LIGAND-INDEPENDENT REPRESSION BY THE THYROID-HORMONE RECEPTOR-MEDIATED BY A NUCLEAR RECEPTOR CO-REPRESSOR

Thyroid-hormone and retinoic-acid receptors exert their regulatory fun ctions by acting as both activators and repressors of gene expression. A nuclear receptor co-repressor (N-CoR) of relative molecular mass 27 0K has been identified which mediates ligand-independent inhibition of gene transcription by these receptors, suggesting that the molecular mechanisms of repression by thyroid-hormone and retinoic-acid receptor s are analogous to the co-repressor-dependent transcriptional inhibito ry mechanisms of yeast and Drosophila.