Histone H1 protects telomeric repeats from H3K27me3 invasion in Arabidopsis

Cell Rep. 2023 Aug 29;42(8):112894. doi: 10.1016/j.celrep.2023.112894. Epub 2023 Jul 28.


While the pivotal role of linker histone H1 in shaping nucleosome organization is well established, its functional interplays with chromatin factors along the epigenome are just starting to emerge. Here we show that, in Arabidopsis, as in mammals, H1 occupies Polycomb Repressive Complex 2 (PRC2) target genes where it favors chromatin condensation and H3K27me3 deposition. We further show that, contrasting with its conserved function in PRC2 activation at genes, H1 selectively prevents H3K27me3 accumulation at telomeres and large pericentromeric interstitial telomeric repeat (ITR) domains by restricting DNA accessibility to Telomere Repeat Binding (TRB) proteins, a group of H1-related Myb factors mediating PRC2 cis recruitment. This study provides a mechanistic framework by which H1 avoids the formation of gigantic H3K27me3-rich domains at telomeric sequences and contributes to safeguard nucleus architecture.

Keywords: 3D chromosome organization; Arabidopsis; CP: Molecular biology; CP: Plants; H3K27me3; Polycomb; TRB; Telomere Repeat Binding protein; chromatin accessibility; linker histone H1; telomere.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arabidopsis Proteins* / genetics
  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / genetics
  • Arabidopsis* / metabolism
  • Chromatin
  • Histones / metabolism
  • Mammals / metabolism
  • Polycomb Repressive Complex 2 / metabolism
  • Telomere / genetics
  • Telomere / metabolism
  • Telomere-Binding Proteins / metabolism


  • Histones
  • Chromatin
  • Arabidopsis Proteins
  • Polycomb Repressive Complex 2
  • Telomere-Binding Proteins