Head Module Control of Mediator Interactions

Yuichiro Takagi, Guillermo Calero, Hirofumi Komori, Jesse A. Brown, Andreas H. Ehrensberger, Andy Hudmon, Francisco Asturias, Roger D. Kornberg

Research output: Contribution to journalArticle

94 Scopus citations


Yeast Mediator proteins interacting with Med17(Srb4) have been expressed at a high level with the use of recombinant baculoviruses and recovered in homogeneous form as a seven subunit, 223 kDa complex. Electron microscopy and single-particle analysis identify this complex as the Mediator head module. The recombinant head module complements "headless" Mediator for the initiation of transcription in vitro. The module interacts with an RNA polymerase II-TFIIF complex, but not with the polymerase or TFIIF alone. This interaction is lost in the presence of a DNA template and associated RNA transcript, recapitulating the release of Mediator that occurs upon the initiation of transcription. Disruption of the head module in a temperature-sensitive mutant in vivo leads to the release of middle and tail modules from a transcriptionally active promoter. The head module evidently controls Mediator-RNA polymerase II and Mediator-promoter interactions.

Original languageEnglish (US)
Pages (from-to)355-364
Number of pages10
JournalMolecular Cell
Issue number3
StatePublished - Aug 4 2006



  • DNA

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

Cite this

Takagi, Y., Calero, G., Komori, H., Brown, J. A., Ehrensberger, A. H., Hudmon, A., Asturias, F., & Kornberg, R. D. (2006). Head Module Control of Mediator Interactions. Molecular Cell, 23(3), 355-364. https://doi.org/10.1016/j.molcel.2006.06.007