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Micronutrient Information Center

A simplified model of the regulation of gene expression by retinoic acid (RA) isomers


All-trans-RA and 9-cis-RA are transported to the nucleus of the cell bound to cytoplasmic retinoic acid-binding proteins. Within the nucleus, all-trans-RA binds to retinoic acid receptors (RAR) and 9-cis-RA binds to retinoid receptors (RXR). RAR and RXR form RAR/RXR heterodimers, which bind to regulatory regions of the chromosome called retinoic acid response elements (RARE). Binding of all-trans-RA and 9-cis-RA to RAR and RXR respectively allows the complex to regulate the rate of gene transcription.