Figure 1

A model for gene regulation by TR. In the absence of T3, TR forms heterodimers with RXR (9-cis retinoic acid receptor) and the heterodimer binds to the T3 response elements (TREs) in the target genes to repress their expression by recruiting corepressor complexes such as those containing the related protein N-CoR or SMRT and HDAC-3. When T3 is present, the corepressor complexes are released upon T3 binding to TR, and coactivator complexes such as those containing SRC, p300, and PRMT1, are recruited. SRC and p300 are histone acetyltransferases and PRMT1 is a histone methyltransferase.