Brain-specific expression of novel G-protein-coupled receptors, with homologies to Xenopus PSP24 and human GPR45

From mouse genomic libraries and human brain cDNA, we cloned three novel G- protein-coupled receptors (GPCRs), which have about 55-70% homologies with Xenopus PSP24 (xPSP24). Together with another human cDNA (GPR45) cloned by Marchese ed al. (Genomics 56, 12-21, 1999). they comprise a family of mamma lian PSP24s. Therefore, we termed these clones mouse PSP24 alpha, beta, and human PSP24 alpha, beta. The homologies between alpha and beta isoforms we re 54% for human and 51% for mouse clones. None of these clones shares sequ ence similarities with any known mammalian GPCRs, thus forming a unique gen e family. Northern blot demonstrated that both of the mouse transcripts wer e predominantly expressed in the brain. In situ hybridization of brain sect ions showed that the expression was observed in neuronal cells, such as olf actory mitral cells, cortical neurons, hippocampal pyramidal cells, and Pur kinje cells in the cerebellum. We suggest that mammalian PSP24 is a distinc t GPCR family and plays a role in the brain function. (C) 2000 Academic Pre ss.