Figure 4.

Model for gene activation by TR. The multistep model is based on past and present studies showing ligand-independent TR-mediated repression through TR-interacting corepressors (SMRT/N-COR, SIN3) and the associated histone deacetylase (HDAC), ligand-dependent dissociation of corepressors and corresponding association of coactivators (CBP/p300, SRC-1-related factors, and PCAF) with HAT activity, and ligand-dependent association of TRAPs that act in conjunction with general coactivators PC2 and PC4 to mediate transcription from DNA templates by RNA polymerase II and general initiation factors. For further details and references see Discussion.