The Linker Histone GH1-HMGA1 Is Involved in Telomere Stability and DNA Damage Repair

Plant Physiol. 2018 May;177(1):311-327. doi: 10.1104/pp.17.01789. Epub 2018 Apr 5.


Despite intensive searches, few proteins involved in telomere homeostasis have been identified in plants. Here, we used pull-down assays to identify potential telomeric interactors in the model plant species Arabidopsis (Arabidopsis thaliana). We identified the candidate protein GH1-HMGA1 (also known as HON4), an uncharacterized linker histone protein of the High Mobility Group Protein A (HMGA) family in plants. HMGAs are architectural transcription factors and have been suggested to function in DNA damage repair, but their precise biological roles remain unclear. Here, we show that GH1-HMGA1 is required for efficient DNA damage repair and telomere integrity in Arabidopsis. GH1-HMGA1 mutants exhibit developmental and growth defects, accompanied by ploidy defects, increased telomere dysfunction-induced foci, mitotic anaphase bridges, and degraded telomeres. Furthermore, mutants have a higher sensitivity to genotoxic agents such as mitomycin C and γ-irradiation. Our work also suggests that GH1-HMGA1 is involved directly in the repair process by allowing the completion of homologous recombination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / growth & development
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Chromatin / metabolism
  • DNA Damage*
  • DNA Repair*
  • DNA, Bacterial / genetics
  • Fluorescence
  • HMGA Proteins / metabolism*
  • Histones / metabolism*
  • Homologous Recombination / genetics
  • Mutation / genetics
  • Protein Binding
  • Telomerase / metabolism
  • Telomere / metabolism*
  • Telomere-Binding Proteins / metabolism


  • Arabidopsis Proteins
  • Chromatin
  • DNA, Bacterial
  • HMGA Proteins
  • HON4 protein, Arabidopsis
  • Histones
  • T-DNA
  • Telomere-Binding Proteins
  • Telomerase