The Spt components of SAGA facilitate TBP binding to a promoter at a post-activator-binding step in vivo
Abstract
The SAGA complex of Saccharomyces cerevisiae is required for the transcription of many RNA polymerase II-dependent genes. Previous studies have demonstrated that SAGA possesses histone acetyltransferase activity, catalyzed by the SAGA component Gcn5. However, the transcription of many genes, although SAGA dependent, is Gcn5 independent, suggesting the existence of distinct SAGA activities. We have studied the in vivo role of two other SAGA components, Spt3 and Spt20, at the well-characterized GAL1 promoter. Our results demonstrate that both Spt3 and Spt20 are required for the binding of TATA-binding protein but not of the activator Gal4 and that this role is Gcn5 independent. These results suggest a coactivator role for Spt3 and Spt20 in the recruitment of TBP.
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Footnotes
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↵Present address: Unité de Génétique Moléculaire Murine, Unité de Recherche Associeé–Centre National de la Recherche Scientifique (URA–CNRS) 1968, Institute Pasteur, 75724 Paris Cedex 15, France.
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↵Corresponding author.
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E-MAIL Winston{at}rascal.med.Harvard.edu; FAX (617) 432-3993.
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- Received September 8, 1999.
- Accepted September 28, 1999.
- Cold Spring Harbor Laboratory Press
