A Multiprotein Mediator of Transcriptional Activation and Its Interaction With the C-terminal Repeat Domain of RNA Polymerase II

Cell. 1994 May 20;77(4):599-608. doi: 10.1016/0092-8674(94)90221-6.

Abstract

A mediator was isolated from yeast that enabled a response to the activator proteins GAL4-VP16 and GCN4 in a transcription system reconstituted with essentially homogeneous basal factors and RNA polymerase II. The mediator comprised some 20 polypeptides, including the three subunits of TFIIF and other polypeptides cross-reactive with antisera against GAL11, SUG1, SRB2, SRB4, SRB5, and SRB6 proteins. Mediator not only enabled activated transcription but also conferred 8-fold greater activity in basal transcription and 12-fold greater efficiency of phosphorylation of RNA polymerase II by the TFIIH-associated C-terminal repeat domain (CTD) kinase, indicative of mediator-CTD interaction. A holoenzyme form of RNA polymerase II was independently isolated that supported a response to activator proteins with purified basal factors. The holoenzyme proved to consist of mediator associated with core 12-subunit RNA polymerase II.

Publication types

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

MeSH terms

  • DNA-Binding Proteins*
  • Fungal Proteins / metabolism
  • Peptides / isolation & purification
  • Peptides / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Kinases / metabolism
  • Protein Structure, Tertiary
  • RNA Polymerase II / chemistry*
  • RNA Polymerase II / isolation & purification
  • RNA Polymerase II / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae Proteins*
  • Trans-Activators / metabolism
  • Transcription Factors / isolation & purification
  • Transcription Factors / metabolism*
  • Transcription, Genetic / physiology
  • Transcriptional Activation / physiology*

Substances

  • DNA-Binding Proteins
  • Fungal Proteins
  • Gal-VP16
  • Peptides
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • Transcription Factors
  • Protein Kinases
  • carboxy-terminal domain kinase
  • RNA Polymerase II