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Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A
Published on: June 10, 2020
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Ccp1 Homodimer Mediates Chromatin Integrity by Antagonizing CENP-A Loading
Qianhua Dong1, Feng-Xiang Yin2, Feng Gao3
1Department of Biology, New York University, New York, NY 10003, USA.
Molecular Cell
|September 27, 2016
Summary
Researchers discovered Ccp1, a protein that regulates CENP-A levels at centromeres. Ccp1 prevents incorrect CENP-A loading and helps maintain centromere identity, ensuring proper chromosome segregation.
Area of Science:
- Epigenetics and Chromosome Biology
- Molecular Cell Biology
Background:
- Centromere specification relies on CENP-A, a histone H3 variant replacing canonical H3.
- Mechanisms maintaining the CENP-A/H3 ratio and excluding CENP-A from non-centromeric regions are largely unknown.
Purpose of the Study:
- To investigate the regulation of CENP-A loading and homeostasis at centromeres.
- To identify factors involved in preventing ectopic CENP-A assembly.
Main Methods:
- Identified and characterized Ccp1, a novel NAP family protein in fission yeast.
- Investigated Ccp1's interaction with CENP-A and its recruitment to centromeres.
- Analyzed Ccp1's role in CENP-A eviction with H2A.Z.
- Performed structural analyses of Ccp1.
Main Results:
- Ccp1 antagonizes CENP-A loading at both centromeric and non-centromeric chromatin.
- Ccp1 is recruited to centromeres post-mitosis, similar to the CENP-A loading factor HJURP.
- Ccp1 collaborates with H2A.Z to remove ectopic CENP-A from euchromatin.
- Ccp1 functions as a homodimer to inhibit CENP-A loading.
Conclusions:
- Ccp1 plays a critical role in maintaining CENP-A homeostasis at centromeres.
- Ccp1 actively prevents the assembly of CENP-A in non-centromeric regions, safeguarding genome stability.
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