Gene encoding G-protein coupled receptor and gene product thereof

A DNA selected from the following group consisting of:

• (i) a DNA consisting of a base sequence represented by SEQ ID NO:
• 1, 15, or 17 of the sequence listing, or a complementary strand thereof;
• (ii) a DNA comprising the DNA of (i) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof;
• (iii) a DNA comprising a base sequence having a variation including a deletion, a substitution and an addition of one to several nucleotides in the base sequence of the DNA of (i) or (ii) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof;
• (iv) a DNA having homology of at least 70% with the base sequence of the DNA according to any one of (i) to (iii) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof;
• and
• (v) a DNA hybridizing under stringent condition with the DNA according to any one of (i) to (iv) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof,
• wherein the equivalent function to a G-protein coupled receptor is an equivalent function to a G-protein coupled receptor that is caused by binding with a ligand, which is a peptide selected from the following group consisting of:
• (a) cholecystokinin octapeptide sulfated form (SEQ ID NO:
• 14, hereunder abbreviated as “CCK-8S”);
• (b) a peptide comprising an amino acid sequence having a variation including a deletion, a substitution and an addition of one to several amino acids in the amino acid sequence of CCK-8S and having an equivalent function to CCK-8S;
• and
• (c) a peptide comprising the peptide of (a) or (b) and having an equivalent function to CCK-8S.

A protein selected from the following group consisting of:

• (vi) a protein consisting of an amino acid sequence represented by SEQ ID NO:
• 2, 16, or 18 of the sequence listing;
• (vii) a protein comprising the protein of (vi) and having an equivalent function to a G-protein coupled receptor;
• and
• (viii) a protein comprising an amino acid sequence having a variation including a deletion, a substitution and an addition of one to several amino acid in the amino acid sequence of the protein of (vi) or (vii), and having an equivalent function to a G-protein coupled receptor.

A protein selected from the following group consisting of:

• (vi) a protein consisting of an amino acid sequence represented by SEQ ID NO:
• 2, 16, or 18 of the sequence listing;
• (vii) a protein comprising the protein of (vi) and having an equivalent function to a G-protein coupled receptor;
• (viii) a protein comprising an amino acid sequence having a variation including a deletion, a substitution and an addition of one to several amino acid in the amino acid sequence of the protein of (vi) or (vii), and having an equivalent function to a G-protein coupled receptor;
• and
• (ix) a protein having homology of at least 70% with the amino acid sequence of the protein according to any one of (vi) to (viii) and having an equivalent function to a G-protein coupled receptor,
• wherein the equivalent function to a G-protein coupled receptor is an equivalent function to a G-protein coupled receptor that is caused by binding with a ligand, which is a peptide selected from the following group consisting of:
• (a) cholecystokinin octapeptide sulfated form (SEQ ID NO:
• 14, hereunder abbreviated as “CCK-8S”);
• (b) a peptide comprising an amino acid sequence having a variation including a deletion, a substitution and an addition of one to several amino acids in the amino acid sequence of CCK-8S and having an equivalent function to CCK-8S;
• and
• (c) a peptide comprising the peptide of (a) or (b) and having an equivalent function to CCK-8S.

A method for identifying a compound that has an anti-depressant action, comprising contacting a test compound with a cell containing a DNA selected from the following group consisting of:

• (i) a DNA consisting of a base sequence represented by SEQ ID NO:
• 1, 15, or 17 of the sequence listing, or a complementary strand thereof;
• (ii) a DNA comprising the DNA of (i) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof;
• (iii) a DNA comprising a base sequence having a variation including a deletion, a substitution and an addition of one to several nucleotides in the base sequence of the DNA of (i) or (ii) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof;
• (iv) a DNA having homology of at least 70% with the base sequence of the DNA according to any one of (i) to (iii) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof;
• and
• (v) a DNA hybridizing under stringent condition with the DNA according to any one of (i) to (iv) and encoding a protein having an equivalent function to a G-protein coupled receptor, or a complementary strand thereof,
• measuring a function of a protein encoded by the DNA and expressed on a cell membrane of the cell, and determining by comparing with a case where the cell is not made to contact with a test compound that a test compound that reduces or eliminates the function of the protein is to be a compound having anti-depressant action.