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G2-seq: A High Throughput Sequencing-based Technique for Identifying Late Replicating Regions of the Genome
Published on: March 22, 2018
Targeted sister chromatid cohesion by Sir2
Ching-Shyi Wu1, Yu-Fan Chen, Marc R Gartenberg
1Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, United States of America.
Plos Genetics
|February 10, 2011
Summary
Sir2 histone deacetylase is crucial for cohesin binding to silent chromatin in yeast, enabling sister chromatid cohesion. This function is independent of its deacetylase activity, highlighting a unique role for Sir2 in genome stability.
Area of Science:
- * Molecular Biology
- * Genetics
- * Epigenetics
Background:
- * Cohesin is a protein complex essential for sister chromatid cohesion in eukaryotes.
- * In Saccharomyces cerevisiae, cohesin associates with silent chromatin, a heterochromatin-like structure.
- * The mechanism by which cohesin binds silent chromatin remains to be fully elucidated.
Purpose of the Study:
- * To investigate the mechanistic basis for cohesin-mediated cohesion of silent chromatin domains.
- * To identify the specific factors responsible for tethering cohesin to silent chromatin.
- * To differentiate the role of Sir2's deacetylase activity from its role in chromatin cohesion.
Main Methods:
- * Development of a protein-targeting assay in budding yeast (Saccharomyces cerevisiae).
- * Tethering of individual silencing factors to specific genomic sites.
- * Evaluation of sister chromatid pairing using fluorescence microscopy.
Main Results:
- * The Sir2 histone deacetylase (HDAC) was found to be both necessary and sufficient for silent chromatin cohesion.
- * Cohesin genes were required for cohesion, but Sir2's deacetylase activity and other silencing factors were not.
- * A small carboxyl-terminal fragment of Sir2 was sufficient to mediate cohesin binding to silent chromatin.
Conclusions:
- * Sir2 plays a unique, non-enzymatic role in mediating cohesin's association with silent chromatin.
- * This function of Sir2 is distinct from its established histone deacetylase activity.
- * Findings provide novel insights into the regulation of genome stability and chromatin structure.
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Cohesin complexes in Meiotic Division
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Cohesin complexes in Meiotic Division
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02:20Cohesins
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Cohesin complexes in Meiotic Division
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At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
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