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Updated: May 14, 2026
05:35
Immunofluorescence Analysis of Endogenous and Exogenous Centromere-kinetochore Proteins
Published on: March 3, 2016
γH2A-binding protein Brc1 affects centromere function in fission yeast.
Si Young Lee1, Sophie Rozenzhak, Paul Russell
1Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.
Molecular and Cellular Biology
|January 30, 2013
Summary
Brc1 protein stabilizes stalled replication forks in fission yeast, which is crucial for maintaining pericentromeric heterochromatin and ensuring accurate chromosome segregation during cell division.
Area of Science:
- Cell Biology
- Genetics
- Epigenetics
Background:
- Pericentromeric heterochromatin is vital for centromere function and is transmitted via RNA interference (RNAi).
- Histone H2A phosphorylation (γH2A) recruits Brc1 to pericentromeric heterochromatin during S phase.
- Brc1's role in centromere function, beyond stabilizing replication forks, was previously unknown.
Purpose of the Study:
- To investigate the role of Brc1 in pericentromeric heterochromatin maintenance and centromere function.
- To determine if Brc1's replication fork stabilization activity influences centromere integrity.
- To elucidate the interplay between Brc1, γH2A, and chromosome segregation.
Main Methods:
- Localization studies of Brc1 in fission yeast pericentromeric heterochromatin.
- Assays for histone modifications (H3K9me2) and gene silencing.
- Sensitivity tests to microtubule-destabilizing agents (thiabendazole).
- Analysis of chromosome missegregation.
- Genetic manipulation of histone H2A phosphorylation sites.
Main Results:
- Brc1 localizes to pericentromeric heterochromatin during S phase and enhances H3K9me2 and gene silencing.
- Loss of Brc1 leads to increased sensitivity to thiabendazole and chromosome missegregation.
- Brc1 retains function independently of γH2A binding.
- Eliminating histone H2A serine-121 sensitizes cells lacking γH2A or Brc1 to replication stress.
Conclusions:
- Brc1-mediated stabilization of stalled replication forks is essential for efficient pericentromeric heterochromatin transmission.
- Accurate transmission of pericentromeric heterochromatin is required for proper chromosome segregation during mitosis.
- Brc1 plays a critical role in linking replication fork stability to centromere function and genomic stability.
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