Murine isoforms of retinoic acid receptor gamma with specific patterns of expression.

We have characterized seven murine retinoic acid receptor gamma cDNA isoforms (mRAR-gamma 1 to -gamma 7) generated by alternative splicing of at least seven exons. These isoforms differ from one another in their 5' untranslated region and in two cases (mRAR-gamma 1 and -gamma 2) differ in their N-terminal A region, which is known to be important for differential transactivation by other nuclear receptors. mRAR-gamma 1 and -gamma 2, the predominant isoforms, are differentially expressed in adult tissues and during embryogenesis. Most notably, skin contains almost exclusively mRAR-gamma 1 transcripts. The conservation of the RAR-gamma isoforms from mouse to human together with their patterns of expression suggests that they perform specific functions, which may account for the pleiotropic effect of retinoic acid in embryogenesis and development.