Liquid-like interactions in heterochromatin: Implications for mechanism and regulation

Curr Opin Cell Biol. 2020 Jun:64:90-96. doi: 10.1016/j.ceb.2020.03.004. Epub 2020 May 17.

Abstract

A large portion of the eukaryotic genome is packed into heterochromatin, a versatile platform that is essential to maintain genome stability. Often associated with a compact and transcriptionally repressed chromatin state, heterochromatin was earlier considered a static and locked compartment. However, cumulative findings over the last 17 years have suggested that heterochromatin displays dynamics at different timescales and size scales. These dynamics are thought to be essential for the regulation of heterochromatin. This review illustrates how the key principles underlying heterochromatin structure and function have evolved along the years and summarizes the discoveries that have led to the continuous revision of these principles. Using heterochromatin protein 1-mediated heterochromatin as a context, we discuss a novel paradigm for heterochromatin organization based on two emerging concepts, phase separation and nucleosome structural plasticity. We also examine the broader implications of this paradigm for chromatin organization and regulation beyond heterochromatin.

Keywords: Biomolecular condensate; Chromatin; Dynamics; Heterochromatin; Nucleosome; Phase separation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Chromobox Protein Homolog 5
  • Chromosomal Proteins, Non-Histone / metabolism
  • Genomic Instability
  • Heterochromatin / metabolism*
  • Humans
  • Models, Biological
  • Nucleosomes / metabolism

Substances

  • Chromosomal Proteins, Non-Histone
  • Heterochromatin
  • Nucleosomes
  • Chromobox Protein Homolog 5