Supramolecular multilayer organization of chromosomes: possible functional roles of planar chromatin in gene expression and DNA replication and repair

FEBS Lett. 2020 Feb;594(3):395-411. doi: 10.1002/1873-3468.13724. Epub 2020 Jan 8.

Abstract

Experimental evidence indicates that the chromatin filament is self-organized into a multilayer planar structure that is densely stacked in metaphase and unstacked in interphase. This chromatin organization is unexpected, but it is shown that diverse supramolecular assemblies, including dinoflagellate chromosomes, are multilayered. The mechanical strength of planar chromatin protects the genome integrity, even when double-strand breaks are produced. Here, it is hypothesized that the chromatin filament in the loops and topologically associating domains is folded within the thin layers of the multilaminar chromosomes. It is also proposed that multilayer chromatin has two states: inactive when layers are stacked and active when layers are unstacked. Importantly, the well-defined topology of planar chromatin may facilitate DNA replication without entanglements and DNA repair by homologous recombination.

Keywords: DNA repair; DNA replication; cell cycle; chromatin structure; chromosome structure; gene expression; homologous recombination repair; multilayered planar chromatin; supramolecular chromatin structure; topologically associating domains.

Publication types

  • Review

MeSH terms

  • Animals
  • Biomechanical Phenomena
  • Chromatin / genetics
  • Chromatin / metabolism*
  • DNA Repair*
  • DNA Replication*
  • Gene Expression Regulation*
  • Humans
  • Mitosis

Substances

  • Chromatin