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Enhanced Yeast One-hybrid Screens To Identify Transcription Factor Binding To Human DNA Sequences
Published on: February 11, 2019
Repressive chromatin affects factor binding at yeast HO (homothallic switching) promoter
Shinya Takahata1, Yaxin Yu, David J Stillman
1Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, Utah 84112, USA.
The Journal of Biological Chemistry
|August 16, 2011
Summary
Ash1 protein is crucial for repressing the yeast HO gene by limiting coactivator binding. Its absence allows increased coactivator recruitment and gene expression, revealing Ash1
Area of Science:
- Molecular Biology
- Yeast Genetics
- Chromatin Regulation
Background:
- The yeast HO gene requires multiple activators and coactivators to overcome repressive chromatin.
- Coactivator binding at the HO promoter is interdependent, with the loss of one factor reducing others' recruitment.
- The Rpd3(L) histone deacetylase is recruited to the HO promoter at two distinct cell cycle stages.
Purpose of the Study:
- To investigate the role of Ash1 in regulating HO gene transcription.
- To understand the interplay between Ash1, coactivators, and chromatin structure at the HO promoter.
- To elucidate the mechanism by which Ash1 establishes a repressive environment.
Main Methods:
- Analysis of coactivator binding and recruitment using chromatin immunoprecipitation (ChIP) assays.
- Assessment of gene expression levels under various mutant conditions.
- Investigation of protein-protein interactions and localization within the promoter region.
Main Results:
- Ash1 binds to the URS1 region of the HO promoter.
- An ash1 mutation leads to increased binding of SBF and Rpd3(L) at URS2, suggesting promoter region interaction.
- Loss of Ash1 results in enhanced coactivator recruitment (Swi/Snf, Mediator) and HO expression, even with TFIID pathway defects.
Conclusions:
- Ash1 plays a central role in establishing the repressive chromatin environment at the HO promoter.
- Ash1 limits coactivator binding at URS2 and the TATA region, thereby controlling HO gene transcription.
- The findings highlight a novel mechanism of gene regulation involving long-range interactions mediated by Ash1.
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