The mediator of RNA polymerase II

Chromosoma. 2005 Mar;113(8):399-408. doi: 10.1007/s00412-005-0329-5. Epub 2005 Feb 3.


Mediator (TRAP/ARC/PC2) is a large (22-28 subunit) protein complex that binds RNA polymerase II and controls transcription from class II genes. The evolutionarily conserved core of Mediator is found in all eukaryotes. It binds RNA polymerase II and is probably critical for basal transcription but it also mediates activation and repression of transcription. During evolution the complex has acquired additional species-specific subunits. These serve as an interface for regulatory factors and support specific signalling pathways. Recent mechanistic studies are consistent with the hypothesis that Mediator marks genes for binding by RNA polymerase II whereupon it subsequently activates the preinitiation complex. It is further likely that Mediator coordinates the recruitment of chromatin-modifying cofactor activities.

Publication types

  • Review

MeSH terms

  • Animals
  • Biological Evolution
  • Cell Nucleus / metabolism
  • Chromatin / metabolism
  • Humans
  • Mediator Complex
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism*
  • Protein Conformation
  • RNA Polymerase II / biosynthesis*
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism*
  • Transcription Factors / physiology


  • Chromatin
  • DRIP, VDR interacting protein complex
  • Mediator Complex
  • Nuclear Proteins
  • Trans-Activators
  • Transcription Factors
  • RNA Polymerase II