Transcriptional activation by Gcn4p involves independent interactions with the SWI/SNF complex and the SRB/mediator

Mol Cell. 1999 Oct;4(4):657-64. doi: 10.1016/s1097-2765(00)80217-8.


Mutations in three subunits of the SWI/SNF complex and in the Med2p subunit of the SRB/mediator of pol II holoenzyme impaired Gcn4p-activated transcription of HIS3 without reducing Gcn4p-independent transcription of this gene. Recombinant Gcn4p interacted with SWI/SNF and SRB/mediator subunits in cell extracts in a manner dependent on the same hydrophobic clusters in the Gcn4p activation domain; however, higher concentrations of Gcn4p were required for binding to SWI/SNF versus SRB/mediator subunits. In addition, SRB/mediator and SWI/SNF subunits did not coimmunopreciptate from the extracts. These findings, together with the fact that Gcn4p specifically interacted with purified SWI/SNF, strongly suggest that Gcn4p independently recruits SWI/SNF and holoenzyme to its target promoters in the course of activating transcription.

Publication types

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

MeSH terms

  • DNA Polymerase II / genetics*
  • DNA-Binding Proteins / metabolism*
  • Fungal Proteins / metabolism*
  • Gene Expression Regulation, Fungal
  • Hydro-Lyases / genetics
  • Mediator Complex
  • Mutation
  • Nuclear Proteins*
  • Nucleosomes / metabolism*
  • Protein Binding
  • Protein Kinases / metabolism*
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins*
  • Transcription Factors / metabolism*
  • Transcriptional Activation*
  • Yeasts / metabolism


  • DNA-Binding Proteins
  • Fungal Proteins
  • Mediator Complex
  • Nuclear Proteins
  • Nucleosomes
  • Recombinant Proteins
  • SAGA protein, Emericella nidulans
  • SRB2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Protein Kinases
  • DNA Polymerase II
  • Hydro-Lyases
  • imidazoleglycerolphosphate dehydratase