Action of Retinoids and Retinoic Acids

With current knowledge, the pleiotropic action of retinoic acids and retinoids might be explained mechanistically by the actions of the six known nuclear receptors, the 

Nuclear Receptors as Drug Targets. Edited by Eckhard Ottow and Hilmar Weinmann Copyright 2008 WILEY-VCH Veriag GmbH Co. KGaA, Weinheim ISBN 978-3-527-31872-8 

RAR-RXR heterodimer or RXR-RXR homodimer), the activated receptors bind with high affinity to the specific DNA retinoic acid response element (RARE) and effect mRNA transcription. Ultimately, the retinoid response is mediated by primary target genes, by interference with othertranscription factors or by control of certain posttranscriptional actions. 

These receptors, as heterodimers (RAR-RXR) or homodimers (RXR-RXR), function as RA-inducible transcriptional regulatory proteins by binding to DNA regions called retinoic acid response elements (RAREs) or retinoid X response elements (RXREs) located within the promoter of target genes. RAREs consist of direct repeats of the consensus half-site sequence AGGTCA separated most 

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