Epigenetic memory independent of symmetric histone inheritance

Elife. 2019 Oct 15;8:e51421. doi: 10.7554/eLife.51421.

Abstract

Heterochromatic gene silencing is an important form of gene regulation that usually requires specific histone modifications. A popular model posits that inheritance of modified histones, especially in the form of H3-H4 tetramers, underlies inheritance of heterochromatin. Because H3-H4 tetramers are randomly distributed between daughter chromatids during DNA replication, rare occurrences of asymmetric tetramer inheritance within a heterochromatic domain would have the potential to destabilize heterochromatin. This model makes a prediction that shorter heterochromatic domains would experience unbalanced tetramer inheritance more frequently, and thereby be less stable. In contrast to this prediction, we found that shortening a heterochromatic domain in Saccharomyces had no impact on the strength of silencing nor its heritability. Additionally, we found that replisome mutations that disrupt inheritance of H3-H4 tetramers had only minor effects on heterochromatin stability. These findings suggest that histones carry little or no memory of the heterochromatin state through DNA replication.

Keywords: S. cerevisiae; chromosomes; epigenetics; gene expression; heterochromatin; histones.

Publication types

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

MeSH terms

  • Biopolymers / chemistry
  • Biopolymers / metabolism
  • DNA Replication
  • Epigenesis, Genetic*
  • Gene Silencing
  • Heterochromatin / genetics
  • Heterochromatin / metabolism
  • Histones / chemistry
  • Histones / metabolism*
  • Yeasts / genetics

Substances

  • Biopolymers
  • Heterochromatin
  • Histones

Associated data

  • GEO/GSE136897