Targets of the Gal4 transcription activator in functional transcription complexes

Mol Cell Biol. 2005 Oct;25(20):9092-102. doi: 10.1128/MCB.25.20.9092-9102.2005.


Although biochemical and genetic methods have detected many activator-transcription factor interactions, the direct functional targets of most activators remain undetermined. For this study, photo-cross-linkers positioned within the Gal4 C-terminal acidic activating region were used to identify polypeptides in close physical proximity to Gal4 during transcription activation in vitro. Of six specifically cross-linked polypeptides, three (Tra1, Taf12, and Gal11) are subunits of four complexes (SAGA, Mediator, NuA4, and TFIID) known to play a role in gene regulation. These cross-linking targets had differential effects on activation. SAGA was critical for activation by Gal4, Gal11 contributed modestly to activation, and TFIID and NuA4 were not important for activation under our conditions. Tra1, Taf12, and Gal11 have also been identified as cross-linking targets of the Gcn4 acidic central activating region. Our results demonstrate that two unrelated acidic activators converge on the same set of functional targets.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Basic-Leucine Zipper Transcription Factors
  • Binding Sites / genetics
  • Cross-Linking Reagents
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Molecular Sequence Data
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism*
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*
  • Transcriptional Activation


  • Basic-Leucine Zipper Transcription Factors
  • Cross-Linking Reagents
  • DNA, Fungal
  • DNA-Binding Proteins
  • GAL4 protein, S cerevisiae
  • GCN4 protein, S cerevisiae
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • Transcription Factors