Mediator and SAGA Have Distinct Roles in Pol II Preinitiation Complex Assembly and Function

• DOI: 10.1016/j.celrep.2012.10.019
• Publication Date: 2012-11-21T10:15:23Z
• Authors: Xiao-Fen Chen; Lynn Lehmann; Justin J. Lin; Ajay Vashisht; Ryan Schmidt; Roberto Ferrari; Chengyang Huang; Robin McKee; Amber Mosley; Kathrin Plath; Siavash K. Kurdis...; James Wohlschlegel; Michael Carey
• Keywords: Transcription preinitiation complex; RNA polymerase II; Mediator; Transcription

A key feature of RNA polymerase II (Pol II) preinitiation complexes (PICs) is their ability to coordinate transcription initiation with chromatin modification and remodeling. To understand how this coordination achieved, we employed extensive proteomic mechanistic analyses study the composition assembly PICs in HeLa cell mouse embryonic stem (ESC) nuclear extracts. Strikingly, most machinery that necessary for on part PIC. The PIC nearly identical between ESCs cells contains two major coactivator complexes: Mediator SAGA. Genome-wide analysis reveals it has a close correlation Pol II, TATA-binding protein, messenger levels thus may play role assembly. Moreover, coordinates factors into vitro, whereas SAGA acts after allow chromatin.