RNA polymerase II holoenzyme contains SWI/SNF regulators involved in chromatin remodeling.

The RNA polymerase II holoenzyme contains RNA polymerase II, a subset of general transcription factors and SRB regulatory proteins. We report here that SWI and SNF gene products, previously identified as global gene regulators whose functions include remodeling chromatin, are also integral components of the yeast RNA polymerase II holoenzyme. The SWI/SNF proteins are components of the SRB complex, also known as the mediator, which is tightly associated with the RNA polymerase II C-terminal repeat domain. The SWI/SNF components provide the holoenzyme with the capacity to disrupt nucleosomal DNA and thus facilitate stable binding of various components of the transcription initiation complex at promoters.