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Ssn6-Tup1 interacts with class I histone deacetylases required for repression
A D Watson1, D G Edmondson, J R Bone
1Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
Genes & Development
|November 9, 2000
Summary
The Ssn6-Tup1 corepressor complex in yeast interacts with histones. Histone hyperacetylation disrupts Ssn6-Tup1 function, suggesting active recruitment of histone deacetylases.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Epigenetics
Background:
- The Ssn6-Tup1 complex is a key transcriptional corepressor in yeast.
- Tup1 directly interacts with histones H3 and H4, and this interaction is crucial for repression.
- Histone acetylation status is known to influence transcriptional regulation.
Purpose of the Study:
- To investigate the role of histone acetylation in Ssn6-Tup1-mediated gene repression.
- To determine if histone deacetylase (HDAC) activity is required for Ssn6-Tup1 function.
- To explore the physical interaction between Ssn6-Tup1 and HDACs.
Main Methods:
- Utilizing yeast genetics to create combined mutations in histone deacetylase genes (RPD3, HOS1, HOS2).
- Assessing Ssn6-Tup1-mediated repression in mutant strains.
- Performing in vitro binding assays to study Tup1-histone interactions.
- Investigating physical interactions between Ssn6-Tup1 components and HDACs.
Main Results:
- Combined mutations in RPD3, HOS1, and HOS2 led to histone hyperacetylation and abolished Ssn6-Tup1 repression.
- This specific combination of mutations caused simultaneous hyperacetylation of both H3 and H4.
- Two class I HDACs were found to physically interact with the Ssn6-Tup1 complex.
Conclusions:
- Histone hyperacetylation disrupts Ssn6-Tup1-mediated repression in yeast.
- Ssn6-Tup1 likely recruits histone deacetylase activity to deacetylate nucleosomes and facilitate Tup1-histone interactions.
- This provides a mechanism for how corepressor function is modulated by epigenetic modifications.
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