MOLECULAR-CLONING OF A NOVEL CANDIDATE G-PROTEIN-COUPLED RECEPTOR FROM RAT-BRAIN

A PCR cloning strategy using primers designed from sequences selective ly conserved among a cannabinoid receptor and two orphan receptors, wa s used to isolate novel G protein-coupled receptors. rCNL3, a 1.75 kb cDNA encoding a 363 amino acid protein, was isolated from a rat cerebr al cortex library. Sequence analysis showed that rCNL3 possesses a num ber of structural characteristics of G protein-coupled receptors and h as 61% amino acid identity (from transmembrane region one through the carboxyl-terminus) with two other candidate G protein-coupled receptor s. Therefore, these three receptors may comprise a receptor subfamily with identical or closely related endogenous ligands. Northern and in situ hybridization experiments demonstrated that rCNL3 mRNA is express ed in the rat brain, with a prominent distribution in striatum.