Related Experiment Video
Updated: Jun 22, 2025
09:52
Probing The Structure And Dynamics Of Nucleosomes Using Atomic Force Microscopy Imaging
Published on: January 31, 2019
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Nanoscale Structure, Interactions, and Dynamics of Centromere Nucleosomes
Shaun Filliaux1, Zhiqiang Sun1, Yuri L Lyubchenko1
1Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6025, United States.
Biomacromolecules
|July 3, 2024
Summary
Centromere nucleosomes, including canonical H3 and variant CENP-A, show DNA unwrapping via AFM. CENP-A nucleosomes exhibit greater stability than H3 nucleosomes, revealing distinct dynamics.
Area of Science:
- Molecular Biology
- Chromatin Structure
- Biophysics
Background:
- Centromeres are crucial chromosomal regions for cell division.
- They contain canonical nucleosomes (H3-H4) and CENP-A nucleosomes (CENP-A replacing H3).
- CENP-A nucleosomes exhibit altered DNA wrapping (121 bp vs. 147 bp).
Purpose of the Study:
- To investigate the nanoscale features and dynamics of canonical and CENP-A nucleosomes.
- To compare the stability and DNA unwrapping mechanisms of these two nucleosome types.
Main Methods:
- Atomic Force Microscopy (AFM)
- High-speed AFM (HS-AFM) for nanoscale characterization and dynamic observation.
Main Results:
- Both nucleosome types display spontaneous, asymmetric DNA unwrapping via a transient state (~100 bp).
- HS-AFM reveals CENP-A nucleosomes are more stable than H3 nucleosomes.
- Histone core dissociation precedes nucleosome dissociation in H3 nucleosomes.
Conclusions:
- Distinct DNA unwrapping and stability profiles exist between CENP-A and H3 nucleosomes.
- These findings offer insights into the functional differences and biological roles of CENP-A nucleosomes in centromere function.
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