptor agonists and antagonists for modifying feeding behavior in an animal. In a first aspect, the invention provides a method for stimulating feeding in an animal, the method comprising administering to the animal an MC-3 or MC-4 receptor antagonist. In a preferred embodiment, the antagonists are administered systemically. In additional embodiments, the antagonists are administered intracerebroventricularly. In another aspect, the invention provides a method for inhibiting feeding in an animal, the method comprising administering to the animal an MC-3 or MC-4 receptor agonist. In a preferred embodiment, the agonists are administered systemically. In additional embodiments, the agonists are administered intracerebroventricularly. In yet another aspect, the invention provides mammalian melanocortin receptor agonists having the general formula: A-B-C-D-E-F-G-amide wherein A is an aliphatic amino acid residue, including for example Leu, He, Nle and Met, as well as analogues and substituted derivatives thereof; B is an acidic amino acid residue, including for example Asp and Glu; C is a basic amino acid residue, such as His; D is an aromatic amino acid residue having a D- conformation, including D-Phe, D- Tyr and substituted derivatives thereof; E is a basic amino acid residue, for example Arg, Lys, homoArg, homoLys, and analogues or substituted derivatives thereof; F is Trp or substituted derivatives thereof; and G is Lys, homoLys or a substituted derivative thereof. In the peptide embodiments of the melanocortin receptor agonists of the invention, the peptide is cyclized by the formation of an amide bond between the side chain carboxyl group of the Asp or Glu residue at position B in the peptide, and the side chain amino group of the Lys or homoLys residue at position G. In preferred embodiments, the melanocortin receptor agonists of the invention are agonists of the MC-3 or MC-4 receptor. The invention also provides mammalian melanocortin receptor antagonists having the general formula: A-B-C-D-E-F-G-amide wherein A is an aliphatic amino acid residue, including for example Leu, He, Nle and Met, as well as analogues and substituted derivatives thereof; B is an acidic amino acid residue, including for example Asp and Glu; C is a basic amino acid residue, such as His; D is an aromatic amino acid residue having a D- conformation, including D-Nal and substituted derivatives thereof; E is a basic amino acid residue, for example Arg, Lys, homoArg, homoLys, and analogues or substituted derivatives thereof; F is Trp or substituted derivatives thereof; and G is Lys, homoLys or a substituted derivative thereof. In the peptide embodiments of the melanocortin receptor antagonists of the invention, the peptide is cyclized by the formation of an amide bond between the side chain carboxyl group of the Asp or Glu residue at position B in the peptide, and the side chain amino group of the Lys or homoLys residue at position G. In preferred embodiments, the melanocortin receptor antagonists of the invention are agonists of the MC-3 or MC-4 receptor. It is an advantage of the present invention that it provides an in vitro screening method for characterizing compounds having melanocortin receptor activities that relate to feeding behavior in animals. Specifically, the invention advantageously provides means and methods for identifying compounds having melanocortin receptor agonist and/or antagonist activity that have been associated with either stimulating or inhibiting feeding behavior when administered to an animal. The invention thus provides an economical first step in screening compounds for the capacity to affect feeding behavior, including synthetic, peptidomimetic or organomimetic derivatives of melanocortin receptor agonists or antagonists as disclosed herein or elsewhere. Specific preferred embodiments of the present invention will become evident from the following more detailed description of certain preferred embodiments and the claims. DESCRIPTION OF THE DRAWINGS Figures 1A and IB illustrate the nucleotide (SEQ ID No.: 3) and amino acid (SEQ ID No.: 4) sequence of the mouse melanocyte stimulating hormone receptor gene. Figures 2A and 2B illustrate the nucleotide (SEQ ID No.: 5) and amino acid (SEQ ID No.: 6) sequence of the human melanocyte stimulating hormone receptor gene. Figures 3 A and 3B illustrate the nucleotide (SEQ ID No.: 7) and amino acid (SEQ ID No.: 8) sequence of the human adrenocorticotropic stimulating hormone receptor gene. Figures 4A and 4B illustrate the nucleotide (SEQ ID No.: 9) and amino acid (SEQ ID No.: 10) sequence of the bovine adrenocorticotropic stimulating hormone receptor gene. Figures 5 A and 5B illustrate the nucleotide (SEQ ID No.: 11) and amino acid (SEQ ID No.: 12) sequence of the rat melanocortin-3 receptor gene. Figures 6A and 6B illustrate the nucleotide (SEQ ID No.: 15) and amino acid (SEQ ID No.: 16) sequence of the human melanocortin-4 receptor gene. Figures 7A and 7B illustrate the nucleotide (SEQ ID No.: 17) and amino acid (SEQ ID No.: 18) sequence of the mouse melanocortin-5 receptor gene. Figure 8 shows a graph of intracellular cAMP accumulation resulting from melanocyte stimulating hormone receptor agonist binding in human 293 cells transfected with a MSH receptor-encoding recombinant expression construct, wherein -□- represents binding of NDP-MSH, -o- represents binding of ACTH and -Δ- represents binding of αMSH. Figure 9 illustrates the cAMP response of mouse Yl cells to binding of melanocortin peptides to human melanocortin-2 (ACTH) receptor, as measured by the β-galactosidase assay described in Example 4, wherein -■- represents binding to wild- type ACTH-R and -A- represents binding to an ACTH-R variant. Figure 10 illustrates the results of competition binding experiments of melanocortin peptides to cells expressing a recombinant expression construct encoding the rat melanocortin-3 receptor, wherein -■- represents binding of NDP-MSH, -A- represents binding of γMSH, -•- represents binding of αMSH, -o- represents binding of ACTH 4.10 and -□- represents binding of ORG2766. Figures 1 1A through 11C illustrate the results of experiments showing intracellular cAMP accumulation caused by receptor-ligand binding in human 293 cells expressing the MC-3 receptor. In Figure 1 1A, -•- represents binding of αMSH, -■- represents binding of γ 2 -MSH, -A- represents binding of des-acetyl αMSH and -D- represents binding of ACTH,. 39 . In Figure 1 IB, -•- represents binding of γ, -MSH, -■- represents binding of γ 2 -MSH and -A- represents binding of des-acetyl γ -MSH. In Figure 11C, -•- represents binding of ACTH 4 . 10 , -■- represents binding of NDP-MSH and -A- represents binding of ORG2766. Figure 12 shows a graph of intracellular cAMP accumulation resulting from peptide binding to human melanocortin-4 receptor agonist in human 293 cells transfected with a MC-4 receptor-encoding recombinant expression construct, wherein -□- represents binding of ACTH^o, -•- represents binding of ACTH,. 39 , -■- represents binding of NDP-MSH, -o- represents binding of αMSH, -Δ- represents binding of γ 2 - MSH, and -A- represents binding of des-acetyl αMSH. Figure 13 illustrates the results of cAMP accumulation and cAMP-dependent β- galactosidase assays of melanocortin peptide binding to a rat melanocortin-5 receptor, wherein -□- represents binding of αMSH, -Δ- represents binding of β-MSH, and -o- represents binding of γ-MSH, each determined using the β-gal method, and wherein -■- represents binding of αMSH, -A- represents binding of β-MSH, and -•- represents binding of γ-MSH, each determined using the cAMP method. Figure 14 illustrates the structure of the pCRE/ β-gal plasmid. Figure 15 illustrates the results of the β-galactosidase-coupled, colorimetric melanocortin receptor binding assay using cells expressing each of the MC- 1, MC-3, MC4 or MC-5 receptors and contacted with αMSH or a variety of αMSH analogues, wherein -■- represents binding of αMSH, -A- represents binding of NDP-MSH, -•- represents binding of SHU9128 (para-¥\ substituted), -□- represents binding of SHU9203 (/--Cl substituted), -Δ- represents binding of SHU8914 (p-\ substituted), and -o- represents binding of SHU9119. Figures 16A through 16 D show the results of the β-galactosidase-coupled, colorimetric melanocortin receptor binding assay to determine antagonist activity of melanocortin analogues SHU9119 and SHU8914 in cells expressing each of the melanocortin receptors MC-3 and MC-4. In Figure 16A, -■- represents binding of αMSH, -□- represents binding of lOOnM SHU9119, -Δ- represents binding of lOnM SHU9119, and -o- represents binding of InM SHU91 19. In Figure 16B, -■- represents binding of αMSH, -□- represents binding of lOOnM SHU9119, -Δ- represents binding of 50nM SHU9119, and -o- represents binding of lOnM SHU9119. In Figure 16C, -■- represents binding of αMSH, -□- represents binding of lOOOnM SHU8914, -Δ- represents binding of lOOnM SHU8914, and -o- represents binding of lOnM SHU8614. In Figure 16D, -■- represents binding of αMSH, -□- represents binding of lOOnM SHU8914, -Δ- represents binding of 50nM SHU8914, and -o- represents binding of lOnM SHU8614. Figure 17 shows the results of classic competition binding assays using the melanocortin analogues SHU9119 and SHU8914 at the MC3-R and MC-4 R receptors, wherein -■- represents binding of NDP-MSH, -Δ- represents binding of SHU8914 (p-l substituted), and -o- represents binding of SHU91 19. Figures 18A and 18B shows the results of cAMP accumulation experiments (performed using the β-galactosidase assay of Example 4) for rat MC-3 receptor (Figure 18 A) and for mouse MC-4 receptor (Figure 18B). In Figure 18 A, -■- represents binding of NDP-MSH, -A- represents binding of MTII and -▼- represents binding of forskolin. In Figure 18B, -■- represents binding of MTII, -A- represents binding of NDP-MSH and -Y- represents binding of forskolin. Figures 19A through 19C show the effect on food intake of intracerebroventricular administration of melanocortin analogue SHU91 19 in mice. In Figure 19A, -■- represents administration of acsf (n=7) and -•- represents administration of 6nmol of SHU91 19 (n=6). In Figure 19B, -■- represents administration of acsf (n=6) and -□- represents administration of όnmol of SHU9119 (n=6). In Figure 19C, -o- represents administration of acsf (n=l 1) and -•- represents administration of όnmol of SHU9119 (n=12). Figures 20A through 20C show the effect on food intake of intracerebroventricular administration of melanocortin analogue MTII in mice. In Figure 20A, -•- represents administration of acsf (n=8), -T- represents administration of O.lnmol MTII (n=8), -■- represents administration of lnmol MTII (n ** =7) and -A- represents administration of 3nmol MTII (n=9). In Figure 20B, -•- represents administration of acsf (n= 12), -□- represents administration of 3nmol MTII and όnmol SHU9119 (n=9) and -A- represents administration of 3nmol MTII (n=9). Figure 20D shows the effect on locomotor activity of intracerebroventricular administration of melanocortin analogue MTII in mice, wherein -■- represents administration of vehicle alone (n=6) and -A- represents administration of 3nmol MTII (n=6). Figures 21 A through 2 ID show the effect on food intake of intracerebroventricular administration of melanocortin analogue MTII in mice. In Figure 21 A, -•- represents administration of acsf (n=6) and -A- represents administration of 3nmol MTII (n=7). In Figure 2 IB, open bars represent administration of acsf (n=6), solid bars represents administration of l.lδnmol neuropeptide Y (NPY; n=6) and stipled bars represents administration of 3nmol MTII and 1.18nmol NPY (n=6). In Figure 21C, -•- represents administration of acsf (n=7) and -A- represents administration of 3nmol MTII (n=7). In Figure 21 D, -■- represents administration of lOOnmol MTII (n=6) and -A- represents administration of vehicle alone (n=6). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The term "melanocortin receptor" as used herein reference to proteins having the biological activity of any of the disclosed melanocortin receptors, including the MC-1 (SEQ ID Nos.: 3, 4, 5 and 6), MC-2 (ACTH; SEQ ID Nos.: 7, 8, 9 and 10), MC-3 (SEQ ID Nos.: 1 1 and 12), MC-4 (SEQ ID Nos.: 15 and 16) or MC-5 (SEQ ID Nos.: 17 and 18) receptors, as well as naturally-occurring and genetically-engineered allelic variations in these sequences. Cloned nucleic acid provided by the present invention may encode MC receptor protein of any species of origin, including, for example, mouse, rat, rabbit, cat, and human, but preferably the nucleic acid provided by the invention encodes MC receptors of mammalian, most preferably rodent and human, origin. The production of proteins such as the MC receptors from cloned genes by genetic engineering means is well known in this art. The discussion which follows is accordingly intended as an overview of this field, and is not intended to reflect the full state of the art. DNA which encodes MC receptors may be obtained, in view of the instant disclosure, by chemical synthesis, by screening reverse transcripts of mRNA from appropriate cells or cell line cultures, by screening genomic libraries from appropriate cells, or by combinations of these procedures, as illustrated below. Screening of mRNA or genomic DNA may be carried out with oligonucleotide probes generated from the MC receptor gene sequence information provided herein. Probes may be labeled with a detectable group such as a fluorescent group, a radioactive atom or a chemiluminescent group in accordance with know procedures and used in conventional hybridization assays, as described in greater detail in the Examples below. In the alternative, MC receptor gene sequences may be obtained by use of the polymerase chain reaction (PCR) procedure, with the PCR oligonucleotide primers being produced from the MC receptor gene sequences provided herein. See U.S. Patent Nos. 4,683,195 to Mullis et al. and 4,683,202 to Mullis. MC receptor proteins may be synthesized in host cells transformed with a recombinant expression construct comprising a nucleic acid encoding each of the receptors disclosed herein. Such a recombinant expression construct can also be comprised of a vector that is a replicable DNA construct. Vectors are used herein either to amplify DNA encoding an MC receptor and/or to express DNA which encodes an MC receptor. For the purposes of this invention, a recombinant expression construct is a replicable DNA construct in which a DNA sequence encoding an MC receptor is operably linked to suitable control sequences capable of effecting the expression of the receptor in a suitable host cell. The need for such control sequences will vary depending upon the host selected and the transformation method chosen. Generally, control sequences include a transcriptional promoter, an optional operator sequence to control transcription, a sequence encoding suitable mRNA ribosomal binding sites, and sequences which control the termination of transcription and translation. Amplification vectors do not require expression control domains. All that is needed is the ability to replicate in a host, usually conferred by an origin of replication, and a selection gene to facilitate recognition of transformants. See, Sambrook et al, 1990, Molecular Cloning: A Laboratory Manual (Cold Spring Harbor Press: New York). Also specifically provided by the invention are reporter expression constructs comprising a nucleic acid encoding a protein capable of expressing a detectable phenotype, such as the production of a detectable reporter molecule, in a cell expressing the construct. Such constructs can be used for producing recombinant mammalian cell lines in which the reporter construct is stably expressed. Most preferably, however, the reporter construct is provided and used to induce transient expression over an experimental period of from about 18 to 96 h-rs in which detection of the reporter protein-produced detectable metabolite comprises an assay. Such reporter expression constructs are also provided wherein induction of expression of the reporter construct is controlled by a responsive element operatively linked to the coding sequence of the reporter protein, so that expression is induced only upon proper stimulation of the responsive element. Exemplary of such a responsive element is a cAMP responsive element (CRE), which induces expression of the reporter protein as a result of an increase in intracellular cAMP concentration. In the context of the present invention, such a stimulus is associated with melanocortin receptor binding, so that a reporter construct comprising one or more CREs is induced to express the reporter protein upon binding of a receptor agonist to a MC receptor in a recombinantly transformed mammalian cell. Production and use of such a reporter construct is illustrated below in Example 5. Vectors useful for practicing the present invention include plasmids, viruses (including phage), retroviruses, and integratable DNA fragments (i.e., fragments integratable into the host genome by homologous recombination). The vector replicates and functions independently of the host genome, or may, in some instances, integrate into the genome itself. Suitable vectors will contain replicon and control sequences which are derived from species compatible with the intended expression host. A preferred vector is the plasmid pcDNA/neo I. Transformed host cells are cells which have been transformed or transfected with recombinant expression constructs made using recombinant DNA techniques and comprising mammalian MC receptor-encoding sequences. Preferred host cells are human 293 cells. Preferred host cells for the MC-2 (ACTH) receptor are Yl cells (subclone OS3 or Y6). Transformed host cells are chosen that ordinarily express functional MC receptor protein introduced using the recombinant expression construct. When expressed, the mammalian MC receptor protein will typically be located in the host cell membrane. See, Sambrook et al, ibid. Cultures of cells derived from multicellular organisms are a desirable host for recombinant MC receptor protein synthesis. In principal, any higher eukaryotic cell culture is workable, whether from vertebrate or invertebrate culture. However, mammalian cells are preferred, as illustrated in the Examples. Propagation of such cells in cell culture has become a routine procedure. See Tissue Culture. Academic Press, Kruse & Patterson, editors (1973). Examples of useful host cell lines are human 293 cells, VERO and HeLa cells, Chinese hamster ovary (CHO) cell lines, mouse Yl (subclone OS3), and WI138, BHK, COS-7, CV, and MDCK cell lines. Human 293 cells are preferred. Cells expressing mammalian MC receptor proteins made from cloned genes in accordance with the present invention may be used for screening agonist and antagonist compounds for MC receptor activity. Competitive binding assays are well known in the art and are described in the Examples below. Such assays are useful for drug screening of MC receptor agonist and antagonist compounds, as detected in receptor binding assays as described below. One particular use of such screening assays are for developing drugs and other compounds useful in modifying or changing feeding behavior in mammals. The invention provides an assay system, comprising a panel of recombinant mammalian cells, heterologously expressing each of the MC receptors disclosed herein, wherein the panel is constructed of at least one cell line expressing an MC receptor, and most preferably comprising cells expressing each of the MC receptors. The invention provides such panels also comprising a detection means for detecting receptor agonist or antagonist binding, such as the reporter expression constructs described herein, using direct binding and competition binding assays as described in the Examples below. In the use of this panel, each MC receptor is assayed for agonist or antagonist patterns of binding a test compound, and a characteristic pattern of binding for all MC receptors is thereby determined for each test compound. This pattern is then compared with known MC receptor agonists and antagonists to identify new compounds having a pattem of receptor binding activity associated with a particular behavioral or physiological effect. For example, provided herein is experimental evidence that MC-3 or MC-4 receptor antagonists are capable of stimulating feeding in hungry animals, and that MC-3 or MC-4 agonists are capable of inhibiting feeding in animals otherwise stimulated to eat. The invention provides an in vitro assay to characterize MC-3 and MC-4 agonists/antagonists as a preliminary and economical step towards developing feeding behavior-modulating drugs for use in vivo. These results on feeding behavior in vivo have been obtained with certain MC receptor binding analogues, SHU9119 and MTII. These compounds have the following chemical structure: Ac-Nlβ' , ^βp s -Hi» β -βNa 2') 7 WfB«.T »- yβ ,0 -NH 2 SHU-9119 Ac.Nle .A β p 5 -His β -£2Phe 7 -A B».Tφ 9 -Ly5 ,0 ^H 2 MT-D Generally, those skilled in the art will recognize that peptides as described herein may be modified by a variety of chemical techniques to produce compounds having essentially the same activity as the unmodified peptide, and optionally having other desirable properties. For example, carboxylic acid groups of the peptide, whether carboxyl-terminal or sidechain, may be provided in the form of a salt of a pharmaceutically-acceptable cation or esterified to form a C,-C, 6 ester, or converted to an amide of formula NR,R 2 wherein R, and R 2 are each independently H or C,-C 16 alkyl, or combined to form a heterocyclic ring, such as 5- or 6-membered. Amino groups of the peptide, whether amino-terminal or sidechain, may be in the form of a pharmaceutically-acceptable acid addition salt, such as the HC1, HBr, acetic, benzoic, toluene sulfonic, maleic, tartaric and other organic salts, or may be modified to C,-C 16 alkyl or dialkyl amino or further converted to an amide. Hydroxyl groups of the peptide sidechain may be converted to C,-C 16 alkoxy or to a C,-C 16 ester using well- recognized techniques. Phenyl and phenolic rings of the peptide sidechain may be substituted with one or more halogen atoms, such as fluorine, chlorine, bromine or iodine, or with C→-C 16 alkyl, C, -C 16 alkoxy, carboxylic acids and esters thereof, or amides of such carboxylic acids. Methylene groups of the peptide sidechains can be extended to homologous C 2 -C 4 alkylenes. Thiols can be protected with any one of a number of well-recognized protecting groups, such as acetamide groups. Those skilled in the art will also recognize methods for introducing cyclic structures into the peptides of this invention to select and provide conformational constraints to the structure that result in enhanced binding and/or stability. For example, a carboxyl-terminal or amino-terminal cysteine residue can be added to the peptide, so that when oxidized the peptide will contain a disulfide bond, thereby generating a cyclic peptide. Other peptide cyclizing methods include the formation of thioethers and carboxyl- and amino-terminal amides and esters. Peptidomimetic and organomimetic embodiments are also hereby explicitly declared to be within the scope of the present invention, whereby the three- dimensional arrangement of the chemical constituents of such peptido- and organomimetics mimic the three-dimensional arrangement of the peptide backbone and component amino acid sidechains in the peptide, resulting in such peptido- and organomimetics of the peptides of this invention having substantial biological activity. It is implied that a pharmacophore exists for the receptor agonist and antagonist properties of these and related MC receptor binding analogues. A pharmacophore is an idealized, three-dimensional definition of the structural requirements for biological activity. Peptido- and organomimetics can be designed to fit each pharmacophore with current computer modeling software (computer aided drug design). MC receptor binding analogues derived using such software and comprising peptido- and organomimetics of SHU9119 and MTII and related analogues are within the scope of the claimed invention. The MC receptor binding analogues, in particular those analogues that are MC-3 or MC-4 receptor agonists or antagonists are provided to be used in methods of influencing, modifying or changing feeding behavior in mammals in vivo. Specific examples of uses for the MC receptor binding analogues of the invention include but are not limited to treatment of eating disorders such as anorexia and obesity, and other pathological weight and eating-related disorders. Other examples are failure to thrive disorders and disease-related cachexia, such as occurs in cancer patients. Also within the scope of the analogues of the invention is use for enhancing appearance, athletic ability, or adjuvant to other therapies to treat disorders such as high blood pressure, high serum cholesterol, vascular and heart disease, stroke, kidney disease, diabetes and other metabolic disorders. The Examples which follow are illustrative of specific embodiments of the invention, and various uses thereof. They set forth for explanatory purposes only, and are not to be taken as limiting the invention. EXAMPLE 1 Isolation of an αMSH Receptor Probe by Random PCR Amplification of Human Melanoma cDNA Using Degenerate Oligonucleotide Primers In order to clone novel G-protein coupled receptors, cDNA prepared from RNA from human melanoma cells was used as template for a polymerase chain reaction (PCR)-based random cloning experiment. PCR was performed using a pair of degenerate oligonucleotide primers corresponding to the putative third and sixth transmembrane regions of G-protein coupled receptors (Libert et al, 1989, Science 244: 569-72; Zhou et al, 1990, Nature 347: 76-80). The PCR products obtained in this experiment were characterized by nucleotide sequencing. Two novel sequences representing novel G-protein-coupled receptors were identified. PCR amplification was performed as follows. Total RNA was isolated from a human melanoma tumor sample by the guanidinium thiocyanate method (Chirgwin et al, 1979, Biochemistry Jj5: 5294-5299). Double-stranded cDNA was synthesized from total RNA with murine reverse transcriptase (BRL, Gaithersburg, MD) by oligo-dT priming (Sambrook et al, ibid.). The melanoma cDNA mixture was then subjected to 45 cycles of PCR amplification using 500 picomoles of degenerate oligonucleotide primers having the following sequence: Primer III (sense): GAGTCGACCTGTG(C^)G(C/T)(C/G)AT(C/T)(A/G)CIIT(G/T)GAC(C/A)G(C/G)TAC (SEQ ID NO: 1) and Primer VI (anti sense): CAGAATTCAG(T/A)AGGGCAICCAGCAGAI(G/C)(G/A)(T/C)GAA (SEQ ID NO:2) in 100 μl of a solution containing 50 mM Tris-HCl (pH 8.3), 2.5 mM MgCl 2 , 0.01% gelatin, 200 μM each dNTP, and 2.5 units of Tag polymerase (Saiki et al, 1988, Science 239: 487-491). These primers were commercially synthesized by Research Genetics Inc. (Huntsville, AL). Each PCR amplification cycle consisted of incubations at 94°C for 1 min (denaturation), 45 C for 2 min (annealing), and "72 C for 2 min (extension). Amplified products of the PCR reaction were extracted with phenol/chloroform and precipitated with ethanol. After digestion with EcoRI and Sail, the PCR products were separated on a 1.2% agarose gel. A slice of this gel, cooesponding to PCR products of 300 basepairs (bp) in size, was cut out and purified using glass beads and sodium iodide, and the insert was then cloned into a pBKS cloning vector (Stratagene, LaJolla, CA). A total of 172 of such pBKS clones containing inserts were sequenced using Sequenase (U.S. Biochemical Corp., Cleveland, OH) by the dideoxynucleotide chain termination method (Sanger et al, 1977, Proc. Natl. Acad. Sci. USA 2 : 5463-5467). Two types of sequences homologous to other G-protein coupled receptors were identified. EXAMPLE 2A Isolation of a Mouse αMSH fMC-li Receptor cDNA Probes isolated in Example 1 was used to screen a Cloudman melanoma cDNA library in order to isolate a full-length cDNA cooesponding to the cloned probe. One clone was isolated from a library of 5 x 10 6 clones screened as described below in Example 2B. This clone contained an insert of 2.6 kilobases (kb). The nucleotide sequence of the complete coding region was determined (see co-owned U.S. Patent No. 5,532,347, incorporated by reference); a portion of this cDNA comprising the coding region was sequenced and is shown in Figures 1A and IB (SEQ ID Nos: 3 & 4). EXAMPLE 2B Isolation of a Human αMSH (MC-1) Receptor cDNA In order to isolate a human counterpart of the murine melanocyte αMSH receptor gene disclosed in Example 2A and co-owned U.S. Patent No. 5,532,347, a human genomic library was screened at high stringency (50% formamide, 42 °C) using the human PCR fragments isolated as described in Example 1. A genomic clone was determined to encode an human MSH receptor (SEQ ID NO: 5). The human MSH receptor has a predicted amino acid sequence (SEQ ID NO: 6) that is 75% identical and colinear with the mouse αMSH receptor cDNA sequence (Figures 2A and 2B, represented as human MSH-R). The predicted molecular weight of the human MSH R is 34.7kD. EXAMPLE 2C Isolation of a Human ACTH (MC-2. Receptor cDNA For cloning the ACTH receptor (MC-2), a human genomic library was screened at high stringency (50% formamide, 1M NaCl, 50nM Tris-HCl, pH 7.5, 0.1 % sodium pyrophosphate, 0.2% sodium dodecyl sulfate, lOO g/ml salmon sperm DNA, 10X Denhardt's solution, 42°C), using the human PCR fragments isolated as described in Example 1 herein and U.S. Patent No. 5,280,112, incorporated by reference. A genomic clone was isolated that encodes a highly related G-coupled receptor protein (SEQ ID NO:7 and Figures 3 A and 3B). The predicted amino acid sequence (SEQ ID NO:8) of this clone is 39% identical and also colinear, excluding the third intracellular loop and carboxy-terminal tail, with the human MSH receptor gene product. The predicted molecular weight of this putative ACTH R is 33.9 kilodaltons (kD). This clone was identified as encoding an MC-2 receptor based on its high degree of homology to the murine and human MSH receptors, and the pattern of expression in different tissue types, as described in Example 3 in U.S. Patent 5,280, 112. EXAMPLE 2D Isolation of a Bovine ACTH fMC-2 Receptor cDNA A bovine genomic DNA clone encoding the bovine counterpart of the MC-2 (ACTH) receptor was isolated from a bovine genomic library, essentially as described in Example 2C above, and its nucleotide sequence determined (as shown in Figures 4A and 4B; SEQ ID Nos:9 & 10). EXAMPLE 2E Isolation of a Rat γ-MSH fMC-3) Receptor cDNA The mouse αMSH receptor cDNA isolated as described in Example 2 A and co- owned U.S. Patent No. 5,532,347 was used to screen a rat hypothalamus cDNA library at low stringency (30% formamide, 5X SSC, 0.1 % sodium pyrophosphate, 0.2% sodium dodecyl sulfate, lOOμg/ml salmon sperm DNA, and 10% Denhardt's solution) at 42°C for 18h. A 1 kb cDNA clone was isolated and sequenced as described in co-owned U.S. Patent No. 5,532,347, and this clone used to re-screen the rat hypothalamus cDNA library at high stringency (same conditions as above except that formamide was present at 45%). A cDNA clone approximately 2.0 kb in length was isolated and analyzed as described in co-pending U.S. Application Serial No. 08/044,812, incorporated by reference; a portion of this cDNA comprising the coding region was sequenced and is shown in Figures 5 A and 5B (SEQ ID Nos:l 1 & 12). EXAMPLE 2F Isolation of a Human MC-4 Receptor DNA For cloning the MC-4 receptor, a human genomic library was screened at moderate stringency (40% formamide, 1M NaCl, 50mM Tris-HCl, pH 7.5, 0.1 % sodium pyrophosphate, 0.2% sodium dodecyl sulfate, lOOμg/ml salmon sperm DNA, 10X Denhardt's solution, 42°C), using rat PCR fragments isolated as described in Example 1 herein, with the exception that the following primers were used for PCR: Primer II (sense): GAGTCGACC(A/G)CCCATGTA(C/T)T(AGT)(C/T)TTCATCTG (SEQ ID NO: 13) and Primer VII (antisense): CAGAATTCGGAA(A/G)GC(A/G)TA(G/T)ATGA(A/G)GGGGTC (SEQ ID NO: 14) A genomic clone was isolated that encodes a highly related G-coupled receptor protein (SEQ ID NO: 15 and Figures 6A and 6B) on a 1.9kb Hmdlll fragment. The predicted amino acid sequence (SEQ ID NO: 16) of this clone is 55-61 % sequence identity with human MC-3 and MC-5 receptors, and 46-47% sequence identity with the human MC-1 and MC-2 (ACTH) receptor. EXAMPLE 2G Isolation of a Mouse MC-5 Receptor DNA One million clones from a mouse 129SVJ genomic library comprising 5,000,000 clones in the λFixII vector (Stratagene) was screened at low stringency (hybridization in 40% formamide at 42 °C, washing performed in 0.5X SSC at 60°C, as described above in Example 2E) using radiolabeled probed from the rat MC-3 and MC-4 receptors (as described in Examples 2E and 2F). Positively-hybridizing clones were isolated and sequenced, and the sequences obtained were compared to previously-isolated melanocortin receptor clones. One clone, comprising a previously-unknown sequence, was determined to encode the MC-5 melanocortin receptor. The nucleotide and amino acid sequences of this receptor are shown in Figures 7A and 7B (SEQ ID No.: 17 & 18). EXAMPLE 3 Construction of a Recombinant Expression Construct, DNA Transfection and Functional Expression of the MCR Gene Products In order to produce recombinant mammalian cells expressing each of the melanocortin receptors of Example 2, cDNA from each receptor was cloned into a mammalian expression construct, the resulting recombinant expression construct transfected into human 293 cells, and cell lines generated that expressed the melanocortin receptor proteins in cellular membranes at the cell surface. The mouse αMSH receptor was cloned by excising the entire coding region of the αMSH R (MC-1) cDNA insert comprising a 2.1kb fragment and subcloning this fragment into the Bam l/Xhol sites of pcDNAI/neo expression vector (Invitrogen, San Diego, CA). The resulting plasmid was prepared in large-scale through one cycle of CsCl gradient ultracentrifugation, and 20 μg of the plasmid transfected into each 100mm dish of 293 cells using the calcium phosphate method (see Chen & Okayama, 1987, /. 7: 2745-2752). After transfection, cells were cultured in DMEM media supplemented with 10% calf serum in a 3% CO 2 atmosphere at 37°C. Selection was performed with neomycin (G418; GIBCO) at a concentration of 1000 μg/ml; selection was started 72 hr after transfection and continued for 3 weeks. The αMSH R is known to couple to G-proteins and thereby activate adenyl cyclase, increasing intracellular levels of cAMP (see Buckley & Ramachandran, 1981, Proc. Natl. Acad. Sci. USA 78: 7431-7435; Grahame-Smith et al , 1967, J. Biol. Chem. 242: 5535-5541; Mertz & Catt, 1991 , Proc. Natl. Acad. Sci. USA 8£: 8525- 8529; Pawalek et al, 1976, Invest. Dermatol. ___: 200-209). This property of cells expressing the αMSH receptor was used analyze expression of the αMSH receptor in cell colonies transfected with the expression vectors described herein as follows. Cells ( " lxlO 6 ) were plated in 6- ell dishes, washed once with DMEM containing 1 % bovine serum albumin (BSA) and 0.5mM IBMX (a phosphodiesterase inhibitor), then incubated for 45 minutes at 37 °C with varying concentrations of the melanotropic peptides αMSH, βMSH, γMSH, the MSH peptide analogues Nle 4 , D-Phe 7 -αMSH (NDP-MSH), and ACTH. Following hormone treatment, the cells were washed twice with phosphate buffered saline and intracellular cAMP extracted by lysing the cells with 1ml of 60% ethanol. Intracellular cAMP concentrations were determined using an assay (Amersham) which measures the ability of cAMP to displace [8- 3 H] cAMP from a high affinity cAMP binding protein (see Gilman, 1970, Proc. Natl. Acad. Sci. USA 67: 305-312). The results of these experiments are shown in Figure 8. The abscissa indicates the concentration of each hormone and the ordinate indicates the percentage of basal intracellular cAMP concentration achieved by each treatment. Points indicate the mean of duplicate incubations; the standard error did not exceed 15% for any data point. None of the peptides tested induced any change in intracellular cAMP in cells containing the vector alone. Cells expressing the murine αMSH receptor responded to melanotropic peptides with a 2-3 fold elevation of intracellular cAMP, similar to levels of cAMP induced by these peptides in the Cloudman cell line (see Pawalek, 1985, Yale J. Biol Med. 58: 571-578). The EC 50 values determined for αMSH (2.0xlO "9 M), ACTH (8.0xlCP M) and the superpotent MSH analogue NDP-MSH (2.8xlO "n M) correspond closely to reported values (see Tatro et al. , 1990, Cancer Res. _i__: 1237-1242). As expected, the βMSH peptide had an EC 50 value comparable to αMSH, while γMSH had little or no activity (see Slominski et al, 1992, Life Sci. 50: 1103-1108), confirming the identity of this receptor as a melanocyte αMSH receptor. A similar series of experiments were performed using mouse Yl cells (subclone OS3; Schimmer et al, 1995, J. Cell. Physiol 16J: 164-171) expressing the human and bovine MC-2 (ACTH) receptor clones of Examples 2C and 2D. These results are shown in Figure 9, where the extent of cAMP responsive element-linked β-galactosidase activity (see Example 4, below) is shown with increasing concentrations of ACTH . The entire coding region of the MC-3 receptor cDNA insert, obtained as described above in the co-pending U.S. Serial No. 08/044,812, was contained in a 2.0kb restriction enzyme digestion fragment and was cloned into the BamHl/Xhol sites of pcDNA/neo I expression vector (Invitrogen, San Diego, CA). The resulting plasmid was prepared in large-scale through one cycle of CsCl gradient ultracentrifugation and 20 μg pcDNA/MC-3 receptor DNA were transfected into each 100 mm dish of 293 cells using the calcium phosphate method (see Chen & Okayama, 1987, Mol. Cell. Biol. 2: 2745- 2752). After transfection, cells were cultured in DMEM media supplemented with 10% calf serum in a 3% CO 2 atmosphere at 37°C. Selection was performed with neomycin (G418; GIBCO) at a concentration of 1000 μg/ml; selection was started 72 h after transfection and continued for 3 weeks. Specific binding of melanocortin peptides to cells expressing the MC-3 receptor was demonstrated by competition experiments using 12* T-labeled Nle 4 -D-Phe 7 -α-MSH (NDP-MSH, as described in Tatro et al, 1990, Cancer Res. 5Q: 1237-1242). Suspended cells (2xl0 5 ) were incubated at 37°C with 500,000 cpm of labeled peptide for 10 min in binding buffer (Ham's F10 media plus lOmM HEPES, pH 7.2, 0.25% bovine serum albumin, 500K IU/ml aprotinin, 100 μg/ml bacitracin and lmM 1 ,10-phenanthroline) in the presence or absence of the indicated concentrations of peptides. Maximum labeling was achieved within 10 min. The results of these experiments are shown in Figure 10. Labeled NDP-MSH binding to cells expressing the MC-3 receptor, produced as described above, is inhibited by competition with unlabeled peptides known to be melanocortin receptor agonists, having a relative order of potency as follows: NDP-MSH > γ-MSH > α-MSH > ACTH 4 ., 0 >» ORG2766. Approximate Kj values derived from this experiment are as shown in Table I: TABLE I cAMP production assays as described above were also used to analyze expression of MC3-R in cells transfected with the expression vectors described herein as follows. Cells (~5xl0 6 ) were plated in 6-well dishes, washed once with DMEM containing 1% bovine serum albumin (BSA) and 0.5mM IBMX (a phosphodiesterase inhibitor), then incubated for lh at 37°C with varying concentrations of the melanotropic peptides αMSH, γ 3 MSH, γMSH, the MSH peptide analogues Nle"-D-Phe 7 -αMSH (NDP-MSH), ACTH 4.|0 and ACTH, .39 . Following hormone treatment, the cells were washed twice with phosphate buffered saline and intracellular cAMP extracted by lysing the cells with 1ml of 60% ethanol. Intracellular cAMP concentrations were determined using an assay which measures the ability of cAMP to displace [8- 3 H] cAMP from a high affinity cAMP binding protein (see Gilman, 1979, Proc. Natl. Acad. Sci. USA £7: 305-312). The results of these experiments are shown in Figures 11A through 1 lC. The abscissa indicates the concentration of each hormone and the ordinate indicates the percentage of basal intracellular cAMP concentration achieved by each treatment. Points indicate the mean of duplicate incubations; the standard error did not exceed 15% for any data point. Figure 11A depicts the results of experiments using peptides found in vivo; Figure 1 IB depicts results found with γ-MSH variants; and Figure 1 1C shows results of synthetic melanocortin analogues. None of the peptides tested induced any change in intracellular cAMP in cells containing the vector alone. Cells expressing rat MC3-R responded strongly to every melanotropic peptide containing the MSH sequence His-Phe-Arg-Trp, with up to a 60-fold elevation of intracellular cAMP levels. EC 50 values ranged from 1-50 nM. The most potent ligand and the one having the lowest EC 50 was found to be γMSH. The order of potency for the naturally occurring melanocortins was found to be: γ 2 -MSH = γMSH > αMSH = ACTH,, 39 > γ 3 -MSH > --/es-acetyl-αMSH > ACTH 4.10 . Ec 50 values for these compounds are shown in Table II: TABLE II Additionally, a synthetic melanocortin peptide (ORG2766), known to have the greatest activity in vivo in stimulation of retention of learned behavior and in stimulation of neural regeneration, was unable to stimulate MC3-R-mediated cAMP production, and was also inactive as an antagonist. The results strongly indicate that this peptide does not bind to MC3-R protein. The MC-4 receptor was cloned in a 1.9kb H dlϋ genomic DNA fragment after PCR amplification of a lambda phage clone into pcDNAI/Neo (Invitrogen). This plasmid was stably introduced into human 293 cells by calcium phosphate co- precipitation using standard techniques, and plasmid-containing cells selected in G418 containing media. Specificity of receptor-hormone binding was assayed using adenylate cylcase activity as described above. The MC-4 receptor was found to couple to adenylate cyclase activity having the following pattern of agonist affinity: NDP-MSΗ > des-acetyl-α-MSΗ >/= ACTΗ,. 39 >/= α-MSH > > γ 2 -MSH = ACTH. 4-10 whereas the synthetic ACTH 4 . 9 analogue ORG2766 showed no detectable binding to the MC-4 receptor. The results of adenylate cyclase activity assays are shown in Figure 12. EC 50 values for each of the tested MC-4 receptor agonists are as shown in Table III: TABLE III A l .όkb Apal-Hindlϊϊ fragment comprising the entire coding sequence of the mouse MC-5 melanocortin receptor disclosed in Example 2G above was cloned into the pcDNA/neo expression vector (Invitrogen) after PCR amplification of the lambda phage clone. This plasmid was stably introduced into human 293 cells by calcium phosphate co-precipitation using standard techniques, and plasmid-containing cells selected in G418 containing media. Specificity of receptor-hormone binding was assayed using adenylate cylcase activity as described above. The MC-5 receptor was found to couple to adenylate cyclase activity having the following pattern of agonist affinity: α-MSH > βMSH > > γ-MSH The results of adenylate cyclase activity assays are shown in Figure 1 . EC 50 values for each of the tested MC-5 receptor agonists are: α-MSH * -=l .7 x 10 "9 M; and βMSH = 5 x 10 "9 M. EXAMPLE 4 Melanocortin Analogue Binding to Mammalian Melanocortin Receptors Recombinant cells prepared as described above in Example 3 were used to characterize receptor binding of two melanocortin analogues comprising cyclic lactam heptapeptides. The melanocortin receptor analogue SHU9119 has the following chemical structure: Ac-Nle 4 -cyclo(Asp 5 , D-Nal(2) 7 , Lys 10 ) αMSH-(4- 10)-amide The melanocortin receptor analogue MTII has the following chemical structure: Ac-Nle -cyclo(Asp 5 , His 6 , D-Phe 7 , Arg 8 , Tφ 9 , Lys 10 ) αMSH-(4-10)-amide These analogues were prepared as described in Hruby et al. (1995, J Med. Chem. 38: 3454-3461). These analogues were tested for melanocortin receptor binding using a colorimetric assay system developed by some of the instant inventors (Chen et al, 1995, Analyt. Biochem. 226: 349-354) as follows. A series of concatamers of the synthetic oligonucleotide: 5 '-GAATTCGACGTCACAGTATGACGGCCATGG-3 ' (SEQ ID No: 19) was produced by self-annealing and ligation and a tandem tetramer obtained. This fragment was cloned upstream of a fragment of the human vasoactive intestinal peptide (-93-+152; SEQ ID No.: 13; see Fink et al, 1988, Proc. Natl Acad. Sci. USA 85: 6662- 6666). This promoter was then cloned upstream of the β-galactosidase gene from E. coli. The resulting plasmid construct is shown in Figure 14. Transient transfection of the pCRE/β-gal plasmid described above was performed as follows. Cells grown to between 40-60% confluency (corresponding to about 1.5 million cells/6cm tissue culture plate) were incubated with Opti-MEM (GIBCO-BRL, Long Island, NY) and then contacted with a pCRE/β-gal-lipofectin complex which was prepared as follows. 3μg plasmid DNA and 20μL lipofectin reagent (GIBCO) were each diluted into 0.5mL Opti-MEM media and then mixed together. This mixture was incubated at room temperature for 15-20 min., and then the mixture (lmL) added to each 6cm plate. Transfected plates were incubated at 37 °C for 5-24h, after which the plates were washed and incubated with DMEM media (GIBCO) and the cells split equally into a 96-well culture plate. To assay melanocortin receptor analogue binding, human 293 cells expressing each of the melanocortin receptors MC-1, MC-3, MC-4 and MC-5, and mouse Yl cells expressing the MC-2 receptor, were transiently transfected with pCRE/β-gal as described above and assayed as follows. Two days after transfection, cells were stimulated with hormones specific for each receptor or hormone analogue by incubation for 6h at 37 °C with a mixture comprising 10 12 - 10 "6 M) hormone or analogue, 0.1 mg/mL bovine serum albumin and O.lmM isobutylmethylxanthine in DMEM. The effect of hormone or analogue binding was determined by β-galactosidase assay according to the method of Feigner et al. (1994, J. Biol. Chem. 269: 2550-2561). Briefly, media was aspirated from culture wells and 50μL lysis buffer (0.25M Tris-HCl, pH 8/0.1% Triton-XlOO) added to each well. Cell lysis was enhanced by one round of freezing and thawing the cell/lysis buffer mixture. lOμL aliquots were sampled from each well for protein determination using a commercially-available assay (BioRad, Hercules, CA). The remaining 40μL from each well was diluted with 40μL phosphate buffered saline/0.5% BSA and 150μL substrate buffer (60mM sodium phosphate/ ImM MgCl 2 / lOrnM KG/ 5mM β- mercaptoethanol/ 2mg/mL o-nitrophenyl-β-D-galactopyranoside) added. Plates were incubated at 37°C for lh and then absorbance at 405nm determined using a 96- well plate reader (Molecular Devices, Sunnyvale, CA). A series of two-fold dilutions from 20ng of purified β-galactosidase protein (Sigma Chemical Co, St. Louis, MO) were assayed in parallel in each experiment to enable conversion of OD 405 to known quantity of β- galactosidase protein. The results of these experiments are shown in Figure 15. This Figure shows the results of the β-galactosidase assay described above using cells expressing each of the MC-1 , MC-3, MC-4 or MC-5 receptors and contacted with αMSH or a variety of αMSH analogues, including SHU9119. These results showed that SHU91 19 had relatively weak agonist activity for both the human MC-3 and MC-4 receptors. These results demonstrated the development of a colorimetric assay for cAMP accumulation as the result of melanocortin receptor binding to agonists and antagonists. The action of MTII, SHU9119, and the endogenous mouse agouti peptide as agonists or antagonists of rodent MC receptors was first determined by examining their ability to elevate intracellular cAMP in 293 cell lines expressing the rat MC3-R or mouse MC4-R (expressed as IC 50 values representing ligand concentration required for half-maximal inhibition of binding of (I-125)-(Nle 4 , D-Ph 7 e )α-MSH tracer). Agonist/antagonist activity was also shown by demonstrating inhibition of cAMP elevation by the potent α-MSH analogue [Nle 4 , D-Phe 7 ]α-MSH, using either a cAMP- responsive β-galactosidase reporter construct as described above, or by direct adenyl cyclase assay as described in Example 3 (wherein EC 50 values represent ligand concentration required for half-maximal activation of a cAMP-responsive β- galactosidase reporter). Competition binding experiments were determined as the amount of radioactivity bound in the presence of 5xlO *6 M unlabeled [Nle 4 , D-Phe 7 ]α- MSH, and was typically 3-5% of total counts bound. In these experiments, murine agouti peptide was produced using a baculovirus system as described by Lu et al. (1994, Nature 37_1 : 799-802), with the modification that the agouti peptide was purified from baculovirus supernatants by 0.6M NaCl step elution from an EconoS cation exchange column (BioRad). Agouti peptide used in these assays was approximately 60% pure. Competition binding assays were performed to determine whether SHU9119 had antagonist activity towards αMSH binding to either the MC-3 or MC-4 receptors. These assays were performed as follows. Human 293 cells (100,000 cells/well in 24-well plates) expressing either the MC-3 or MC-4 receptors prepared as described above were incubated with a solution of lmg/mL BSA in PBS containing 100,000cpm (3.1 x 10 l0 M [ 125 I](Nle 4 , D-Phe 7 )αMSH and varying concentrations of αMSH, (Nle 4 , D-Phe 7 )αMSH or SHU91 19. Cells were incubated for 30min at 37 °C, washed twice with PBS-BSA, lysed with 0.5mL 0.5N NaOH, and counted using a γ-counter to quantitate the amount of bound [ 125 I](Nle 4 , D-Phe 7 )αMSH. Control experiments showed non-specific binding to occur at about 3-5% levels, and this was taken into account when analyzing the experimental results. The SHU9119 analogue was found to be a potent antagonist of both the human MC-3 and MC-4 receptors, as shown in Figure 16. These assays showed pA 2 values of 8.3 and 9.3 for the human MC-3 and MC-4 receptors, respectively, as determined using the method of Schild (1947, Brit. J. Pharmacol. 2: 189-206). In contrast, no significant alteration in IC 50 values was detected in binding experiments using this analogue with either the MC-3 or MC-4 receptors (Figure 17). The activity of the MTII analogue was also assayed for melanocortin receptor agonist activity. These results are shown in Figures 18A and 18B, and confirmed that the MTII analogue is a specific agonist of the MC-3 and MC-4 receptors. Specific competition of [Nle 4 ,D-Phe 7 ]α-MSH binding to rat MC-3 receptor by agouti peptide was observed, although accurate IC 50 values could not be determined because the peptide preparation was not homogenous (results not shown). Specific competition of α-MSH activation of human MC4-R by agouή was previously disclosed (Lu et al, 1994, Natur 371: 799-802). EXAMPLE 5 Feeding Behavior Effect of Melanocortin Analogue Binding in Brain The results shown in Example 4 above suggested a role in the regulation of feeding behavior in mammalian brain for MC receptor agonists and antagonists, in view of the antagonist properties of the agouti peptide at the MC-3 and MC-4 receptors. The agouti peptide was known to cause obesity when expressed ectopically in the mouse, and has been found to be a high affinity antagonist of the melanocyte stimulating hormone receptor (MC1-R) and of the hypothalamic MC-4 receptor (.see Lu et al, ibid.). The former activity explained the inhibitory effect of the agouti peptide on eumelanin pigment synthesis. Similarly, it was hypothesized by the inventors that agouti causes obesity in mice by antagonizing hypothalamic MC-4 receptors. The cyclic melanocortin analogue, SHU9119, having been shown herein and elsewhere (Hruby et al.) to be a specific, high affinity antagonist of the central MC-3 and MC-4 receptors, was tested for the effect of direct administration to mouse brain on feeding behavior in the animals. Intracerebroventricular (ICV) administration of SHU91 19 was performed to avoid any complications caused by inhibition of peptide traverse of the blood-brain barrier. Briefly, male C57B1/6J mice (18-29g) were maintained on a normal 12hr/12hr light dark cycle with food (Purina mouse chow) and water ad libitum. Animals were housed individually for 24 hrs, distributed into experimental and control groups, avoiding any bias as a function of prior weight, then injected with vehicle or vehicle plus drug just prior to the onset of a 12hr light or dark cycle. Fasted animals were deprived of food from 18:00 to 10:30 hrs to stimulate feeding during the daytime experimental period. Animals were lightly anesthetized with halothane, and administered into one lateral ventricle 2 μL of a solution of artificial cerebrospinal fluid alone (acsf, comprising 130mM NaCl, 27mM NaHCO 3 , 1.2mM Na HPQ , 0.3mM NaH P , 0.5mM Na^O,, l.OmM CaCl 2 , l.OmM MgCl 2 , and 2.5mM KC1), or όnmol SHU9119 in acsf. Freehand injections were performed as described by Laursen and Belknap (1986, J Pharmacol. Methods __: 355-357) with some modifications. A lOμl luertip syringe (Hamilton 701LT) was fitted with a 0.5 inch 27 gauge needle. Stiff tygon tubing was slipped over the needle to expose 3mM of the needle tip. The syringe was held at a 45 ° angle from the front of the skull with the bevel facing up. The coronal suture was found by lightly rubbing the needle over the skull. Maintaining the 45 ° angle, the needle was then inserted l-2mm lateral to the midline, using only mild pressure to insert and remove the needle. The compounds indicated in a 2μl volume of acsf were administered slowly over approximately 15 seconds, and the needle removed after 35 seconds. Animals were allowed to recover from anesthesia and placed into a cage containing a premeasured quantity of food pellets in a spill-free cup. Moribund animals were not included in the study. Stimulation of feeding by intracerebroventricular administration of the melanocortin antagonist SHU9119 is shown in Figures 19A through 19C. Curves show cumulative food intake as a function of time following administration of the substances shown. Figure 19A shows stimulation of feeding by administration of SHU9119 just prior to lights off (19:00 hrs) to C57B1/6J mice fed ad libitum. Figure 19B, in contrast, shows no effect of morning (10:00 hrs) SHU91 19 administration in C57B1/6J mice fed ad libitum. Figure 19C illustrates stimulation of daytime feeding by SHU9119 administration in fasted C57B1/6J mice. In deriving the data points comprising these Figures, food remaining was briefly removed and weighted at the time intervals indicated. Data points indicate the mean and bars indicate standard error. Significance of the effect over time was determined by ANOVA with repeated measures. Significance of drug effects at individual time points was determined by two-way ANOVA, and is indicated in each Figure (***=P<0.001, **=P<0.01, * * =P<0.05). These results demonstrated that ICV administration of SHU9119 into one lateral ventricle of the C57B1/6J mouse just prior to lights out led to a mean 60% increase in food intake over 12 hrs (Figure 19A; PO.005). In contrast, daytime food intake in animals fed ad libitum was not stimulated by administration of SHU9119 (Figure 19B). SHU9119-treatment did, however, significantly stimulate daytime food intake in animals fasted for 16 hrs prior to the experiment (Figure 19C; PO.001 ). Stimulation of feeding was evident at approximately two hrs post-treatment, and continued for 12 hrs, to produce a mean 34% in food intake relative to vehicle-injected controls. These results supported the hypothesis that agouti and or SHU9119 stimulate feeding by antagonizing MC receptors in the central nervous system. To further test this hypothesis, a series of experiments were performed wherein MC receptor agonists were administered to animals primed by fasting to eat, to determine whether feeding in such animals could be inhibited by the MC receptor agonists. Animals were induced to feed by food deprivation for 16h prior to ICV administration of the non-specific melanocortin agonist MTII. In these experiments, ICV injections in male C57B1/6J mice (20-30g) and the measurement of food intake were performed as described above. Results of these experiments are shown in Figures 20A through 20C. In comparison to vehicle-injected animals, MTII was found to produce a potent inhibition of feeding within one hour after administration (Figure 20A) in a dose-responsive manner. Food intake was significantly inhibited for up to four hours following administration (P<0.001) at the highest dose administered (3nmol), and decreased food intake continued for the next four hours with normal rates of food intake resuming at about 8 hours after treatment. This dose-responsive inhibition of feeding had an IC 50 at the two hour time point of approximately 0.5nmol (Figure 20B). However, inhibition of feeding with 3nmol MTII was completely blocked by co-administration of όnmol SHU9119 (Figure 20C; PO.001), demonstrating that the effect results specifically from agonist binding to the MC-4 and/or MC-3 receptor. Locomotor assays were performed to determine whether the effects on feeding behavior observed in these mice were secondary to generalized behavioral effects caused by administration of these melanocortin analogues. The effects of MTII on locomotor activity were tested by placing vehicle or MTII-treated mice in sound and light-proof cages containing multiple light beam detectors. These assays were performed by first injecting 3nmol MTII or acsf as described above. At three hours (2:45-3:25) post- injection, 12 mice were placed into 12 separate boxes containing multiple infrared light sources and photodetectors. The boxes were contained within separate ventilated light and sound attenuating chambers (Coulbourn model El 0-20). Disruption of the infrared beams, with a 10msec resolution, was tallied independently for each one minute time period in each cage. The results of these assays are shown in Figure 20D. Data points indicate the mean total activity (# of light breaks) for 6 animals in each experimental group. Four way ANOVA statistical analysis was used to analyze the data, and indicated an absence of a significant difference among the two groups. Inhibition of feeding by MTII could not be explained by any apparent behavioral abnormalities, or any effect on arousal or locomotor activity. MTII-treated animals appeared alert and exhibited no unusual behavior relative to controls. At approximately three hours after ICV administration, MTII-treated animals exhibited locomotor activity that was indistinguishable from vehicle-treated animals (Figure 20D). The higher initial activity, indicative of exploratory behavior, and continued locomotion over a 15 min period was indistinguishable between the two groups, indicating that the inhibition of feeding was not due to decreased locomotion or decreased arousal. The administration of MTII also inhibited food intake in three other models of hypeφhagia: the C57B\/6J-Lep ob mouse, a neuropeptide Y (NPY)-injected C57B1/6J mouse and a C57B1/6J-Λ V mouse. Figure 21 A shows inhibition of feeding by intracerebroventricular administration of MTII in A y mice (females, 19-28gms). Figure 2 IB shows inhibition of feeding by intracerebroventricular administration of MTII in C57B1/6J mice (females, 21-25gm) stimulated to feed by co-administration of NPY. Figure 21 C shows inhibition of feeding by intracerebroventricular administration of the MTII in ob/ob mice (females, 48-69 gms). Figure 21 D shows inhibition of feeding in ob/ob mice by intraperitoneal administration of MTII (females, 40-45 gms). ICV injections and measurement of food intake were performed as described above, with the exception of NPY treated animals, which were not fasted prior to experimentation. Animals treated intraperitoneally received lOOμl of a ImM solution of MTII in saline, and vehicle injections consisted of the same amount of saline alone. Significance indicated for individual time points, determined as described above, was for 3nmol MTII vs. acsf (Figure 21 A), 1.18 nmol NPY vs. 1.18 nmol NPY + 3 nmol MTII (Figure 2 IB), 3nmol MTII vs. acsf (Figure 21C), and 100 nmol MTII vs. saline (Figure 2 ID). The hypeφhagia in these models can be clearly seen by comparing the 12 hr food intake following a fast in vehicle-injected C57B1/6J (2.4g, Figure 19A), C57B1/6J-Λ *" (3.7g, Figure 21 A) and C57Bl/6J-Z,e/? ofc (3.7g. Figure 21C) animals. As expected, MTII treatment inhibited food intake following a 16 hr fast in the C57B1/6J- K mouse (Figure 21 A; PO.05). Interestingly, while food intake for the first four hours is significantly inhibited relative to vehicle-injected animals, it is also significantly less inhibited in the C57B l/6]-A r animal than in the C57B1/6J animal given the same 3nmol dose (compare, Figure 20A versus Figure 21 A, 1-4 hrs; P<0.001). The decreased effectiveness of the agonist in the presence of the A γ allele is consistent with the proposal that this allele results in chronic expression of agouti peptide melanocortin antagonist in the brain. MTII, upon co-administration, also significantly inhibited the profound stimulation of feeding induced by NPY, measured over a three hr period (Figure 21C; P<0.005). Co-administration of an approximately two-fold molar excess of MTII produced a 74% inhibition of NPY- stimulated food intake at the three hour time point. Finally, MTII also inhibited hypeφhagia due to absence of leptin in the C57Bl/6J-i.e/7 o6 mouse (Figure 21C; PO.001). MTII potently blocked feeding (Figure 20A) in these animals, in contrast to the less potent inhibition described above for the C57Bl/6J-^ >' mouse. The C57Bl/6J-Z,e/? ofc animal was also used to test the ability of MTII to regulate feeding when administered peripherally. Moderate doses (lOOnmol) of MTII inhibited feeding in the C57Bl/6J-Z,e/?° 6 mouse (P<0.001) while low doses (lOnmol) did not (date not shown). The kinetics were similar to those seen with ICV administration, with a potent inhibition of feeding for the first four hours. The 100-fold higher dose required peripherally, as well as the similar kinetics, suggest a primarily central nervous system -based mechanism of action of MTII. These data show that melanocortinergic neurons exert a tonic inhibition of feeding behavior, and that disruption of this signal leads to hypeφhagia. With regard to the recently-discovered leptin hormone made by adipocytes, which is generally expressed at elevated levels in obese humans and rodents (such as the C57Bl/6J-Ee 7 0i animal), the regulatory defect is understood to be an incapacity to respond properly to the leptin hormone signal. The instant results indicate that the melanocortins act independently, and physiologically "downstream," from the leptin hormone/receptor interaction, because it has been shown herein that melanocortin receptor agonists can potently inhibit feeding in the C57Bl/6J-Lep ob animal. These results suggest that MC receptor agonists and antagonists can affect mammalian feeding behavior, and provide a means for determining candidate compounds for the development of effective pharmacological products directed towards alleviating such human ailments as obesity, anorexia and cachexia. EXAMPLE 6 Use of MC Receptor-Expressing Recombinant Cells for Screening Compounds that Affect Feeding Behavior in Mammals The results obtained in Example 5 indicated that cells expressing a variety of mammalian melanocortin receptors are useful for characterizing compounds as a first step towards developing MC receptor agonists and antagonists for controlling feeding behavior in mammals, particularly obesity and overweight disorders in general, as well as anorexia, cachexia and other failure-to-thrive disorders. A panel of mammalian melanocortin receptor-expressing recombinant cells are provided as described above in Example 3, wherein each member of the panel comprises appropriate mammalian cells, such as human 293 cells, comprising a recombinant expression construct encoding the MC-1, MC-2 (ACTH), MC-3, MC-4 or MC-5 receptor, the panel constructed to comprise cells functionally expressing each of these MC receptor proteins. The panel is used as follows. Receptor agonist activity is assayed by transient or stable expression of a protein which produces a metabolite reporter molecule in response to receptor binding by any of the MC receptor proteins. An example of such a reporter system is the recombinant expression construct described in Example 4, wherein cAMP responsive elements (CREs) are operatively linked to a bacterially- derived β-galactosidase (β-gal) gene. In the event of receptor binding, cAMP is produced in the mammalian cell, and the CRE induces β-gal expression. When co- incubated with a colorless substrate for β-gal, receptor binding results in conversion of the colorless substrate to a blue-colored product, which can be easily scored visually or spectrophotometrically. Alternative reporter genes, such a luciferase, can also be used as reporter systems, provided that expression of the reporter molecule-producing protein is functionally linked to receptor binding of a test compound. Alternatively, cAMP production resulting from MC receptor binding can also be measured directly. Assay panels are arranged so that agonist activity can be identified, quantitated and correlated with expression of each MC receptor. Automated assays using such panels are also envisioned, whereby the qualitative and quantitative detection of a reporter metabolite is detected in an array (such as a 96-well tissue culture plate) and the data collected and assembled into a computer data-base or other analytical program. Antagonist activity is detected by a modification of the above assay. In this assay, the inhibition of cAMP production by a standardized amount of a known receptor agonist, specific for each receptor, is assayed in the presence of a putative antagonist compound. Production of metabolite reporter molecules and their qualitative and quantitative detection is achieved as described above, and the specificity and potency of each antagonist compound characterized with regard to the degree of inhibition achieved for each receptor. In view of the instant disclosure, MC-3/MC-4 receptor antagonists are expected to be useful to inhibit food intake in a hungry animal, and MC-3/MC-4 receptor agonists are expected to be useful to increase food intake in an animal. Alternative patterns of feeding behavior associated with different patterns of MC receptor agonist/antagonist activity can be determined using this assay. Compounds having agonist or antagonist activity with the MC-3 or MC-4 receptors detected using this assay are further screened in vivo to determine whether the observed receptor binding activity results in modification of feeding behavior when administered to an animal. In these assays, the MC receptor binding compounds detected using the assay are administered intracranioventricularly as described above in Example 5 to animals after an overnight fast, to waking animals, or to animals that are not otherwise primed to be hungry. Feeding and locomotor activity is monitored in these animals, and compounds affecting eating behavior (either by inhibiting feeding in otherwise hungry animals or stimulating feeding in otherwise sated animals) are selected for further development. In addition, systemic administration of compounds found to be active by ICV administration assays is used to screen such compounds for the ability to cross the blood- brain barrier. Such compounds are also useful as templates for modifications aimed at increasing the availability of these compounds in the brain after systemic administration, for increasing bioactivity, or both. It should be understood that the foregoing disclosure emphasizes certain specific embodiments of the invention and that all modifications or alternatives equivalent thereto are within the spirit and scope of the invention as set forth in the appended claims. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: (A) NAME: Oregon Health Sciences University (B) STREET: 3181 S.W. Sam Jackson Park Road (C) CITY: Portland (D) STATE: Oregon (E) COUNTRY: USA (F) POSTAL CODE (ZIP) : 97201 (G) TELEPHONE: 503-494-6200 (H) TELEFAX: 503-494-4729 (ii) TITLE OF INVENTION: Methods and Reagents for Discovering and Using Mammalian Melanocortin Receptor Agonists and Antagonists To Modulate Feeding Behavior in Animals (iii) NUMBER OF SEQUENCES: 19 (iv) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS -DOS (D) SOFTWARE: Patentin Release #1.0, Version #1.25 (v) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: (2) INFORMATION FOR SEQ ID NO : 1 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 35 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS : single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (ix) FEATURE: (A) NAME/KEY: mics_feature (B) LOCATION: 1..35 (D) OTHER INFORMATION: /function = "Degenerate oligonucleotide primer (sense)" /note= "The residue at positions 24 and 24 are inosme" (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 1 : GAGTCGACCT GTGYGYSATY RCNNTKGACM GSTAC 35 (2) INFORMATION FOR SEQ ID NO : 2 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) ( ix) FEATURE : (A) NAME/KEY: mics_feature (B) LOCATION: 1..32 (D) OTHER INFORMATION: /function = "Degenerate oligonucleotide primer (antisense)" /note= "The residue at position 18 is inosine" (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 2 : CAGAATTCAG WAGGGCANCC AGCAGASRYG AA 32 (2) INFORMATION FOR SEQ ID NO: 3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1260 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA to mRNA (ix) FEATURE: (A) NAME/KEY: 5'UTR (B) LOCATION: 1..14 ( ix) FEATURE : (A) NAME/KEY: CDS (B) LOCATION: 15..959 (ix) FEATURE: (A) NAME/KEY: 3'UTR (B) LOCATION: 960..1260 (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 3 : TTCCTGACAA GACT ATG TCC ACT CAG GAG CCC CAG AAG AGT CTT CTG GGT 50 Met Ser Thr Gin Glu Pro Gin Lys Ser Leu Leu Gly 1 5 10 TCT CTC AAC TCC AAT GCC ACC TCT CAC CTT GGA CTG GCC ACC AAC CAG 98 Ser Leu Asn Ser Asn Ala Thr Ser His Leu Gly Leu Ala Thr Asn Gin 15 20 25 TCA GAG CCT TGG TGC CTG TAT GTG TCC ATC CCA GAT GGC CTC TTC CTC 146 Ser Glu Pro Trp Cys Leu Tyr Val Ser He Pro Asp Gly Leu Phe Leu 30 35 40 AGC CTA GGG CTG GTG AGT CTG GTG GAG AAT GTG CTG GTT GTG ATA GCC 194 Ser Leu Gly Leu Val Ser Leu Val Glu Asn Val Leu Val Val He Ala 45 50 55 60 ATC ACC AAA AAC CGC AAC CTG CAC TCG CCC ATG TAT TAC TTC ATC TGC 242 He Thr Lys Asn Arg Asn Leu His Ser Pro Met Tyr Tyr Phe He Cys 65 70 75 TGC CTG GCC CTG TCT GAC CTG ATG GTA AGT GTC AGC ATC GTG CTG GAG 290 Cys Leu Ala Leu Ser Asp Leu Met Val Ser Val Ser He Val Leu Glu 80 85 90 ACT ACT ATC ATC CTG CTG CTG GAG GTG GGC ATC CTG GTG GCC AGA GTG 338 Thr Thr He He Leu Leu Leu Glu Val Gly He Leu Val Ala Arg Val 95 100 105 GCT TTG GTG CAG CAG CTG GAC AAC CTC ATT GAC GTG CTC ATC TGT GGC 386 Ala Leu Val Gin Gin Leu Asp Asn Leu He Asp Val Leu He Cys Gly 110 115 120 TCC ATG GTG TCC AGT CTC TGC TTC CTG GGC ATC ATT GCT ATA GAC CGC 434 Ser Met Val Ser Ser Leu Cys Phe Leu Gly He He Ala He Asp Arg 125 130 135 140 TAC ATC TCC ATC TTC TAT GCG CTG CGT TAT CAC AGC ATC GTG ACG CTG 482 Tyr He Ser He Phe Tyr Ala Leu Arg Tyr His Ser He Val Thr Leu 145 150 155 CCC AGA GCA CGA CGG GCT GTC GTG GGC ATC TGG ATG GTC AGC ATC GTC 530 Pro Arg Ala Arg Arg Ala Val Val Gly He Trp Met Val Ser He Val 160 165 170 TCC AGC ACC CTC TTT ATC ACC TAC TAC AAG CAC ACA GCC GTT CTG CTC 578 Ser Ser Thr Leu Phe He Thr Tyr Tyr Lys His Thr Ala Val Leu Leu 175 180 185 TGC CTC GTC ACT TTC TTT CTA GCC ATG CTG GCA CTC ATG GCG ATT CTG 626 Cys Leu Val Thr Phe Phe Leu Ala Met Leu Ala Leu Met Ala He Leu 190 195 200 TAT GCC CAC ATG TTC ACG AGA GCG TGC CAG CAC GTC CAG GGC ATT GCC 674 Tyr Ala His Met Phe Thr Arg Ala Cys Gin His Val Gin Gly He Ala 205 210 215 220 CAG CTC CAC AAA AGG CGG CGG TCC ATC CGC CAA GGC TTC TGC CTC AAG 722 Gin Leu His Lys Arg Arg Arg Ser He Arg Gin Gly Phe Cys Leu Lys 225 230 235 GGT GCT GCC ACC CTT ACT ATC CTT CTG GGG ATT TTC TTC CTG TGC TGG 770 Gly Ala Ala Thr Leu Thr He Leu Leu Gly He Phe Phe Leu Cys Trp 240 245 250 GGC CCC TTC TTC CTG CAT CTC TTG CTC ATC GTC CTC TGC CCT CAG CAC 818 Gly Pro Phe Phe Leu His Leu Leu Leu He Val Leu Cys Pro Gin His 255 260 265 CCC ACC TGC AGC TGC ATC TTC AAG AAC TTC AAC CTC TTC CTC CTC CTC 866 Pro Thr Cys Ser Cys He Phe Lys Asn Phe Asn Leu Phe Leu Leu Leu 270 275 280 ATC GTC CTC AGC TCC ACT GTT GAC CCC CTC ATC TAT GCT TTC CGC AGC 914 He Val Leu Ser Ser Thr Val Asp Pro Leu He Tyr Ala Phe Arg Ser 285 290 295 300 CAG GAG CTC CGC ATG ACA CTC AAG GAG GTG CTG CTG TGC TCC TGG 959 Gin Glu Leu Arg Met Thr Leu Lys Glu Val Leu Leu Cys Ser Trp 305 310 315 TGATCAGAGG GCGCTGGGCA GAGGGTGACA GTGATATCCA GTGGCCTGCA TCTGTGAGAC 1019 CACAGGTACT CATCCCTTCC TGATCTCCAT TTGTCTAAGG GTCGACAGGA TGAGCTTTAA 1079 AATAGAAACC CAGAGTGCCT GGGGCCAGGA GAAAGGGTAA CTGTGACTGC AGGGCTCACC 1139 CAGGGCAGCT ACGGGAAGTG GAGGAGACAG GGATGGGAAC TCTAGCCCTG AGCAAGGGTC 1199 AGACCACAGG CTCCTGAAGA GCTTCACCTC TCCCCACCTA CAGGCAACTC CTGCTCAAGC 1259 C 1260 (2) INFORMATION FOR SEQ ID NO:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 315 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO : : Met Ser Thr Gin Glu Pro Gin Lys Ser Leu Leu Gly Ser Leu Asn Ser 1 5 10 15 Asn Ala Thr Ser His Leu Gly Leu Ala Thr Asn Gin Ser Glu Pro Trp 20 25 30 Cys Leu Tyr Val Ser He Pro Asp Gly Leu Phe Leu Ser Leu Gly Leu 35 40 45 Val Ser Leu Val Glu Asn Val Leu Val Val He Ala He Thr Lys Asn 50 55 60 Arg Asn Leu His Ser Pro Met Tyr Tyr Phe He Cys Cys Leu Ala Leu 65 70 75 80 Ser Asp Leu Met Val Ser Val Ser He Val Leu Glu Thr Thr He He 85 90 95 Leu Leu Leu Glu Val Gly He Leu Val Ala Arg Val Ala Leu Val Gin 100 105 110 Gin Leu Asp Asn Leu He Asp Val Leu He Cys Gly Ser Met Val Ser 115 120 125 Ser Leu Cys Phe Leu Gly He He Ala He Asp Arg Tyr He Ser He 130 135 140 Phe Tyr Ala Leu Arg Tyr His Ser He Val Thr Leu Pro Arg Ala Arg 145 150 155 160 Arg Ala Val Val Gly He Trp Met Val Ser He Val Ser Ser Thr Leu 165 170 175 Phe He Thr Tyr Tyr Lys His Thr Ala Val Leu Leu Cys Leu Val Thr 180 185 190 Phe Phe Leu Ala Met Leu Ala Leu Met Ala He Leu Tyr Ala His Met 195 200 205 Phe Thr Arg Ala Cys Gin His Val Gin Gly He Ala Gin Leu His Lys 210 215 220 Arg Arg Arg Ser He Arg Gin Gly Phe Cys Leu Lys Gly Ala Ala Thr 225 230 235 240 Leu Thr He Leu Leu Gly He Phe Phe Leu Cys Trp Gly Pro Phe Phe 245 250 255 Leu His Leu Leu Leu He Val Leu Cys Pro Gin His Pro Thr Cys Ser 260 265 270 Cys He Phe Lys Asn Phe Asn Leu Phe Leu Leu Leu He Val Leu Ser 275 280 285 Ser Thr Val Asp Pro Leu He Tyr Ala Phe Arg Ser Gin Glu Leu Arg 290 295 300 Met Thr Leu Lys Glu Val Leu Leu Cys Ser Trp 305 310 315 (2) INFORMATION FOR SEQ ID NO : 5 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1633 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA to mRNA ( ix ) FEATURE : (A) NAME/KEY: 5 ' UTR (B) LOCATION: 1..461 (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 462..1415 (ix) FEATURE: (A) NAME/KEY: 3 ' UTR (B) LOCATION: 1416..1633 (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5: CCCGCATGTG GCCGCCCTCA ATGGAGGGCT CTGAGAACGA CTTTTAAAAC GCAGAGAAAA 60 AGCTCCATTC TTCCCAGACC TCAGCGCAGC CCTGGCCCAG GAAGGGAGGA GACAGAGGCC 120 AGGACGGTCC AGAGGTGTCG AAATGTCCTG GGAACCTGAG CAGCAGCCAC CAGGGAAGAG 180 GCAGGGAGGG AGCTGAGGAC CAGGCTTGGT TGTGAGAATC CCTGAGCCCA GGCGGTTGAT 240 GCCAGGAGGT GTCTGGACTG GCTGGGCCAT GCCTGGGCTG ACCTGTCCAG CCAGGGAGAG 300 GGTGTGAGGG CAGATCTGGG GGTGCCCAGA TGGAAGGAGG CAGGCATGGG GACACCCAAG 360 GCCCCCTGGC AGCACCATGA ACTAAGCAGG ACACCTGGAG GGGAAGAACT GTGGGGACCT 420 GGAGGCCTCC AACGACTCCT TCCTGCTTCC TGGACAGGAC T ATG GCT GTG CAG 473 Met Ala Val Gin 1 GGA TCC CAG AGA AGA CTT CTG GGC TCC CTC AAC TCC ACC CCC ACA GCC 521 Gly Ser Gin Arg Arg Leu Leu Gly Ser Leu Asn Ser Thr Pro Thr Ala 5 10 15 20 ATC CCC CAG CTG GGG CTG GCT GCC AAC CAG ACA GGA GCC CGG TGC CTG 569 He Pro Gin Leu Gly Leu Ala Ala Asn Gin Thr Gly Ala Arg Cys Leu 25 30 35 GAG GTG TCC ATC TCT GAC GGG CTC TTC CTC AGC CTG GGG CTG GTG AGC 617 Glu Val Ser He Ser Asp Gly Leu Phe Leu Ser Leu Gly Leu Val Ser 40 45 50 TTG GTG GAG AAC GCG CTG GTG GTG GCC ACC ATC GCC AAG AAC CGG AAC 665 Leu Val Glu Asn Ala Leu Val Val Ala Thr He Ala Lys Asn Arg Asn 55 60 65 CTG CAC TCA CCC ATG TAC TGC TTC ATC TGC TGC CTG GCC TTG TCG GAC 713 Leu His Ser Pro Met Tyr Cys Phe He Cys Cys Leu Ala Leu Ser Asp 70 75 80 CTG CTG GTG AGC GGG ACG AAC GTG CTG GAG ACG GCC GTC ATC CTC CTG 761 Leu Leu Val Ser Gly Thr Asn Val Leu Glu Thr Ala Val He Leu Leu 85 90 95 100 CTG GAG GCC GGT GCA CTG GTG GCC CGG GCT GCG GTG CTG CAG CAG CTG 809 Leu Glu Ala Gly Ala Leu Val Ala Arg Ala Ala Val Leu Gin Gin Leu 105 110 115 GAC AAT GTC ATT GAC GTG ATC ACC TGC AGC TCC ATG CTG TCC AGC CTC 857 Asp Asn Val He Asp Val He Thr Cys Ser Ser Met Leu Ser Ser Leu 120 125 130 TGC TTC CTG GGC GCC ATC GCC GTG GAC CGC TAC ATC TCC ATC TTC TAC 905 Cys Phe Leu Gly Ala He Ala Val Asp Arg Tyr He Ser He Phe Tyr 135 140 145 GCA CTG CGC TAC CAC AGC ATC GTG ACC CTG CCG CGG GCG CCG CGA GCC 953 Ala Leu Arg Tyr His Ser He Val Thr Leu Pro Arg Ala Pro Arg Ala 150 155 160 GTT GCG GCC ATC TGG GTG GCC AGT GTC GTC TTC AGC ACG CTC TTC ATC 1001 Val Ala Ala He Trp Val Ala Ser Val Val Phe Ser Thr Leu Phe He 165 170 175 180 GGC TAC TAC GAC CAC GTG GCC GTC CTG CTG TGC CTC GTG GTC TTC TTC 1049 Gly Tyr Tyr Asp His Val Ala Val Leu Leu Cys Leu Val Val Phe Phe 185 190 195 CTG GCT ATG CTG GTG CTC ATG GCC GTG CTG GAC GTC CAC ATG CTG GCC 1097 Leu Ala Met Leu Val Leu Met Ala Val Leu Asp Val His Met Leu Ala 200 205 210 CGG GCC TGC CAG CAC GCC CAG GGC ATC GCC CGG CTC CAC AAG AGG CAG 1145 Arg Ala Cys Gin His Ala Gin Gly He Ala Arg Leu His Lys Arg Gin 215 220 225 CGC CCG GTC CAC CAG GGC TTT GGC CTT AAA GGC GCT GTC ACC CTC ACC 1193 Arg Pro Val His Gin Gly Phe Gly Leu Lys Gly Ala Val Thr Leu Thr 230 235 240 ATC CTG CTG GGC ATT TTC TTC CTC TGC TGG GGC CCC TTC TTC CTG CAT 1241 He Leu Leu Gly He Phe Phe Leu Cys Trp Gly Pro Phe Phe Leu His 245 250 255 260 CTC ACA CTC ATC GTC CTC TGC CCC GAG CAC CCC ACG TGC GGC TGC ATC 1289 Leu Thr Leu He Val Leu Cys Pro Glu His Pro Thr Cys Gly Cys He 265 270 275 TTC AAG AAC TTC AAC CTC TTT CTC GCC CTC ATC ATC TGC AAT GCC ATC 1337 Phe Lys Asn Phe Asn Leu Phe Leu Ala Leu He He Cys Asn Ala He 280 285 290 ATC GAC CCC CTC ATC TAC GCC TTC CAC AGC CAG GAG CTC CGC AGG ACG 1385 He Asp Pro Leu He Tyr Ala Phe His Ser Gin Glu Leu Arg Arg Thr 295 300 305 CTC AAG GAG GTG CTG ACA TGC TCC TGG TGA GCGCGGTGCA CGCGCTTTAA 1435 Leu Lys Glu Val Leu Thr Cys Ser Trp * 310 315 GTGTGCTGGG CAGAGGGAGG TGGTGATATT GTGGTCTGGT TCCTGTGTGA CCCTGGGCAG 1495 TTCCTTACCT CCCTGGTCCC CGTTTGTCAA AGAGGATGGA CTAAATGATC TCTGAAAGTG 1555 TTGAAGCGCG GACCCTTCTG GGCAGGGAGG GGTCCTGCAA AACTCCAGGC AGGACTTCTC 1615 ACCAGCAGTC GTGGGAAC 1633 (2) INFORMATION FOR SEQ ID NO : 6 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 317 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 6 : Met Ala Val Gin Gly Ser Gin Arg Arg Leu Leu Gly Ser Leu Asn Ser 1 5 10 15 Thr Pro Thr Ala He Pro Gin Leu Gly Leu Ala Ala Asn Gin Thr Gly 20 25 30 Ala Arg Cys Leu Glu Val Ser He Ser Asp Gly Leu Phe Leu Ser Leu 35 40 45 Gly Leu Val Ser Leu Val Glu Asn Ala Leu Val Val Ala Thr He Ala 50 55 60 Lys Asn Arg Asn Leu His Ser Pro Met Tyr Cys Phe He Cys Cys Leu 65 70 75 80 Ala Leu Ser Asp Leu Leu Val Ser Gly Thr Asn Val Leu Glu Thr Ala 85 90 95 Val He Leu Leu Leu Glu Ala Gly Ala Leu Val Ala Arg Ala Ala Val 100 105 110 Leu Gin Gin Leu Asp Asn Val He Asp Val He Thr Cys Ser Ser Met 115 120 125 Leu Ser Ser Leu Cys Phe Leu Gly Ala He Ala Val Asp Arg Tyr He 130 135 140 Ser He Phe Tyr Ala Leu Arg Tyr His Ser He Val Thr Leu Pro Arg 145 150 155 160 Ala Pro Arg Ala Val Ala Ala He Trp Val Ala Ser Val Val Phe Ser 165 170 175 Thr Leu Phe He Gly Tyr Tyr Asp His Val Ala Val Leu Leu Cys Leu 180 185 190 Val Val Phe Phe Leu Ala Met Leu Val Leu Met Ala Val Leu Asp Val 195 200 205 His Met Leu Ala Arg Ala Cys Gin His Ala Gin Gly He Ala Arg Leu 210 215 220 His Lys Arg Gin Arg Pro Val His Gin Gly Phe Gly Leu Lys Gly Ala 225 230 235 240 Val Thr Leu Thr He Leu Leu Gly He Phe Phe Leu Cys Trp Gly Pro 245 250 255 Phe Phe Leu His Leu Thr Leu He Val Leu Cys Pro Glu His Pro Thr 260 265 270 Cys Gly Cys He Phe Lys Asn Phe Asn Leu Phe Leu Ala Leu He He 275 280 285 Cys Asn Ala He He Asp Pro Leu He Tyr Ala Phe His Ser Gin Glu 290 295 300 Leu Arg Arg Thr Leu Lys Glu Val Leu Thr Cys Ser Trp * 305 310 315 (2) INFORMATION FOR SEQ ID NO : 7 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2012 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA to mRNA (ix) FEATURE: (A) NAME/KEY: 5' UTR (B) LOCATION: 1..693 (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 694..1587 (ix) FEATURE: (A) NAME/KEY: 3 ' UTR (B) LOCATION: 1588..2012 (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 7 : ACAACACTTT ATATATATTT TTATAAATGT AAGGGGTACA AAGGTGCCAT TTTGTTACAT 60 GGATATACCG TGTAGTGGTG AAGCCTGGGC TTTTAGTGTA TCTGTCATCA GAATAACATA 120 CGTGTTACCC ATAGGAATTT CTCATCACCC GCCCCCTCCA CCCTTCGAGT CTCCAATGTC 180 CATTCCACAC TCTATATCCA CGTGTATGCA TATAGCTCCA CATATAAGTG AGAACATGTA 240 GTATTTGACT TCCTCTTTCT GAGTTATTTC ACTTTGATAA TGGCCTCCAC TTCCATCCAT 300 GTTGCTGCAA AAGACATGAC CTTATTCTTT TTGATAGCTG GGGAGTACTC CATTGTGTAT 360 ATGTACCACA TTTCTTTATC CATTCACCCA TTGAGAACAC TTAGTTGATT CCATATCTTT 420 GCTATTGTCA CTAGTGCTGC AATAAACATA CATGTGCAGG CTCCTTCTAA TATACTGATT 480 TATATTTTAT GGAGAGAGAT AGAGTTCTTA GCGAGTGTGC TGTTTATTTC TAGTGTACTT 540 GCAACTAATA TTCTGTATAC TCCCTTTAGG TGATTGGAGA TTTAACTTAG ATCTCCAGCA 600 AGTGCTACAA GAAGAAAAGA TCCTGAAGAA TCAATCAAGT TTCCGTGAAG TCAAGTCCAA 660 GTAACATCCC CGCCTTAACC ACAAGCAGGA GAA ATG AAG CAC ATT ATC AAC TCG 714 Met Lys His He He Asn Ser 1 5 TAT GAA AAC ATC AAC AAC ACA GCA AGA AAT AAT TCC GAC TGT CCT CGT 762 Tyr Glu Asn He Asn Asn Thr Ala Arg Asn Asn Ser Asp Cys Pro Arg 10 15 20 TGT GTT TTG CCG GAG GAG ATA TTT TTC ACA ATT TCC ATT GTT GGA GTT 810 Cys Val Leu Pro Glu Glu He Phe Phe Thr He Ser He Val Gly Val 25 30 35 TTG GAG AAT CTG ATC GTC CTG CTG GCT GTG TTC AAG AAT AAG AAT CTC 858 Leu Glu Asn Leu He Val Leu Leu Ala Val Phe Lys Asn Lys Asn Leu 40 45 50 55 CAG GCA CCC ATG TAC TTT TTC ATC TGT AGC TTG GCC ATA TCT GAT ATG 906 Gin Ala Pro Met Tyr Phe Phe He Cys Ser Leu Ala He Ser Asp Met 60 65 70 CTG GGC AGC CTA TAT AAG ATC TTG GAA AAT ATC CTG ATC ATA TTG AGA 954 Leu Gly Ser Leu Tyr Lys He Leu Glu Asn He Leu He He Leu Arg 75 80 85 AAC ATG GGC ATA CTC AAG CCA CGT GGC AGT TTT GAA ACC ACA GCC CAT 1002 Asn Met Gly He Leu Lys Pro Arg Gly Ser Phe Glu Thr Thr Ala His 90 95 100 GAC ATC ATC GAC TCC CTG TTT CTG CTC TCC CGT CTT GGC TCC ATC TTC 1050 Asp He He Asp Ser Leu Phe Leu Leu Ser Arg Leu Gly Ser He Phe 105 110 115 GAC CTG CTC GTG ATT GCT GCG GAC CGC TAC ATC ACC ATC TTC CAC GCA 1098 Asp Leu Leu Val He Ala Ala Asp Arg Tyr He Thr He Phe His Ala 120 125 130 135 CTG CGG TAC CAC AGC ATC GTG ACC ATG CGC CGC ACT GTG GTG GTG CTT 1146 Leu Arg Tyr His Ser He Val Thr Met Arg Arg Thr Val Val Val Leu 140 145 150 ACG GTC ATC TGG ACG TTC TGC ACG GGG ACT GGC ATC ACC ATG GTG ATC 1194 Thr Val He Trp Thr Phe Cys Thr Gly Thr Gly He Thr Met Val He 155 160 165 TTC TCC CAT CAT GTG CCC CAC GTG ATC ACC TTC ACG TCG CTG TTC CCG 1242 Phe Ser His His Val Pro His Val He Thr Phe Thr Ser Leu Phe Pro 170 175 180 CTG ATG CTG GTC TTC ATC CTG TGC CTC TAT GTG CAC ATG TTC CTG CTG 1290 Leu Met Leu Val Phe He Leu Cys Leu Tyr Val His Met Phe Leu Leu 185 190 195 GCT CGA TGG CAC ACC AGG AAG ATC TCC ACC CTC CCC AGA GCC AAC ATG 1338 Ala Arg Trp His Thr Arg Lys He Ser Thr Leu Pro Arg Ala Asn Met 200 205 210 215 AAA GGG GCC ATG ACA CTG ACC ATC CTG CTC GGG GTC TTC ATC TTC TGC 1386 Lys Gly Ala Met Thr Leu Thr He Leu Leu Gly Val Phe He Phe Cys 220 225 230 TGG GCC CCC TTT GTG CTT CAT GTC CTC TTG ATG ACA TTC TGC CCA AGT 1434 Trp Ala Pro Phe Val Leu His Val Leu Leu Met Thr Phe Cys Pro Ser 235 240 245 AAC CCC TAC TGC GCC TGC TAC ATG TCT CTC TTC CAG GTG AAC GGC ATG 1482 Asn Pro Tyr Cys Ala Cys Tyr Met Ser Leu Phe Gin Val Asn Gly Met 250 255 260 TTG ATC ATG TGC AAT GCC GTC ATT GAC CCC TTC ATA TAT GCC TTC CGG 1530 Leu He Met Cys Asn Ala Val He Asp Pro Phe He Tyr Ala Phe Arg 265 270 275 AGC CCA GAG CTC AGG GAC GCA TTC AAA AAG ATG ATC TTC TGC AGC AGG 1578 Ser Pro Glu Leu Arg Asp Ala Phe Lys Lys Met He Phe Cys Ser Arg 280 285 290 295 TAC TGG TAG AATGGCTGAT CCCTGGTTTT AGAATCCATG GGAATAACGT 1627 Tyr Trp * TGCCAAGTGC CAGAATAGTG TAACATTCCA ACAAATGCCA GTGCTCCTCA CTGGCCTTCC 1687 TTCCCTAATG GATGCAAGGA TGACCCACCA GCTAGTGTTT CTGAATACTA TGGCCAGGAA 1747 CAGTCTATTG TAGGGGCAAC TCTATTTGTG ACTGGACAGA TAAAACGTGT AGTAAAAGAA 1807 GGATAGAATA CAAAGTATTA GGTACAAAAG TAATTAGGTT TGCATTACTT ATGACAAATG 1867 CATTACTTTT GCACCAATCT AGTAAAACAG CAATAAAAAT TCAAGGGCTT TGGGCTAAGG 1927 CAAAGACTTG CTTTCCTGTG GACATTAACA AGCCAGTTCT GAGGCGGCCT TTCCAGGTGG 1987 AGGCCATTGC AGCCAATTTC AGAGT 2012 (2) INFORMATION FOR SEQ ID NO : 8 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 297 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 8 : Met Lys His He He Asn Ser Tyr Glu Asn He Asn Asn Thr Ala Arg 1 5 10 15 Asn Asn Ser Asp Cys Pro Arg Cys Val Leu Pro Glu Glu He Phe Phe 20 25 30 Thr He Ser He Val Gly Val Leu Glu Asn Leu He Val Leu Leu Ala 35 40 45 Val Phe Lys Asn Lys Asn Leu Gin Ala Pro Met Tyr Phe Phe He Cys 50 55 60 Ser Leu Ala He Ser Asp Met Leu Gly Ser Leu Tyr Lys He Leu Glu 65 70 75 80 Asn He Leu He He Leu Arg Asn Met Gly He Leu Lys Pro Arg Gly 85 90 95 Ser Phe Glu Thr Thr Ala His Asp He He Asp Ser Leu Phe Leu Leu 100 105 110 Ser Arg Leu Gly Ser He Phe Asp Leu Leu Val He Ala Ala Asp Arg 115 120 125 Tyr He Thr He Phe His Ala Leu Arg Tyr His Ser He Val Thr Met 130 135 140 Arg Arg Thr Val Val Val Leu Thr Val He Trp Thr Phe Cys Thr Gly 145 150 155 160 Thr Gly He Thr Met Val He Phe Ser His His Val Pro His Val He 165 170 175 Thr Phe Thr Ser Leu Phe Pro Leu Met Leu Val Phe He Leu Cys Leu 180 185 190 Tyr Val His Met Phe Leu Leu Ala Arg Trp His Thr Arg Lys He Ser 195 200 205 Thr Leu Pro Arg Ala Asn Met Lys Gly Ala Met Thr Leu Thr He Leu 210 215 220 Leu Gly Val Phe He Phe Cys Trp Ala Pro Phe Val Leu His Val Leu 225 230 235 240 Leu Met Thr Phe Cys Pro Ser Asn Pro Tyr Cys Ala Cys Tyr Met Ser 245 250 255 Leu Phe Gin Val Asn Gly Met Leu He Met Cys Asn Ala Val He Asp 260 265 270 Pro Phe He Tyr Ala Phe Arg Ser Pro Glu Leu Arg Asp Ala Phe Lys 275 280 285 Lys Met He Phe Cys Ser Arg Tyr Trp * 290 295 (2) INFORMATION FOR SEQ ID NO : 9 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1108 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA to mRNA (ix) FEATURE: (A) NAME/KEY: 5 ' UTR (B) LOCATION: 1..132 ( ix ) FEATURE : (A) NAME/KEY : CDS (B) LOCATION: 133..1026 ( ix) FEATURE : (A) NAME/KEY: 3' UTR (B) LOCATION: 1027..1106 (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 9 : GGGGCCAGAA AGTTCCTGCT TCAGAGCAGA AGATCTTCAG CAAGAACTAC AAAGAAGAAA 60 AGATTCTGGA GAATCAATCA AGTTTCCTGT CAAGTTCCAG TAACGTTTCT GTCTTAACTG 120 CACACAGGAA AG ATG AAA CAC ATT CTC AAT CTG TAT GAA AAC CTC AAC 168 Met Lys His He Leu Asn Leu Tyr Glu Asn Leu Asn 1 5 10 AGT ACA GCA AGA AAT AAC TCA GAC TGT CCT GCT GTG ATT TTG CCA GAA 216 Ser Thr Ala Arg Asn Asn Ser Asp Cys Pro Ala Val He Leu Pro Glu 15 20 25 GAG ATA TTT TTC ACA GTA TCC ATT GTT GGG GTT TTG GAG AAC CTG ATG 264 Glu He Phe Phe Thr Val Ser He Val Gly Val Leu Glu Asn Leu Met 30 35 40 GTC CTT CTG GCT GTG GCC AAG AAT AAG ATG CTT CAG TCG CCC ATG TAC 312 Val Leu Leu Ala Val Ala Lys Asn Lys Met Leu Gin Ser Pro Met Tyr 45 50 55 60 TTT TTC ATC TGC AGC TTG GCT ATT TCC GAT ATG CTG GGG AGC ATG TAC 360 Phe Phe He Cys Ser Leu Ala He Ser Asp Met Leu Gly Ser Met Tyr 65 70 75 AAG ATT TTG GAA AAC GTT CTG ATC ATG TTC AAA AAC ATG GGT TAC CTC 408 Lys He Leu Glu Asn Val Leu He Met Phe Lys Asn Met Gly Tyr Leu 80 85 90 GAG CCT CGA GGC AGT TTT GAA AGC ACA GCA GAT GAT GTG GTG GAC TCC 456 Glu Pro Arg Gly Ser Phe Glu Ser Thr Ala Asp Asp Val Val Asp Ser 95 100 105 CTG TTC ATC CTC TCC CTT CTC GGC TCC ATC TGC AGC CTG TCT GTG ATT 504 Leu Phe He Leu Ser Leu Leu Gly Ser He Cys Ser Leu Ser Val He 110 115 120 GCC GCT GAC CGC TAC ACT ACA ATC TTC CAC GCT CTG CAG TAC CAC CGC 552 Ala Ala Asp Arg Tyr Thr Thr He Phe His Ala Leu Gin Tyr His Arg 125 130 135 140 ATC ATG ACC CCC GCA CCG TGC CCT CGT CAT CTG ACG GTC CTC TGG CGA 600 He Met Thr Pro Ala Pre Cys Pro Arg His Leu Thr Val Leu Trp Arg 145 150 155 GGC TGC ACA GGC AGT GGC ATT ACC ATC GTG ACC TTC TCC CAT CAC GTC 648 Gly Cys Thr Gly Ser Gly He Thr He Val Thr Phe Ser His His Val 160 165 170 CCC ACA GTG ATC GCC TTC ACA GCG CTG TTC CCG CTG ATG CTG GCC TTC 696 Pro Thr Val He Ala Phe Thr Ala Leu Phe Pro Leu Met Leu Ala Phe 175 180 185 ATC CTG TGC CTC TAC GTG CAC ATG TTC CTG CTG GCC CGC TCC CAC ACC 744 He Leu Cys Leu Tyr Val His Met Phe Leu Leu Ala Arg Ser His Thr 190 195 200 AGG AGG ACC CCC TCC CTT CCC AAA GCC AAC ATG AGA GGG GCC GTC ACA 792 Arg Arg Thr Pro Ser Leu Pro Lys Ala Asn Met Arg Gly Ala Val Thr 205 210 215 220 CTG ACT GTC CTG CTC GGG GTC TTC ATT TTC TGT TGG GCA CCC TTT GTC 840 Leu Thr Val Leu Leu Gly Val Phe He Phe Cys Trp Ala Pro Phe Val 225 230 235 CTT CAT GTC CTC TTG ATG ACA TTC TGC CCA GCT GAC CCC TAC TGT GCC 888 Leu His Val Leu Leu Met Thr Phe Cys Pro Ala Asp Pro Tyr Cys Ala 240 245 250 TGC TAC ATG TCC CTC TTC CAG GTG AAT GGT GTG TTG ATC ATG TGT AAT 936 Cys Tyr Met Ser Leu Phe Gin Val Asn Gly Val Leu He Met Cys Asn 255 260 265 GCC ATC ATC GAC CCC TTC ATA TAT GCC TTT CGG AGC CCA GAG CTC AGG 984 Ala He He Asp Pro Phe He Tyr Ala Phe Arg Ser Pro Glu Leu Arg 270 275 280 GTC GCA TTC AAA AAG ATG GTT ATC TGC AAC TGT TAC CAG TAG 1026 Val Ala Phe Lys Lys Met Val He Cys Asn Cys Tyr Gin * 285 290 295 AATGATTGGT CCCTGATTTT AGGAGCCACA GGGATATACT GTCAGGGACA GAGTAGCGTG 1086 ACAGACCAAC AACACTAGGA CT 1108 (2) INFORMATION FOR SEQ ID NO: 10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 297 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10: Met Lys His He Leu Asn Leu Tyr Glu Asn Leu Asn Ser Thr Ala Arg 1 5 10 15 Asn Asn Ser Asp Cys Pro Ala Val He Leu Pro Glu Glu He Phe Phe 20 25 30 Thr Val Ser He Val Gly Val Leu Glu Asn Leu Met Val Leu Leu Ala 35 40 45 Val Ala Lys Asn Lys Met Leu Gin Ser Pro Met Tyr Phe Phe He Cys 50 55 60 Ser Leu Ala He Ser Asp Met Leu Gly Ser Met Tyr Lys He Leu Glu 65 70 75 80 Asn Val Leu He Met Phe Lys Asn Met Gly Tyr Leu Glu Pro Arg Gly 85 90 95 Ser Phe Glu Ser Thr Ala Asp Asp Val Val Asp Ser Leu Phe He Leu 100 105 110 Ser Leu Leu Gly Ser He Cys Ser Leu Ser Val He Ala Ala Asp Arg 115 120 125 Tyr Thr Thr He Phe His Ala Leu Gin Tyr His Arg He Met Thr Pro 130 135 140 Ala Pro Cys Pro Arg His Leu Thr Val Leu Trp Arg Gly Cys Thr Gly 145 150 155 160 Ser Gly He Thr He Val Thr Phe Ser His His Val Pro Thr Val He 165 170 175 Ala Phe Thr Ala Leu Phe Pro Leu Met Leu Ala Phe He Leu Cys Leu 180 185 190 Tyr Val His Met Phe Leu Leu Ala Arg Ser His Thr Arg Arg Thr Pro 195 200 205 Ser Leu Pro Lys Ala Asn Met Arg Gly Ala Val Thr Leu Thr Val Leu 210 215 220 Leu Gly Val Phe He Phe Cys Trp Ala Pro Phe Val Leu His Val Leu 225 230 235 240 Leu Met Thr Phe Cys Pro Ala Asp Pro Tyr Cys Ala Cys Tyr Met Ser 245 250 255 Leu Phe Gin Val Asn Gly Val Leu He Met Cys Asn Ala He He Asp 260 265 270 Pro Phe He Tyr Ala Phe Arg Ser Pro Glu Leu Arg Val Ala Phe Lys 275 280 285 Lys Met Val He Cys Asn Cys Tyr Gin * 290 295 (2) INFORMATION FOR SEQ ID NO: 11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1338 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA to mRNA ( ix) FEATURE : (A) NAME/KEY: 5' UTR (B) LOCATION: 1..297 (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 298..1269 (ix) FEATURE: (A) NAME/KEY: 3'UTR (B) LOCATION: 1270..1338 (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11: GGCTGTAACT GTAGCAACCG GTGTTGGGTG GGGATGAGAA GAGACCAGAG AGAGAGAGGG 60 TCAGAGCGAC AGGGGATGAG ACAGGCTGGT CAGAGTCTGC ACTGATTGTT GGAGACGCAA 120 AGGAAAGTTT TTTCTATGTC TCCAACCTCC CCCTCCTCCC CCGTTTCTCT CTGGAGAAAC 180 TAAAATGTAG ACTGGACAGC ATCCACAAGA GAAGCACCTA GAAGAAGATT TTTTTTTCCC 240 AGCAGCTTGC TCAGGACCCT GCAGGAGCTG CAGCCGGAAC TGGTCCCGCC GATAACC 297 ATG AAC TCT TCC TGC TGC CCG TCC TCC TCT TAT CCG ACG CTG CCT AAC 345 Met Asn Ser Ser Cys Cys Pro Ser Ser Ser Tyr Pro Thr Leu Pro Asn 1 5 10 15 CTC TCC CAG CAC CCT GCA GCC CCC TCT GCC AGC AAC CGG AGT GGC AGT 393 Leu Ser Gin His Pro Ala Ala Pro Ser Ala Ser Asn Arg Ser Gly Ser 20 25 30 GGG TTC TGC GAG CAG GTT TTC ATC AAG CCA GAG GTC TTC CTG GCA CTG 441 Gly Phe Cys Glu Gin Val Phe He Lys Pro Glu Val Phe Leu Ala Leu 35 40 45 GGC ATC GTC AGT CTG ATG GAA AAC ATC CTG GTG ATC CTG GCT GTG GTG 489 Gly He Val Ser Leu Met Glu Asn He Leu Val He Leu Ala Val Val 50 55 60 AGG AAC GGC AAC CTG CAC TCC CCC ATG TAC TTC TTC CTG CTG AGC CTG 537 Arg Asn Gly Asn Leu His Ser Pro Met Tyr Phe Phe Leu Leu Ser Leu 65 70 75 80 CTG CAG GCC GAC CTG CTG GTG AGC CTG TCC AAC TCC CTG GAG ACC ATC 585 Leu Gin Ala Asp Leu Leu Val Ser Leu Ser Asn Ser Leu Glu Thr He 85 90 95 ATG ATC GTG GTT ATC AAC AGC GAC TCC CTG ACC TTG GAG GAC CAA TTC 633 Met He Val Val He Asn Ser Asp Ser Leu Thr Leu Glu Asp Gin Phe 100 105 110 ATC CAG CAC ATG GAC AAC ATC TTC GAC TCT ATG ATC TGC ATC TCC CTG 681 He Gin His Met Asp Asn He Phe Asp Ser Met He Cys He Ser Leu 115 120 125 GTG GCC TCC ATC TGC AAC CTC CTG GCC ATC GCC GTG GAC AGG TAC GTC 729 Val Ala Ser He Cys Asn Leu Leu Ala He Ala Val Asp Arg Tyr Val 130 135 140 ACC ATC TTC TAT GCC CTC CGT TAC CAC AGC ATC ATG ACG GTT AGG AAA 777 Thr He Phe Tyr Ala Leu Arg Tyr His Ser He Met Thr Val Arg Lys 145 150 155 160 GCC CTC TCC TTG ATC GTG GCC ATC TGG GTC TGC TGT GGC ATC TGC GGC 825 Ala Leu Ser Leu He Val Ala He Trp Val Cys Cys Gly He Cys Gly 165 170 175 GTG ATG TTC ATC GTC TAC TCC GAG AGC AAG ATG GTC ATC GTG TGC CTC 873 Val Met Phe He Val Tyr Ser Glu Ser Lys Met Val He Val Cys Leu 180 185 190 ATC ACC ATG TTC TTC GCC ATG GTG CTC CTC ATG GGC ACC CTG TAC ATC 921 He Thr Met Phe Phe Ala Met Val Leu Leu Met Gly Thr Leu Tyr He 195 200 205 CAC ATG TTC CTC TTC GCC AGG CTG CAC GTC CAG CGC ATC GCG GCA CTG 969 His Met Phe Leu Phe Ala Arg Leu His Val Gin Arg He Ala Ala Leu 210 215 220 CCA CCT GCT GAC GGG CTA GCC CCG CAG CAG CAC TCG TGC ATG AAG GGG 1017 Pro Pro Ala Asp Gly Leu Ala Pro Gin Gin His Ser Cys Met Lys Gly 225 230 235 240 GCC GTC ACC ATC ACC ATC CTG CTG GGG GTT TTC ATC TTC TGC TGG GCG 1065 Ala Val Thr He Thr He Leu Leu Gly Val Phe He Phe Cys Trp Ala 245 250 255 CCT TTC TTC CTC CAC CTG GTC CTC ATC ATC ACC TGC CCC ACC AAC CCC 1113 Pro Phe Phe Leu His Leu Val Leu He He Thr Cys Pro Thr Asn Pro 260 265 270 TAC TGC ATC TGC TAC ACG GCG CAC TTC AAC ACC TAC CTG GTT CTC ATC 1161 Tyr Cys He Cys Tyr Thr Ala His Phe Asn Thr Tyr Leu Val Leu He 275 280 285 ATG TGC AAC TCT GTC ATC GAC CCC CTC ATC TAC GCC TTC CGC AGC CTG 1209 Met Cys Asn Ser Val He Asp Pro Leu He Tyr Ala Phe Arg Ser Leu 290 295 300 GAG CTG CGA AAC ACC TTC AAG GAG ATT CTC TGC GGT TGC AAT GGC ATG 1257 Glu Leu Arg Asn Thr Phe Lys Glu He Leu Cys Gly Cys Asn Gly Met 305 310 315 320 AAC GTG GGC TAG GAACCCCCGA GGAGGTGTTC CACGGCTAGC CAAGAGAGAA 1309 Asn Val Gly * AAGCAATGCT CAGGTGAGAC ACAGAAGGG 1338 (2) INFORMATION FOR SEQ ID NO: 12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 323 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 12 : Met Asn Ser Ser Cys Cys Pro Ser Ser Ser Tyr Pro Thr Leu Pro Asn 1 5 10 15 Leu Ser Gin His Pro Ala Ala Pro Ser Ala Ser Asn Arg Ser Gly Ser 20 25 30 Gly Phe Cys Glu Gin Val Phe He Lys Pro Glu Val Phe Leu Ala Leu 35 40 45 Gly He Val Ser Leu Met Glu Asn He Leu Val He Leu Ala Val Val 50 55 60 Arg Asn Gly Asn Leu His Ser Pro Met Tyr Phe Phe Leu Leu Ser Leu 65 70 75 80 Leu Gin Ala Asp Leu Leu Val Ser Leu Ser Asn Ser Leu Glu Thr He 85 90 95 Met He Val Val He Asn Ser Asp Ser Leu Thr Leu Glu Asp Gin Phe 100 105 110 He Gin His Met Asp Asn He Phe Asp Ser Met He Cys He Ser Leu 115 120 125 Val Ala Ser He Cys Asn Leu Leu Ala He Ala Val Asp Arg Tyr Val 130 135 140 Thr He Phe Tyr Ala Leu Arg Tyr His Ser He Met Thr Val Arg Lys 145 150 155 160 Ala Leu Ser Leu He Val Ala He Trp Val Cys Cys Gly He Cys Gly 165 170 175 Val Met Phe He Val Tyr Ser Glu Ser Lys Met Val He Val Cys Leu 180 185 190 He Thr Met Phe Phe Ala Met Val Leu Leu Met Gly Thr Leu Tyr He 195 200 205 His Met Phe Leu Phe Ala Arg Leu His Val Gin Arg He Ala Ala Leu 210 215 220 Pro Pro Ala Asp Gly Leu Ala Pro Gin Gin His Ser Cys Met Lys Gly 225 230 235 240 Ala Val Thr He Thr He Leu Leu Gly Val Phe He Phe Cys Trp Ala 245 250 255 Pro Phe Phe Leu His Leu Val Leu He He Thr Cys Pro Thr Asn Pro 260 265 270 Tyr Cys He Cys Tyr Thr Ala His Phe Asn Thr Tyr Leu Val Leu He 275 280 285 Met Cys Asn Ser Val He Asp Pro Leu He Tyr Ala Phe Arg Ser Leu 290 295 300 Glu Leu Arg Asn Thr Phe Lys Glu He Leu Cys Gly Cys Asn Gly Met 305 310 315 320 Asn Val Gly * (2) INFORMATION FOR SEQ ID NO: 13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 30 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (ix) FEATURE: (A) NAME/KEY: mics_feature (B) LOCATION: 1..30 (D) OTHER INFORMATION: /function = "Degenerate oligonucleotide primer (sense)" (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 13 : GAGTCGACCR CCCATGTAYT DYTTCATCTG 30 (2) INFORMATION FOR SEQ ID NO: 15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1671 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA to mRNA (ix) FEATURE: (A) NAME/KEY: 5 'UTR (B) LOCATION: 1..393 (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 394..1389 (ix) FEATURE: (A) NAME/KEY: 3 ' UTR (B) LOCATION: 1390..1671 (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 15: AGCTTCCGAG AGGCAGCCGA TGTGAGCATG TGCGCACAGA TTCGTCTCCC AATGGCATGG 60 CAGCTTCAAG GAAAATTATT TTGAACAGAC TTGAATGCAT AAGATTAAAG TTAAAGCAGA 120 AGTGAGAACA AGAAAGCAAA GAGCAGACTC TTTCAACTGA GAATGAATAT TTTGAAGCCC 180 AAGATTTTAA CGTGATGATG ATTAGAGTCG TACCTAAAAG AGACTAAAAA CTCCATGTCA 240 AGCTCTGGAC TTGTGACATT TACTCACAGC AGGCATGGCA ATTTTAGCCT CACAACTTTC 300 AGACAGATAA AGACTTGGAG GAAATAACTG AGACGACTCC CTGACCCAGG AGGTTAAATC 360 AATTCAGGGG GACACTGGAA TTCTCCTGCC AGC ATG GTG AAC TCC ACC CAC CGT 414 Met Val Asn Ser Thr His Arg 1 5 GGG ATG CAC ACT TCT CTG CAC CTC TGG AAC CGC AGC AGT TAC AGA CTG 462 Gly Met His Thr Ser Leu His Leu Trp Asn Arg Ser Ser Tyr Arg Leu 10 15 20 CAC AGC AAT GCC AGT GAG TCC CTT GGA AAA GGC TAC TCT GAT GGA GGG 510 His Ser Asn Ala Ser Glu Ser Leu Gly Lys Gly Tyr Ser Asp Gly Gly 25 30 35 TGC TAC GCG CAA CTT TTT GTC TCT CCT GAG GTG TTT GTG ACT CTG GGT 558 Cys Tyr Ala Gin Leu Phe Val Ser Pro Glu Val Phe Val Thr Leu Gly 40 45 50 55 GTG ATC AGC TTG TTG GAG AAT ATC TTA GAG ATT GTG GCA ATA GCC AAG 606 Val He Ser Leu Leu Glu Asn He Leu Glu He Val Ala He Ala Lys 60 65 70 AAC AAG AAT CTG CAT TCA CCC ATG TAC TTT TTC ATC TGC AGC TTG GCT 654 Asn Lys Asn Leu His Ser Pro Met Tyr Phe Phe He Cys Ser Leu Ala 75 80 85 GTG GCT GAT ATG CTG GTG AGC GTT TCA AAT GGA TCA GAA ACC ATT ATC 702 Val Ala Asp Met Leu Val Ser Val Ser Asn Gly Ser Glu Thr He He 90 95 100 ATC ACC CTA TTA AAC CGT ACA GAT ACG GAT GCA CAG AGT TTC ACA GTG 750 He Thr Leu Leu Asn Arg Thr Asp Thr Asp Ala Gin Ser Phe Thr Val 105 110 115 AAT ATT GAT AAT GTC ATT GAC TCG GTG ATC TGT AGC TCC TTG CTT GCA 798 Asn He Asp Asn Val He Asp Ser Val He Cys Ser Ser Leu Leu Ala 120 125 130 135 TCC ATT TGC AGC CTG CTT TCA ATT GCA GTG GAC AGG TAC TTT ACT ATC 846 Ser He Cys Ser Leu Leu Ser He Ala Val Asp Arg Tyr Phe Thr He 140 145 150 TTC TAT GCT CTC CAG TAC CAT AAC ATT ATG ACA GTT AAG CGG GTT GGG 894 Phe Tyr Ala Leu Gin Tyr His Asn He Met Thr Val Lys Arg Val Gly 155 160 165 ATC AGC ATA AGT TGT ATC TGG GCA GCT TGC ACG GTT TCA GGT ATT TTG 942 He Ser He Ser Cys He Trp Ala Ala Cys Thr Val Ser Gly He Leu 170 175 180 TTC ATC ATT TAC TCA GAT AGT AGT GCT GTC ATC ATC TGC CTC ATC ACC 990 Phe He He Tyr Ser Asp Ser Ser Ala Val He He Cys Leu He Thr 185 190 195 ATG TTC TTC ACC ATG CTG GCT CTC ATG GCT TCT CTC TAT GTC CAC CTG 1038 Met Phe Phe Thr Met Leu Ala Leu Met Ala Ser Leu Tyr Val His Leu 200 205 210 215 TTC CTG ATG GCC AGG CTT CAC ATT AAG AGG ATT GCT GTC CTC CCC GGC 1086 Phe Leu Met Ala Arg Leu His He Lys Arg He Ala Val Leu Pro Gly 220 225 230 ACT GGT GCC ATC CGC CAA GGT GCC AAT ATG AAG GGA GCG ATT ACC TTG 1134 Thr Gly Ala He Arg Gin Gly Ala Asn Met Lys Gly Ala He Thr Leu 235 240 245 ACC ATC CTG ATT GGC GTC TTT GTT GTC TGC TGG GCC CCA TTC TTC CTC 1182 Thr He Leu He Gly Val Phe Val Val Cys Trp Ala Pro Phe Phe Leu 250 255 260 CAC TTA ATA TTC TAC ATC TCT TGT CCT CAG AAT CCA TAT TGT GTG TGC 1230 His Leu He Phe Tyr He Ser Cys Pro Gin Asn Pro Tyr Cys Val Cys 265 270 275 TTC ATG TCT CAC TTT AAC TTG TAT CTC ATA CTG ATC ATG TGT AAT TCA 1278 Phe Met Ser His Phe Asn Leu Tyr Leu He Leu He Met Cys Asn Ser 280 285 290 295 ATC ATC GAT CCT CTG ATT TAT GCA CTC CGG AGT CAA GAA CTG AGG AAA 1326 He He Asp Pro Leu He Tyr Ala Leu Arg Ser Gin Glu Leu Arg Lys 300 305 310 ACC TTC AAA GAG ATC ATC TCT TCC TAT CCC CTG GGA GGC CTT TGT GAC 1374 Thr Phe Lys Glu He He Ser Ser Tyr Pro Leu Gly Gly Leu Cys Asp 315 320 325 TTG TCT AGC AGA TAT TAAATGGGGA CAGAGCACGC AATATAGGAA CATCCATAAG 1429 Leu Ser Ser Arg Tyr 330 AGACTTTTTC ACTCTTACCC TACCTGAATA TTCTACTTCT GCAACAGCTT TCTCTTCCGT 1489 GTAGGGTACT GGTTGAGATA TCCATTGTGT AAATTTAAGC CTATGATTTT TAATGAGAAA 1549 AAATGCCCAG TCTCTGTATT ATTTCCAATC TCATGCTACT TTTTTGGCCA TAAAATATGA 1609 ATCTATGTTA TAGGTTGTAG GCACTGTGGA TTTACAAAAA GAAAAGTCCT TATTAAAAGA 1669 TT 1671 (2) INFORMATION FOR SEQ ID NO: 16: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 332 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 16: Met Val Asn Ser Thr His Arg Gly Met His Thr Ser Leu His Leu Trp 1 5 10 15 sn Arg Ser Ser Tyr Arg Leu His Ser Asn Ala Ser Glu Ser Leu Gly 20 25 30 Lys Gly Tyr Ser Asp Gly Gly Cys Tyr Ala Gin Leu Phe Val Ser Pro 35 40 45 Glu Val Phe Val Thr Leu Gly Val He Ser Leu Leu Glu Asn He Leu 50 55 60 Glu He Val Ala He Ala Lys Asn Lys Asn Leu His Ser Pro Met Tyr 65 70 75 80 Phe Phe He Cys Ser Leu Ala Val Ala Asp Met Leu Val Ser Val Ser 85 90 95 Asn Gly Ser Glu Thr He He He Thr Leu Leu Asn Arg Thr Asp Thr 100 105 110 Asp Ala Gin Ser Phe Thr Val Asn He Asp Asn Val He Asp Ser Val 115 120 125 He Cys Ser Ser Leu Leu Ala Ser He Cys Ser Leu Leu Ser He Ala 130 135 140 Val Asp Arg Tyr Phe Thr He Phe Tyr Ala Leu Gin Tyr His Asn He 145 150 155 160 Met Thr Val Lys Arg Val Gly He Ser He Ser Cys He Trp Ala Ala 165 170 175 Cys Thr Val Ser Gly He Leu Phe He He Tyr Ser Asp Ser Ser Ala 180 185 190 Val He He Cys Leu He Thr Met Phe Phe Thr Met Leu Ala Leu Met 195 200 205 Ala Ser Leu Tyr Val His Leu Phe Leu Met Ala Arg Leu His He Lys 210 215 220 Arg He Ala Val Leu Pro Gly Thr Gly Ala He Arg Gin Gly Ala Asn 225 230 235 240 Met Lys Gly Ala He Thr Leu Thr He Leu He Gly Val Phe Val Val 245 250 255 Cys Trp Ala Pro Phe Phe Leu His Leu He Phe Tyr He Ser Cys Pro 260 265 270 Gin Asn Pro Tyr Cys Val Cys Phe Met Ser His Phe Asn Leu Tyr Leu 275 280 285 He Leu He Met Cys Asn Ser He He Asp Pro Leu He Tyr Ala Leu 290 295 300 Arg Ser Gin Glu Leu Arg Lys Thr Phe Lys Glu He He Ser Ser Tyr 305 310 315 320 Pro Leu Gly Gly Leu Cys Asp Leu Ser Ser Arg Tyr 325 330 (2) INFORMATION FOR SEQ ID NO: 17: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 978 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..975 ( i) SEQUENCE DESCRIPTION: SEQ ID NO: 17: ATG AAC TCC TCC TCC ACC CTG ACT GTA TTG AAT CTT ACC CTG AAC GCC 48 Met Asn Ser Ser Ser Thr Leu Thr Val Leu Asn Leu Thr Leu Asn Ala 1 5 10 15 TCA GAG GAT GGC ATT TTA GGA TCA AAT GTC AAG AAC AAG TCT TTG GCC 96 Ser Glu Asp Gly He Leu Gly Ser Asn Val Lys Asn Lys Ser Leu Ala 20 25 30 TGT GAA GAA ATG GGC ATT GCC GTG GAG GTG TTC CTG ACC CTG GGT CTC 144 Cys Glu Glu Met Gly He Ala Val Glu Val Phe Leu Thr Leu Gly Leu 35 40 45 GTC AGC CTC TTA GAG AAC ATC CTG GTC ATT GGG GCC ATA GTA AAG AAC 192 Val Ser Leu Leu Glu Asn He Leu Val He Gly Ala He Val Lys Asn 50 55 60 AAA AAC CTG CAC TCA CCC ATG TAC TTC TTT GTG GGC AGC TTA GCC GTG 240 Lys Asn Leu His Ser Pro Met Tyr Phe Phe Val Gly Ser Leu Ala Val 65 70 75 80 GCC GAC ATG CTG GTG AGC ATG TCC AAT GCC TGG GAG ACT GTC ACC ATA 288 Ala Asp Met Leu Val Ser Met Ser Asn Ala Trp Glu Thr Val Thr He 85 90 95 TAC TTG CTA AAT AAT AAA CAC CTG GTG ATA GCC GAC ACC TTT GTG CGA 336 Tyr Leu Leu Asn Asn Lys His Leu Val He Ala Asp Thr Phe Val Arg 100 105 110 CAC ATC GAC AAC GTG TTC GAC TCC ATG ATC TGC ATC TCT GTG GTG GCC 384 His He Asp Asn Val Phe Asp Ser Met He Cys He Ser Val Val Ala 115 120 125 TCG ATG TGC AGT TTG CTG GCC ATT GCG GTG GAT AGG TAC ATC ACC ATC 432 Ser Met Cys Ser Leu Leu Ala He Ala Val Asp Arg Tyr He Thr He 130 135 140 TTC TAT GCC TTG CGC TAC CAC CAC ATC ATG ACC GCG AGG CGC TCG GGG 480 Phe Tyr Ala Leu Arg Tyr His His He Met Thr Ala Arg Arg Ser Gly 145 150 155 160 GTG ATC ATC GCC TGC ATT TGG ACC TTC TGC ATA AGC TGC GGC ATT GTT 528 Val He He Ala Cys He Trp Thr Phe Cys He Ser Cys Gly He Val 165 170 175 TTC ATC ATC TAC TAT GAG TCC AAG TAT GTG ATC ATT TGC CTC ATC TCC 576 Phe He He Tyr Tyr Glu Ser Lys Tyr Val He He Cys Leu He Ser 180 185 190 ATG TTC TTC ACC ATG CTG TTC TTC ATG GTG TCT CTG TAT ATA CAC ATG 624 Met Phe Phe Thr Met Leu Phe Phe Met Val Ser Leu Tyr He His Met 195 200 205 TTC CTC CTG GCC CGG AAC CAT GTC AAG CGG ATA GCA GCT TCC CCC AGA 672 Phe Leu Leu Ala Arg Asn His Val Lys Arg He Ala Ala Ser Pro Arg 210 215 220 TAC AAC TCC GTG AGG CAA AGG ACC AGC ATG AAG GGG GCT ATT ACC CTC 720 Tyr Asn Ser Val Arg Gin Arg Thr Ser Met Lys Gly Ala He Thr Leu 225 230 235 240 ACC ATG CTA CTG GGG ATT TTC ATT GTC TGC TGG TCT CCC TTC TTT CTT 768 Thr Met Leu Leu Gly He Phe He Val Cys Trp Ser Pro Phe Phe Leu 245 250 255 CAC CTT ATC TTA ATG ATC TCC TGC CCT CAG AAC GTC TAC TGC TCT TGC 816 His Leu He Leu Met He Ser Cys Pro Gin Asn Val Tyr Cys Ser Cys 260 265 270 TTT ATG TCT TAC TTC AAC ATG TAC CTT ATA CTC ATC ATG TGC AAC TCC 864 Phe Met Ser Tyr Phe Asn Met Tyr Leu He Leu He Met Cys Asn Ser 275 280 285 GTG ATC GAT CCT CTC ATC TAC GCC CTC CGC AGC CAA GAG ATG CGG AGG 912 Val He Asp Pro Leu He Tyr Ala Leu Arg Ser Gin Glu Met Arg Arg 290 295 300 ACC TTT AAG GAG ATC GTC TGT TGT CAC GGA TTC CGG CGA CCT TGT AGG 960 Thr Phe Lys Glu He Val Cys Cys His Gly Phe Arg Arg Pro Cys Arg 305 310 315 320 CTC CTT GGC GGG TAT TAA 978 Leu Leu Gly Gly Tyr 325 (2) INFORMATION FOR SEQ ID NO: 18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 325 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 18: Met Asn Ser Ser Ser Thr Leu Thr Val Leu Asn Leu Thr Leu Asn Ala 1 5 10 15 Ser Glu Asp Gly He Leu Gly Ser Asn Val Lys Asn Lys Ser Leu Ala 20 25 30 Cys Glu Glu Met Gly He Ala Val Glu Val Phe Leu Thr Leu Gly Leu 35 40 45 Val Ser Leu Leu Glu Asn He Leu Val He Gly Ala He Val Lys Asn 50 55 60 Lys Asn Leu His Ser Pro Met Tyr Phe Phe Val Gly Ser Leu Ala Val 65 70 75 80 Ala Asp Met Leu Val Ser Met Ser Asn Ala Trp Glu Thr Val Thr He 85 90 95 Tyr Leu Leu Asn Asn Lys His Leu Val He Ala Asp Thr Phe Val Arg 100 105 110 His He Asp Asn Val Phe Asp Ser Met He Cys He Ser Val Val Ala 115 120 125 Ser Met Cys Ser Leu Leu Ala He Ala Val Asp Arg Tyr He Thr He 130 135 140 Phe Tyr Ala Leu Arg Tyr His His He Met Thr Ala Arg Arg Ser Gly 145 150 155 160 Val He He Ala Cys He Trp Thr Phe Cys He Ser Cys Gly He Val 165 170 175 Phe He He Tyr Tyr Glu Ser Lys Tyr Val He He Cys Leu He Ser 180 185 190 Met Phe Phe Thr Met Leu Phe Phe Met Val Ser Leu Tyr He His Met 195 200 205 Phe Leu Leu Ala Arg Asn His Val Lys Arg He Ala Ala Ser Pro Arg 210 215 220 Tyr Asn Ser Val Arg Gin Arg Thr Ser Met Lys Gly Ala He Thr Leu 225 230 235 240 Thr Met Leu Leu Gly He Phe He Val Cys Trp Ser Pro Phe Phe Leu 245 250 255 His Leu He Leu Met He Ser Cys Pro Gin Asn Val Tyr Cys Ser Cys 260 265 270 Phe Met Ser Tyr Phe Asn Met Tyr Leu He Leu He Met Cys Asn Ser 275 280 2Θ5 Val He Asp Pro Leu He Tyr Ala Leu Arg Ser Gin Glu Met Arg Arg 290 295 300 Thr Phe Lys Glu He Val Cys Cys His Gly Phe Arg Arg Pro Cys Arg 305 310 315 320 Leu Leu Gly Gly Tyr 325 (2) INFORMATION FOR SEQ ID NO: 19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 30 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (ix) FEATURE: (A) NAME/KEY: misc_feature (B) LOCATION: 1..32 (D) OTHER INFORMATION: /function = "Degenerate oligonucleotide primer (antisense) " (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 19: GAATTCGACG TCACAGTATG ACGGCCATGG 30

Claims: WHAT WE CLAIM IS: 1. A method for characterizing a compound as an agonist of a mammalian melanocortin receptor, the method comprising the steps of: (a) providing a panel comprising a first mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the α-MSH receptor, a second mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the ACTH receptor, a third mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-3 receptor, a fourth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-4 receptor, and a fifth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-5 receptor, wherein each mammalian cell expresses the melanocortin receptor encoded by the recombinant expression construct comprising the cell; (b) contacting each of the cells of the panel with a test compound to be characterized as an agonist of a mammalian melanocortin receptor; (c) detecting binding of the test compound to each of the mammalian melanocortin receptors by assaying for a metabolite produced in the cells that bind the compound. 2. The method of claim 1 , wherein the metabolite detected in subpart (c) is cyclic AMP. 3. The method of claim 1 , each of the cells further comprising a recombinant expression construct encoding a cyclic AMP responsive element (CRE) transcription factor binding site operatively linked to a nucleic acid sequence encoding a protein capable of producing a detectable metabolite. 4. The method of claim 3, wherein the nucleic acid sequence encodes β- galactosidase. 5. The method of claim 3, wherein the recombinant expression construct is pCRE/β-galactosidase. 6. The method of claim 3, wherein the detectable metabolite produced by the protein encoded by the recombinant expression construct is produced by binding of the test compound to the mammalian melanocortin receptor encoded by each of the cells of the panel. 7. A method for characterizing a compound as an antagonist of a mammalian melanocortin receptor, the method comprising the steps of: (a) providing a panel comprising a first mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the α-MSH receptor, a second mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the ACTH receptor, a third mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-3 receptor, a fourth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-4 receptor, and a fifth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-5 receptor, wherein each mammalian cell expresses the melanocortin receptor encoded by the recombinant expression construct comprising the cell; (b) contacting each of the cells of the panel with an agonist of the mammalian melanocortin receptor in an amount sufficient to produce a detectable amount of a metabolite produced in the cells that bind the agonist, in the presence or absence of a test compound to be characterized as an antagonist of a mammalian melanocortin receptor; (c) detecting the amount of the metabolite produced in each cell in the panel in the presence of the test compound with the amount of the metabolite produced in each cell in the panel in the absence. 8. The method of claim 7, wherein the metabolite detected in subpart (c) is cyclic AMP. 9. The method of claim 7, each of the cells further comprising a recombinant expression construct encoding a cyclic AMP responsive element (CRE) transcription factor binding site operatively linked to a nucleic acid sequence encoding a protein capable of producing a detectable metabolite. 10. The method of claim 9, wherein the nucleic acid sequence encodes β- galactosidase. 1 1. The method of claim 9, wherein the recombinant expression construct is pCRE/β-galactosidase. 12. The method of claim 9, wherein the detectable metabolite produced by the protein encoded by the recombinant expression construct is produced by binding of the test compound to the mammalian melanocortin receptor encoded by each of the cells of the panel. 13. The method of claim 1 wherein the test compound is an agonist of the MC-3 mammalian melanocortin receptor. 14. The method of claim 1 wherein the test compound is an agonist of the MC-4 mammalian melanocortin receptor. 15. The method of claim 3 wherein the test compound is an agonist of the MC-3 mammalian melanocortin receptor. 16. The method of claim 3 wherein the test compound is an agonist of the MC-4 mammalian melanocortin receptor. 17. The method of claim 7 wherein the test compound is an antagonist of the MC-3 mammalian melanocortin receptor. 18. The method of claim 7 wherein the test compound is an antagonist of the MC-4 mammalian melanocortin receptor. 19. The method of claim 9 wherein the test compound is an antagonist of the MC-3 mammalian melanocortin receptor. 20. The method of claim 9 wherein the test compound is an antagonist of the MC-4 mammalian melanocortin receptor. 21. A mammalian melanocortin MC-3 receptor agonist according to claims 13 or 15. 22. A mammalian melanocortin MC-4 receptor agonist according to claims 14 or 16. 23. A mammalian melanocortin MC-3 receptor antagonist according to claims 17 or 19. 24. A mammalian melanocortin MC-4 receptor antagonist according to claims 18 or 20. 25. A method of inhibiting feeding behavior in an animal, the method comprising administering an effective amount of a mammalian melanocortin MC-3 or MC-4 receptor agonist according to claim 21. 26. A method of stimulating feeding behavior in an animal, the method comprising administering an effective amount of a mammalian melanocortin MC-3 or MC-4 receptor antagonist according to claim 24. 27. A method for characterizing a mammalian melanocortin MC-3 or MC-4 receptor agonist as an inhibitor of feeding behavior in an animal, the method comprising: (a) providing food to an animal that has been deprived of food for at least 12 hours with or without administering to the animal a mammalian melanocortin MC-3 or MC-4 receptor agonist according to claim 25; and (b) comparing the amount of food eaten by the animal with and without administration of the mammalian melanocortin MC-3 or MC-4 receptor agonist. 28. A method for characterizing a mammalian melanocortin MC-3 or MC-4 receptor antagonist as a stimulator of feeding behavior in an animal, the method comprising: (a) providing food to an animal that has not been otherwise deprived of food for at least 12 hours, with or without administering to the animal a mammalian melanocortin MC-3 or MC-4 receptor antagonist according to claim 26 immediately prior to the onset of darkness or nighttime; and (b) comparing the amount of food eaten by the animal with and without administration of the mammalian melanocortin MC-3 or MC-4 receptor antagonist. 29. A mammalian melanocortin MC-3 or MC-4 receptor agonist having the general formula: A-B-C-D-E-F-G-amide wherein A is Leu, He, Nle, Met, or substituted analogues thereof; B is Asp, Glu , or substituted analogues thereof; C is His or substituted analogues thereof; D is D-Phe, D-Tyr or substituted analogues thereof; E is Arg, Lys, homoArg, homoLys, or substituted analogues thereof; F is Trp or substituted analogues thereof; G is Lys, homoLys or substituted analogues thereof; and wherein the peptide is cyclized by the formation of an amide bond between the side chain carboxyl group of the Asp or Glu residue at position B in the peptide, and the side chain amino group of the Lys or homoLys residue at position G. 30. A mammalian melanocortin MC-3 or MC-4 receptor antagonist having the general formula: A-B-C-D-E-F-G-amide wherein A is Leu, lie, Nle, Met, or substituted analogues thereof; B is Asp, Glu or substituted analogues thereof; C is His or substituted analogues thereof; D is D-Nal or substituted analogues thereof; E is Arg, Lys, homoArg, homoLys or substituted analogues thereof; F is Trp or substituted analogues thereof; G is Lys, homoLys or substituted analogues thereof; and wherein the peptide is cyclized by the formation of an amide bond between the side chain carboxyl group of the Asp or Glu residue at position B in the peptide, and the side chain amino group of the Lys or homoLys residue at position G. 31. A biological screening panel for determining the receptor agonist/antagonist profile of a test compound, the panel comprising a first mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the α-MSH receptor, a second mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the ACTH receptor, a third mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-3 receptor, a fourth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-4 receptor, and a fifth mammalian cell comprising a recombinant expression construct encoding a mammalian melanocortin receptor that is the MC-5 receptor, wherein each mammalian cell expresses the melanocortin receptor encoded by the recombinant expression construct comprising the cell.

Inventors: BOSTON BRUCE A, CHEN WENBIAO, CONE ROGER D, FAN WEI, KESTERTON ROBERT A, LU DONGSI, BOSTON, BRUCE, A., CHEN, WENBIAO, CONE, ROGER, D., FAN, WEI, KESTERTON, ROBERT, A., LU, DONGSI
Applicants: BOSTON BRUCE A, CHEN WENBIAO, CONE ROGER D, FAN WEI, KESTERTON ROBERT A, LU DONGSI, UNIV OREGON HEALTH SCIENCES, BOSTON, BRUCE, A., CHEN, WENBIAO, CONE, ROGER, D., FAN, WEI, KESTERTON, ROBERT, A., LU, DONGSI, OREGON HEALTH SCIENCES UNIVERSITY
Application year: 1997
Main classification: C12N15
IPC codes: A61K38, A61K45, A61P3, A61P43, C07K7, C07K14, C12N5, C12N15, C12P21, C12Q1, G01N33