NAT, a human complex containing Srb polypeptides that functions as a negative regulator of activated transcription

Mol Cell. 1998 Aug;2(2):213-22. doi: 10.1016/s1097-2765(00)80131-8.


A complex that represses activated transcription and contains the human homologs of the yeast Srb7, Srb10, Srb11, Rgr1, and Med6 proteins was isolated. The complex is devoid of the Srb polypeptides previously shown to be components of the yeast Mediator complex that functions in transcriptional activation. The complex phosphorylates the CTD of RNA polymerase II (RNAPII) at residues other than those phosphorylated by the kinase of TFIIH. Moreover, the complex specifically interacts with RNAPII. The interaction is not mediated by the CTD of RNAPII, but is precluded by phosphorylation of the CTD. Our results indicate that the complex is a subcomplex of the human RNAPII holoenzyme. We suggest that the RNAPII holoenzyme is a transcriptional control panel, integrating and responding to specific signals to activate or repress transcription.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cyclin-Dependent Kinases*
  • Cyclins
  • DNA, Complementary / genetics
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Humans
  • Macromolecular Substances
  • Mediator Complex
  • Molecular Sequence Data
  • Phosphorylation
  • RNA Polymerase II / metabolism
  • Repressor Proteins / chemistry
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Amino Acid
  • Trans-Activators*
  • Transcription Factors / chemistry
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*
  • Transcriptional Activation*


  • Cyclins
  • DNA, Complementary
  • Fungal Proteins
  • MED21 protein, human
  • MED6 protein, human
  • Macromolecular Substances
  • Mediator Complex
  • RGR1 protein, S cerevisiae
  • Repressor Proteins
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • Transcription Factors
  • SSN8 protein, S cerevisiae
  • Cyclin-Dependent Kinases
  • RNA Polymerase II

Associated data

  • GENBANK/AF074723