Histone methyltransferases G9a and GLP form heteromeric complexes and are both crucial for methylation of euchromatin at H3-K9

Genes Dev. 2005 Apr 1;19(7):815-26. doi: 10.1101/gad.1284005. Epub 2005 Mar 17.

Abstract

Histone H3 Lys 9 (H3-K9) methylation is a crucial epigenetic mark for transcriptional silencing. G9a is the major mammalian H3-K9 methyltransferase that targets euchromatic regions and is essential for murine embryogenesis. There is a single G9a-related methyltransferase in mammals, called GLP/Eu-HMTase1. Here we show that GLP is also important for H3-K9 methylation of mouse euchromatin. GLP-deficiency led to embryonic lethality, a severe reduction of H3-K9 mono- and dimethylation, the induction of Mage-a gene expression, and HP1 relocalization in embryonic stem cells, all of which were phenotypes of G9a-deficiency. Furthermore, we show that G9a and GLP formed a stoichiometric heteromeric complex in a wide variety of cell types. Biochemical analyses revealed that formation of the G9a/GLP complex was dependent on their enzymatic SET domains. Taken together, our new findings revealed that G9a and GLP cooperatively exert H3-K9 methyltransferase function in vivo, likely through the formation of higher-order heteromeric complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Euchromatin / enzymology*
  • Histone Methyltransferases
  • Histone-Lysine N-Methyltransferase / chemistry*
  • Histone-Lysine N-Methyltransferase / metabolism
  • Histones / metabolism*
  • Lysine / metabolism*
  • Methylation
  • Mice
  • Protein Methyltransferases
  • Protein Structure, Quaternary
  • Stem Cells / enzymology

Substances

  • Euchromatin
  • Histones
  • Histone Methyltransferases
  • Protein Methyltransferases
  • GLP protein, mouse
  • Histone-Lysine N-Methyltransferase
  • Lysine