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Author Spotlight: Efficient Nucleosome Reconstitution for Single-Molecule Techniques
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PICH acts as a force-dependent nucleosome remodeler.
Dian Spakman1, Tinka V M Clement1, Andreas S Biebricher1
1Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
Nature Communications
|November 26, 2022
Summary
The protein PICH ( anaphase DNA repair factor) remodels nucleosomes under tension, resolving DNA entanglements in chromatin bridges to prevent genome instability. This study provides direct evidence of its mechanism.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Unresolved DNA entanglements in anaphase can form chromatin bridges, leading to genome instability.
- The SNF2 protein PICH (PICHeads) is hypothesized to resolve these bridges by remodeling nucleosomes, but direct evidence is lacking.
Purpose of the Study:
- To provide direct in vitro evidence of nucleosome remodeling by PICH in a tension-mimicking assay.
- To elucidate the molecular mechanism by which PICH resolves chromatin bridges.
Main Methods:
- Development of an in vitro single-molecule assay using dual-trap optical tweezers.
- Observation of PICH and histone interactions with a nucleosome-array construct under tension using fluorescence imaging.
Main Results:
- PICH acts as a tension- and ATP-dependent nucleosome remodeler.
- PICH facilitates nucleosome unwrapping and subsequent sliding of histones along DNA.
- Demonstrated PICH's direct role in chromatin bridge dissolution.
Conclusions:
- This study provides the first direct evidence of PICH's nucleosome remodeling activity.
- PICH plays a crucial role in resolving chromatin bridges during anaphase.
- Findings offer molecular insights into the function of PICH and related SNF2 proteins.
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