Ligand-independent repression by the thyroid hormone receptor mediated by a nuclear receptor co-repressor

Thyroid-hormone and retinoic-acid receptors, attached to the retinoid-X receptor as heterodimers to cognate DNA positions, mediate ligand-independent transcriptional repression by effecting both positive and negative gene expression when their ligands are present or absent. A 270 K protein, named the nuclear receptor co-repressor, mediates ligand-independent transcriptional repression similar to the processes in yeast and Drosophila.