ISW1a modulates cohesin distribution in centromeric and pericentromeric regions

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Cohesin complex is essential for holding sister chromatids together during cell division.
• The Scc2-Scc4 complex loads cohesin onto chromatin.
• Regulation of cohesin distribution is crucial for accurate chromosome segregation.

Purpose of the Study:

• To investigate the role of chromatin remodelers in regulating cohesin.
• To identify cohesin binding partners using proteomic screening in yeast.
• To understand how Isw1 chromatin remodeler influences cohesin localization and function.

Main Methods:

• Proteomic screening in budding yeast to identify cohesin interactors.
• Analysis of cohesin accumulation at centromeres and pericentromeres in Isw1 mutants.
• Assessment of chromatin remodeling activity and nucleosomal landscape changes.
• Investigating the interplay between ISW1a, RSC, and cohesin binding.

Main Results:

• Identified Isw1 chromatin remodeler as a cohesin binding partner, interacting with Scc2-Scc4.
• Loss of Isw1 or its activity led to increased cohesin accumulation at centromeres and pericentromeres.
• Isw1 is recruited to centromeres and influences the nucleosomal landscape.
• ISW1a activity, in the absence of RSC, reduces cohesin binding and causes cohesion defects.

Conclusions:

• Chromatin remodelers, specifically ISW1a, play a key role in regulating cohesin distribution on chromosomes.
• Isw1 facilitates cohesin translocation from centromeric loading sites.
• Isw1's function is critical for maintaining proper chromatin organization at centromeres and pericentromeres.
• Interactions between chromatin remodelers and the cohesin machinery are essential for accurate chromosome segregation.