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Nuclear Actin Polymerized by mDia2 Confines Centromere Movement during CENP-A Loading
Chenshu Liu1, Ruijun Zhu1, Yinghui Mao1
1Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, 630 W 168(th) Street, New York, NY 10032, USA.
Iscience
|November 19, 2018
Summary
Diaphanous formin mDia2 and nuclear actin filaments are crucial for maintaining centromere identity by ensuring stable incorporation of centromere protein A (CENP-A). This process involves confining centromere movement during CENP-A loading.
Area of Science:
- Cell Biology
- Epigenetics
- Chromatin Biology
Background:
- Centromeres are epigenetic marks on chromosomes, defined by CENP-A.
- Stable CENP-A incorporation into centromeric chromatin is vital for cell division but poorly understood.
Purpose of the Study:
- To investigate the mechanism of stable CENP-A incorporation into centromeric chromatin.
- To identify factors regulating CENP-A replenishment and centromere identity maintenance.
Main Methods:
- Investigated the role of diaphanous formin mDia2 in CENP-A loading.
- Utilized techniques to study nuclear actin dynamics and centromere movement.
- Examined the impact of depleting nuclear actin or MgcRacGAP on CENP-A loading chaperones.
Main Results:
- Discovered mDia2 is essential for stable CENP-A incorporation.
- Showed mDia2-mediated nuclear actin filaments in G1 are required for CENP-A maintenance.
- Found mDia2 and nuclear actin constrain centromere movement during CENP-A loading.
- Observed depletion of nuclear actin or MgcRacGAP prolongs HJURP association with centromeres.
Conclusions:
- Nuclear actin polymerized by mDia2 physically confines G1 centromeres.
- This confinement facilitates productive HJURP-mediated CENP-A loading.
- The mDia2-actin pathway is critical for stable centromere epigenetic identity maintenance.
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