CDNA CLONING OF A PUTATIVE G-PROTEIN-COUPLED RECEPTOR FROM BRAIN

Using degenerate oligonucleotide primers corresponding to conserved re gions of the G-protein coupled receptor superfamily, we carried out a low-stringency polymerase chain reaction and obtained two novel partia l-length clones from a rat brain cDNA library. We used one of these cl ones for conventional library screening and isolated a longer cDNA clo ne, designated as RBU-15, from another rat brain library. Although RBU -15 was truncated at its 5' end, Northern blot analysis revealed that the gene was expressed in the brain and spleen. Next, we isolated a fu ll-length cDNA clone, designated as HB-954, from a human fetal brain l ibrary, using RBU-15 as a probe. The deduced amino acid sequence of HB -954 contained four putative glycosylation sites in the N-terminal par t, seven transmembrane domains, and a large cytosolic domain in the C- terminal part. The protein products of RBU-15 and HB-954 likely belong to a distinctive subfamily, because no receptors in the superfamily w ere found to be closely related to them.