The early expression of Rev-erbbeta occurs in the developing nervous system of mouse embryo

The orphan ligand nuclear receptor Rev-erbbeta acts in vitro as a negative regulator of transcription. However, its precise physiological role is still unknown. As a first attempt to better understand its biological function, we have studied the distribution and the localization of the Rev-erbbeta mRNA transcripts in different mouse embryonal carcinoma cell lines, in mouse embryos and adult tissues. Our results indicated that Rev-erbbeta transcripts are present in both the non-differentiated and differentiated F9 cells into either parietal or visceral endoderm. At 12.5 days of gestation (E12.5) of mouse embryos, Rev-erbbeta transcripts were localized only in the developing nervous system. In contrast, at later stages of development as well as in the adult, its messengers were widely distributed. These results suggest that Rev-erbbeta may have different roles at the different stages of mouse development, with a more specific role in the nervous system at earlier stages.