Chromatin dynamics: Nucleosomes go mobile through twist defects

TL;DR

This paper models the spontaneous movement of nucleosomes along DNA via thermally activated twist defects, revealing how sequence influences mobility, using an extended Frenkel-Kontorova model calibrated with experimental data.

Contribution

It introduces a novel theoretical model linking nucleosome mobility to DNA sequence through twist defect dynamics, validated by experimental estimates.

Findings

Nucleosome sliding can be explained by thermally activated twist defects.

Sequence-dependent variations significantly affect nucleosome mobility.

The model accurately estimates mobility without adjustable parameters.

Abstract

We study the spontaneous ''sliding'' of histone spools (nucleosomes) along DNA as a result of thermally activated single base pair twist defects. To this end we map the system onto a suitably extended Frenkel-Kontorova model. Combining results from several recent experiments we are able to estimate the nucleosome mobility without adjustable parameters. Our model shows also how the local mobility is intimately linked to the underlying base pair sequence.