Retinoic acid (RA), the major bioactive metabolite of retinol or vitamin A, induces a spectrum
of pleiotropic effects in cell growth and differentiation that are relevant for embryonic
development and adult physiology. The RA activity is mediated primarily by members of the
retinoic acid receptor (RAR) subfamily, namely RARα, RARβ and RARγ, which belong to the
nuclear receptor (NR) superfamily of transcription factors. RARs form heterodimers with
members of the retinoid X receptor (RXR) subfamily and act as ligand-regulated …