Mouse G-protein gamma3 expression in the developing CNS and neural crest cell derivatives

Heterotrimeric G-protein signaling, involving alpha, beta and gamma subunits, plays a number of roles in differentiation and development. Individual gamma subunits interact with a beta subunit and as a heterodimer, is responsible for modulating many G protein-mediated cellular responses. The 12 gamma subunits in mammals have highly variable distribution and expression patterns in adult tissues. gamma3 is abundantly and widely expressed in the brain and when its expression is knocked-out, the mice show increased susceptibility to seizures, reduced body weights and decreased adiposity compared to the wild-type littermates (Schwindinger et al., 2004). Recent evidence has shown the Gng3 gene being strongly induced in activated CD4+ T-cells (Dubeykovskiy et al., 2006) and its involvement in the developing mammalian enteric nervous system (Heanue and Pachnis, 2006). Given this diversity in expression and interest in finding models of human disease, and to extend our previous investigation with zebrafish gamma3 (Kelly et al., 2001), we undertook an analysis to report the temporal and spatial expression patterns of gamma3 mRNA during mouse embryogenesis. Analysis reveals that gamma3 transcripts were first expressed in mid-late embryonic stages. Specifically, signals were predominant in the CNS and in neural crest cell derivatives including but not limited to the trigeminal and dorsal root (spinal) ganglia, and in cells of the adrenal medulla. These data indicate that G protein coupled signaling involving gamma3 participates in a number of physiological roles, not only in the CNS, but also in numerous cells derived from the neural crest.