Regional distribution of regulators of G-protein signaling (RGS) 1, 2, 13,14, 16, and GAIP messenger ribonucleic acids by in situ hybridization in rat brain

Regulators of G-protein signaling (RGS) proteins are a novel family of GTPa se-activating proteins that interact with Ga subunits of the Gi/o, Gz, Gq a nd G(12/13) subfamilies to dampen G-protein-coupled receptor (GPCR)-mediate d signaling by accelerating intrinsic G alpha -GTPase activity. In the pres ent study, we report on messenger ribonucleic acid (mRNA) localization in r at brain of six RGS genes by in situ hybridization. The distribution patter ns of RGS2, RGS13, RGS14 and GAIP (Ga interacting protein) overlapped in mo st brain regions examined. Highest regional expression was observed for RGS 2 in the cerebral cortical layers: striatum, hippocampal formation, several thalamic and hypothalamic nuclei and hindbrain regions such as the pontine , interpeduncular and dorsal raphe nuclei. Levels of RGS14 mRNA closely par alleled those of RGS2 expression levels throughout most brain regions. RGS1 3 mRNA was enriched in the hippocampal formation, amygdala, mammillary nucl ei as well as the pontine and interpeduncular nuclei. GAIP expression level s were highest in the hippocampal formation with moderate to low levels pre sent in all other regions studied. Of the six RGS genes probed, RGS 16 mRNA displayed a discrete localization predominantly in the thalamic midline/in tralaminar and principal relay nuclei, and the hypothalamic suprachiasmatic nucleus. RGS1 mRNA signal was not detected in brain. In conclusion, the in situ hybridization studies for RGS2, RGS13, RGS14, RGS16 and GAIP mRNAs ex tend our knowledge of the distribution of RGS genes expressed in the rat ce ntral nervous system, and indicate overlapping RGS-enriched regions that ma y be indicative of functional diversification in GPCR signaling pathway mod ulation. (C) 2001 Elsevier Science B.V. All rights reserved.