Transcriptional regulation and the role of diverse coactivators in animal cells

Transcriptional regulation in eukaryotes involves structurally and functionally distinct nuclear RNA polymerases, corresponding general initiation factors, gene-specific (DNA-binding) regulatory factors, and a variety of coregulatory factors that act either through chromatin modifications (e.g. histone acetyltransferases and methyltransferases) or more directly (e.g. Mediator) to facilitate formation and function of the preinitiation complex. Biochemical studies with purified factors and DNA versus recombinant chromatin templates have provided insights into the nature and mechanism of action of these factors, including pathways for their sequential function in chromatin remodeling and preinitiation complex formation/function (transcription) steps and a possible role in facilitating the transition between these steps.