TRANSCRIPTION FACTOR-SPECIFIC REQUIREMENTS FOR COACTIVATORS AND THEIRACETYLTRANSFERASE FUNCTIONS

Different classes of mammalian transcription factors-nuclear receptors , cyclic adenosine 3',5'-monophosphate-regulated enhancer binding prot ein (CREB), and signal transducer and activator of transcription-1 (ST AT-1)-functionally require distinct com ponents of the coactivator com plex, including CREB-binding protein (CBP/p300), nuclear receptor coac tivators (NCoAs), and p300/CBP-associated factor (p/CAF), based on the ir platform or assembly properties. Retinoic acid receptor, CREB, and STAT-1 also require different histone acetyltransferase (HAT) activiti es to activate transcription. Thus, transcription factor-specific diff erences in configuration and content of the coactivator complex dictat e requirements for specific acetyltransferase activities, providing an explanation, at least in part, for the presence of multiple HAT compo nents of the complex.