Extensile motor activity drives coherent motions in a model of interphase chromatin

David Saintillan, Michael J. Shelley, Alexandra Zidovska

Research output: Contribution to journalArticlepeer-review

Abstract

The 3D spatiotemporal organization of the human genome inside the cell nucleus remains a major open question in cellular biology. In the time between two cell divisions, chromatin-the functional form of DNA in cells-fills the nucleus in its uncon-densed polymeric form. Recent in vivo imaging experiments reveal that the chromatin moves coherently, having displacements with long-ranged correlations on the scale of micrometers and lasting for seconds. To elucidate the mechanism(s) behind these motions, we develop a coarse-grained active polymer model where chromatin is represented as a confined flexible chain acted upon by molecular motors that drive fluid flows by exerting dipolar forces on the system. Numerical simulations of this model account for steric and hydrodynamic interactions as well as internal chain mechanics. These demonstrate that coherent motions emerge in systems involving extensile dipoles and are accompanied by large-scale chain reconfigurations and nematic ordering. Comparisons with experiments show good qualitative agreement and support the hypothesis that self-organizing long-ranged hydrodynamic couplings between chromatin-associated active motor proteins are responsible for the observed coherent dynamics.

Original languageEnglish (US)
Pages (from-to)11442-11447
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Issue number45
DOIs
StatePublished - Nov 6 2018

Keywords

  • Active matter
  • Chromatin
  • Nucleoplasm
  • Polymer dynamics

ASJC Scopus subject areas

  • General

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