Di-methyl H4 Lysine 20 Targets the Checkpoint Protein Crb2 to Sites of DNA Damage

J Biol Chem. 2008 Nov 28;283(48):33168-74. doi: 10.1074/jbc.M806857200. Epub 2008 Sep 29.

Abstract

Histone lysine methylation is an important chromatin modification that can be catalyzed to a mono-, di-, or tri-methyl state. An ongoing challenge is to decipher how these different methyllysine histone marks can mediate distinct aspects of chromatin function. The fission yeast checkpoint protein Crb2 is rapidly targeted to sites of DNA damage after genomic insult, and this recruitment requires methylation of histone H4 lysine 20 (H4K20). Here we show that the tandem tudor domains of Crb2 preferentially bind the di-methylated H4K20 residue. Loss of this interaction by disrupting either the tudor-binding motif or the H4K20 methylating enzyme Set9/Kmt5 ablates Crb2 localization to double-strand breaks and impairs checkpoint function. Further we show that dimethylation, but not tri-methylation, of H4K20 is required for Crb2 localization, checkpoint function, and cell survival after DNA damage. These results argue that the di-methyl H4K20 modification serves as a binding target that directs Crb2 to sites of genomic lesions and defines an important genome integrity pathway mediated by a specific methyl-lysine histone mark.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs / physiology
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Chromatin / genetics
  • Chromatin / metabolism
  • DNA Damage / physiology*
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism*
  • Genome, Fungal / physiology
  • Genomic Instability / physiology
  • Histone Methyltransferases
  • Histone-Lysine N-Methyltransferase
  • Histones / genetics
  • Histones / metabolism*
  • Lysine / genetics
  • Lysine / metabolism
  • Methylation
  • Protein Binding / physiology
  • Protein Methyltransferases / genetics
  • Protein Methyltransferases / metabolism
  • Protein Processing, Post-Translational / physiology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • Cell Cycle Proteins
  • Chromatin
  • DNA, Fungal
  • Histones
  • Saccharomyces cerevisiae Proteins
  • Histone Methyltransferases
  • Protein Methyltransferases
  • Histone-Lysine N-Methyltransferase
  • Lysine