Cti6, a PHD domain protein, bridges the Cyc8-Tup1 corepressor and the SAGA coactivator to overcome repression at GAL1.
The yeast Cyc8 and Tup1 proteins form a corepressor complex that, when tethered to DNA, turns off transcription. Release of the Cyc8-Tup1 corepressor from a promoter has been considered as a prerequisite for subsequent transcriptional activation. Contrasting this, we demonstrate that Cyc8-Tup1 is continuously associated with target promoters under both ... repressive and inducing conditions. At the GAL1 promoter, Cyc8-Tup1 facilitates recruitment of SAGA (Spt-Ada-Gcn5-acetyltranferase) via Cti6, a PHD domain protein that physically links the Cyc8-Tup1 and SAGA complexes. Lack of functional corepressor renders GAL1 transcription largely independent of specific SAGA subunits. Thus, corepressor's release is not the mechanism of derepression; instead, it is the coactivator complex that alleviates Cyc8-Tup1-mediated repression under induction conditions.
Mesh Terms:
DNA-Binding Proteins, Fungal Proteins, Gene Expression Regulation, Fungal, Macromolecular Substances, Nuclear Proteins, Promoter Regions, Genetic, Protein Structure, Tertiary, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors, Transcription, Genetic
DNA-Binding Proteins, Fungal Proteins, Gene Expression Regulation, Fungal, Macromolecular Substances, Nuclear Proteins, Promoter Regions, Genetic, Protein Structure, Tertiary, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors, Transcription, Genetic
Mol. Cell
Date: Jun. 01, 2002
PubMed ID: 12086626
View in: Pubmed Google Scholar
Download Curated Data For This Publication
16198
Switch View:
- Interactions 7