Inhibition of TATA-Binding Protein Function by SAGA Subunits Spt3 and Spt8 at Gcn4-Activated Promoters

• DOI: 10.1128/mcb.20.2.634-647.2000
• Publication Date: 2002-07-27T10:03:53Z
• Authors: Rimma Belotserkov...; David E. Sterner; Min Deng; Michael H. Sayre; Paul M. Lieberman; Shelley L. Berger
• Keywords: Derepression; Transcription

SAGA is a 1.8-MDa yeast protein complex that composed of several distinct classes transcription-related factors, including the adaptor/acetyltransferase Gcn5, Spt proteins, and subset TBP-associated factors. Our results indicate mutations completely disrupt (deletions SPT7 orSPT20) strongly reduce transcriptional activation at theHIS3 TRP3 genes Gcn5 required for normal HIS3 start site selection. Surprisingly, in proteins involved SAGA-TBP interaction (Spt3 Spt8) cause derepression andTRP3 transcription uninduced state. Consistent with this finding, wild-type inhibits TBP binding to promoter vitro, while lacking Spt3 or Spt8 not inhibitory. We detected two forms cell extracts and, strikingly, one lacks Spt8. Conditions induceHIS3 result an altered balance between these complexes favor form without These suggest composition may be dynamic vivo regulated through dissociable inhibitory subunits.