 RAR-gamma-RXRalpha Degradation In response to Retinoic Acid (a metabolite of Vitamin-A (all-trans-Retinol), which affects gene transcription), target genes are regulated by two families of nuclear receptors, the RARs (Retinoic Acid Receptors) and the RXRs (Retinoid X Receptors) that bind as RAR/RXR heterodimers to response elements located in their promoters. The all-trans-Retinoic Acid, the Carboxylic Acid form of Vitamin-A is of biological significance since it is predominant under most physiological situations and explains all of the biological effects of Vitamin-A (Ref.1). Biologically active ligands for the RARs include all-trans-Retinoic Acid, 9-cis-Retinoic Acid among others, yet circulating levels of 9-cis-Retinoic Acid are much lower than those of all-trans-Retinoic Acid and the physiological significance of .... more | |