Differential display screening for region-specific transcripts in rat brain revealed a novel striatum-specific transcript encoding an orphan G-protein-coupled receptor (GPCR) designated Strg/Gpr88 for striatum-specific GPCR. We isolated its homologues from human (HGMW-approved symbol GPR88) and mouse and mapped them to chromosomes 1p21.3 and 3G1, respectively. These loci are syntenic to each other, thereby suggesting their orthology. The predicted primary sequences of Strg/Gpr88 proteins are highly conserved between human and rodents and show the highest level of homology to receptors for biogenic amines. However, Strg/Gpr88 lacks some residues conserved in all known biogenic amine receptors and hence may represent a novel subtype of GPCR. Northern blot and in situ hybridization analyses revealed that Strg/Gpr88 transcripts are expressed almost exclusively in striatum in both human and rodents. Remarkable conservation in primary structure and a unique expression pattern may indicate a role for Strg/Gpr88 in the fundamental functions of striatum such as the control of motor behavior. (C) 2000 Academic Press.
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