Retinoid X receptor-γ gene expression is developmentally regulated in the embryonic rodent peripheral nervous system

Abstract

 The retinoid X receptor-γ (RXRγ) is a transcription factor that belongs to the thyroid hormone/retinoid family of nuclear receptors. Previous studies have shown that RXRγ is expressed in the developing peripheral nervous system (PNS) of chick embryos, but such expression has not been reported previously in rodent embryos. Indeed, the pattern of RXRγ expression appears to be different between avian and rodent species. Using in situ hybridisation and northern blot experiments we show that RXRγ is expressed in elements of the PNS in rat and mouse embryos and in postnatal rats. However, unlike the chick, where RXRγ is expressed from the onset of neural crest migration, rat RXRγ expression in the dorsal root ganglia and trigeminal ganglia was detectable at 14.5 days post coitum (dpc), but not at 13, 12, or 11 dpc. These data suggest that RXRγ may have a role in the dorsal root ganglia and trigeminal ganglia of late embryos, and that this could be evolutionarily conserved between chick and rodent. On the other hand, rat RXRγ transcripts in the facio-acoustic (VII–VIII) ganglion were detectable at 11 dpc in neural crest cells condensing to form this ganglion. We discuss the possible significance of the timing of RXRγ expression in the developing PNS and suggest that closer examination of the structure and function of the PNS of RXRγ null mutant mice would be of interest.