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Updated: May 26, 2026
05:35
Immunofluorescence Analysis of Endogenous and Exogenous Centromere-kinetochore Proteins
Published on: March 3, 2016
Determinants of centromeric nucleosome conformation.
Emeleeta A Paintsil1, Joshua Lee2, Sarah S Meidl Zahorodny1
1Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States.
Biorxiv : the Preprint Server for Biology
|May 25, 2026
Summary
Centromeric chromatin uses CENP-A nucleosomes, which are more open than canonical H3 nucleosomes. Multiple histone regions cooperate to stabilize DNA, controlling nucleosome conformation.
Area of Science:
- Epigenetics and Chromatin Biology
- Molecular and Structural Biology
Background:
- Centromeric chromatin is characterized by CENP-A nucleosomes, essential for kinetochore assembly.
- CENP-A nucleosomes exhibit a more open DNA conformation compared to canonical H3 nucleosomes.
- The role of CENP-A's intrinsically disordered N-terminal regions in nucleosome conformation was previously unknown.
Purpose of the Study:
- To investigate the contribution of CENP-A's N-terminal tail, latch, and αN-helix regions to nucleosome conformation.
- To determine how these regions influence DNA accessibility and nucleosome unwrapping.
- To compare the conformational roles of CENP-A and canonical H3 histone N-terminal regions.
Main Methods:
- Utilized Micrococcal Nuclease (MNase) digestion assays.
- Employed coarse-grained molecular dynamics simulations.
- Studied H3/CENP-A chimera histone nucleosomes with targeted region swaps.
Main Results:
- Removal or substitution of H3 N-terminal regions with CENP-A counterparts increased DNA accessibility and unwrapping.
- Any single CENP-A N-terminal region was sufficient to open canonical nucleosome DNA.
- Multiple H3 N-terminal regions acted cooperatively to stabilize DNA, with progressive incorporation yielding closed conformations.
Conclusions:
- Concerted interactions across multiple N-terminal regions stabilize canonical nucleosome DNA.
- The flexibility of centromeric nucleosomes arises from multi-region redundancy.
- Nucleosome conformation is finely tuned by coordinated histone-DNA interactions.
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