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Updated: May 22, 2026

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Interaction of the mediator head module with RNA polymerase II
Gang Cai1, Yuriy L Chaban, Tsuyoshi Imasaki
1Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Abstract:
Mediator, a large (21 polypeptides, MW ∼1 MDa) complex conserved throughout eukaryotes, plays an essential role in control of gene expression by conveying regulatory signals that influence the activity of the preinitiation complex. However, the precise mode of interaction between Mediator and RNA polymerase II (RNAPII), and the mechanism of regulation by Mediator remain elusive. We used cryo-electron microscopy and reconstituted in vitro transcription assays to characterize a transcriptionally-active complex including the Mediator Head module and components of a minimum preinitiation complex (RNAPII, TFIIF, TFIIB, TBP, and promoter DNA). Our results reveal how the Head interacts with RNAPII, affecting its conformation and function.
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