Transcript Analytical and Chromatography - Sigma

Transcription Activation by Nuclear Receptors
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Transcription Activation by Nuclear Receptors
• Retinoid X receptor (RXR) and Retinoic Acid receptor (RAR) are nuclear
receptors that bind either all trans-retinoic (tRA) or 9-cis-retinoic acid (9cis-RA). In the absence of ligand, corepressors, such as Nuclear
Receptor Corepressor (NCoR), Silencing Mediator of Retinoid and
Thyroid Hormone Receptor (SMRT), and Histone Deacetylase-1 (HDAC1) associate with the RAR:RXR heterodimer complex and repress
transcription. The histone deacetylase activity of the complex helps
maintain tight association between the deacetylated histones and
chromatin that results in this repression.
sigma-aldrich.com/cellsignaling
Transcription Activation by Nuclear Receptors
sigma-aldrich.com/cellsignaling
Transcription Activation by Nuclear Receptors
• When tRA or 9-cis-RA binds to the RAR:RXR complex, a conformational
change in the receptors causes the dissociation of the corepressors and
subsequent recruitment and binding of coactivators such as Steroid
Receptor Coactivator-1 (SRC-1), Glucocorticoid Receptor Interacting
Protein-1 (GRIP-1), CREB Binding Protein (CBP) and CBP-Associated
Factor (PCAF). This receptor:coactivator complex activates histone
acetyltransferase (HAT). Acetylated histones dissociate from the
chromatin and allow for the basal transcription machinery complex to
bind to DNA and activate transcription of target genes.
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