A novel disrupter of telomere silencing 1-like (DOT1L) interaction is required for signal transducer and activator of transcription 1 (STAT1)-activated gene expression

J Biol Chem. 2011 Dec 2;286(48):41195-41204. doi: 10.1074/jbc.M111.284190. Epub 2011 Oct 15.

Abstract

JAK-STAT-activated gene expression is both rapid and transient and requires dynamic post-translational modification of the chromatin template. Previously, we showed that following IFN-γ treatment, trimethylation of histone H3 at lysine 79 (H3K79me3) is rapidly and highly induced in the 5'-end of the STAT1-dependent gene interferon regulatory factor 1 (IRF1), but the role of this histone modification was unexplored. Here we report that DOT1L, the non-SET domain containing methyltransferase that modifies Lys-79, is localized across IRF1 in the uninduced state and is not further recruited by IFN-γ induction. RNAi-mediated depletion of DOT1L prevents the induction of H3K79me3 and lowers the transcription of IRF1 2-fold, as expected. Surprisingly, STAT1 binding to its DNA recognition element near the IRF1 promoter is diminished 2-fold in the DOT1L-depleted cell line. In vivo and in vitro protein interaction assays reveal a DOT1L-STAT1 interaction. Domain mapping identifies the middle region of DOT1L (amino acids 580-1183) as the STAT1 interaction domain. Overexpression of the DOT1L STAT1 interaction domain represses IRF1 transcription (2-fold) and interferes with STAT1 DNA binding at IRF1 and endogenous DOT1L histone methyltransferase activity. Collectively, our findings reveal a novel STAT1-DOT1L interaction that is required for the regulation JAK-STAT-inducible gene expression.

MeSH terms

  • Cell Line
  • Gene Expression Regulation / physiology*
  • Histone-Lysine N-Methyltransferase
  • Histones / genetics
  • Histones / metabolism
  • Humans
  • Interferon Regulatory Factor-1 / biosynthesis
  • Interferon Regulatory Factor-1 / genetics
  • Methyltransferases / genetics
  • Methyltransferases / metabolism*
  • Peptide Mapping
  • Protein Structure, Tertiary
  • Response Elements / physiology
  • STAT1 Transcription Factor / genetics
  • STAT1 Transcription Factor / metabolism*
  • Transcription, Genetic / physiology*

Substances

  • Histones
  • IRF1 protein, human
  • Interferon Regulatory Factor-1
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • DOT1L protein, human
  • Methyltransferases
  • Histone-Lysine N-Methyltransferase