Cloning, characterization, and chromosomal localization of rec1.3, a member of the G-protein-coupled receptor family highly expressed in brain.

During a project to identify G-protein-coupled receptors (GPCR) expressed within taste buds, we have isolated a novel receptor-like sequence. The full length sequence of this receptor (rec1.3) has been obtained in both cow and mouse. Rec1.3 bears little sequence similarity to any GPCR whose ligand is known: the closest identity (33%) is to the orphan receptor edg-1. In cow, rec1.3 is expressed most prominently in the brain, with moderate expression in testis and tongue; in the mouse the expression is more widespread. No specific binding for a range of ligands was detected when the mouse coding sequence was expressed in eukaryotic cells. In situ hybridization showed that rec1.3 is widely expressed throughout the mouse brain and is highly expressed in localized regions of the hindbrain, midbrain and hypothalamus. The rec1.3 gene was localized to the centromeric region of chromosome 4 in mouse, a region associated with neonatal seizures.