Recruitment of Histone Methyltransferase Ehmt1 to Foxp3 TSDR Counteracts Differentiation of Induced Regulatory T Cells

J Mol Biol. 2019 Sep 6;431(19):3606-3625. doi: 10.1016/j.jmb.2019.07.031. Epub 2019 Jul 27.

Abstract

Differentiation toward CD4+ regulatory T (Treg) cells is essentially dependent on an epigenetic program at Treg signature genes, which involves remodeling of the Treg-specific demethylated regions (TSDRs). In particular, the epigenetic status of the conserved non-coding sequence 2 of Foxp3 (Foxp3 TSDR) determines expression stability of the master transcription factor and thus Treg lineage identity. However, the molecular mechanisms controlling the epigenetic remodeling at TSDRs in Treg and conventional T cells are largely unknown. Using a combined approach of DNA pull-down and mass spectrometric analysis, we report a novel regulatory mechanism in which transcription factor Wiz recruits the histone methyltransferase Ehmt1 to Foxp3 TSDR. We show that both Wiz and Ehmt1 are crucial for shaping the region with the repressive histone modification H3K9me2 in conventional T cells. Consistently, knocking out either Ehmt1 or Wiz by CRISPR/Cas resulted in the loss of H3K9me2 and enhanced Foxp3 expression during iTreg differentiation. Moreover, the essential role of the Wiz-Ehmt1 interaction as observed at several TSDRs indicates a global function of Ehmt1 in the Treg differentiation program.

Keywords: DNA-pull down; T helper cell; ascorbate; epigenetics; mass spectrometry; vitamin C.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ascorbic Acid / pharmacology
  • Base Sequence
  • Cell Differentiation / drug effects
  • Cell Differentiation / genetics
  • DNA Methylation / drug effects
  • DNA Methylation / genetics
  • Demethylation
  • Epigenesis, Genetic / drug effects
  • Forkhead Transcription Factors / metabolism*
  • Histone-Lysine N-Methyltransferase / metabolism*
  • Histones / metabolism
  • Kruppel-Like Transcription Factors / metabolism
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Models, Genetic
  • Nerve Tissue Proteins / metabolism
  • T-Lymphocytes, Regulatory / drug effects
  • T-Lymphocytes, Regulatory / metabolism*

Substances

  • Forkhead Transcription Factors
  • Foxp3 protein, mouse
  • Histones
  • Kruppel-Like Transcription Factors
  • Nerve Tissue Proteins
  • Wiz protein, mouse
  • G9a protein, mouse
  • GLP protein, mouse
  • Histone-Lysine N-Methyltransferase
  • Ascorbic Acid