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Global alterations in chromatin accessibility associated with loss of SIN4 function
T Macatee1, Y W Jiang, D J Stillman
1Department of Biochemistry and Molecular Biology, University of Texas M.D.Anderson Cancer Center, Houston, TX 77030, USA.
Nucleic Acids Research
|March 15, 1997
Summary
The Sin4 protein (Sin4p) regulates gene expression by influencing chromatin structure. Loss of Sin4 increases chromatin accessibility, impacting gene regulation in yeast.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Chromatin Biology
Background:
- Sin4p is a mediator complex component linked to RNA polymerase II.
- Sin4 is crucial for regulating various yeast genes, including HO endonuclease and cell-specific genes.
- Previous research suggests Sin4 influences transcription via chromatin organization.
Purpose of the Study:
- To investigate if Sin4 is essential for nucleosome positioning.
- To analyze the chromatin structure related to MATa cell-specific repression in sin4 MATalpha cells.
Main Methods:
- Analysis of nucleosome positioning in sin4 mutant yeast cells.
- Micrococcal nuclease digestion assay to assess chromatin sensitivity.
- Examination of histone gene expression and modification levels.
Main Results:
- Loss of Sin4 did not affect nucleosome location.
- Chromatin from sin4 cells showed significantly increased sensitivity to micrococcal nuclease digestion.
- This hypersensitivity was independent of histone gene expression or modification changes.
Conclusions:
- Sin4 directly or indirectly regulates global chromatin accessibility in yeast.
- Findings provide a molecular basis for observed similarities between sin4 and histone mutations.
- Sin4 plays a role in maintaining proper chromatin structure for gene regulation.