Cloning of a cDNA encoding a novel putative G-protein-coupled receptor expressed in specific rat brain regions

A cDNA clone encoding a novel putative G-protein-coupled receptor was isolated from a rat brain cDNA library using a PCR-amplified cDNA fragment as a hybridization probe. The 3,615-bp-long nucleotide sequence predicts a single open reading frame of 1,173 bp coding for 391 amino acids, giving a calculated molecular weight of 42.75 kD. The amino acid sequence shares features common to many other receptors, including the seven membrane-spanning hydrophobic regions and putative asparagine-linked glycosylation and phosphorylation sites. Northern blot analysis reveals that a corresponding approximately 3.7-kb mRNA is expressed in specific brain regions such as hypothalamus, cortex, hippocampus, and thalamus but not in other organs analyzed. Although the ligand for this receptor has not yet been identified, it shares some similarities with the vascular type-1 angiotensin II receptor, the vasoactive intestinal peptide (VIP) receptor, and the chemotactic receptors for human C5a anaphylatoxin and the formyl peptide fMet-Leu-Phe.