A conserved mRNA expression profile of SREB2 (GPR85) in adult human, monkey, and rat forebrain.

SREB is a subfamily of G-protein-coupled receptors, which consists of SREB1 (GPR27), SREB2 (GPR85), and SREB3 (GPR173). Its high evolutionary conservation and predominant expression in the CNS suggest that SREB family members and their undiscovered ligand(s) may have significant functions in the nervous system. SREB2 is the most conserved receptor throughout vertebrate evolution. As a first step in understanding the function of the SREB family, we have determined the anatomical gene expression profile of SREB2 in adult human, monkey, and rat forebrain using in situ hybridization histochemistry. The expression pattern of SREB2 mRNA was well conserved across three mammalian species. SREB2 mRNA was expressed in neurons throughout the brain and the most abundant expression was detected in the hippocampal dentate gyrus in all species examined. The areas expressing high levels of SREB2 mRNA overlap with brain structures known to possess high levels of plasticity, namely, the hippocampal formation, olfactory system, and supraoptic and paraventricular nuclei. Further, the anatomical expression of SREB1 and SREB3 overlapped with that of SREB2 in the adult monkey brain. Together, these data suggest a possible link between SREB family and neural plasticity, which may explain its extremely high conservation throughout vertebrate evolution.