Concerted activities of distinct H4K20 methyltransferases at DNA double-strand breaks regulate 53BP1 nucleation and NHEJ-directed repair

Cell Rep. 2014 Jul 24;8(2):430-8. doi: 10.1016/j.celrep.2014.06.013. Epub 2014 Jul 4.

Abstract

Although selective binding of 53BP1 to dimethylated histone H4 lysine 20 (H4K20me2) at DNA double-strand breaks (DSBs) is a necessary and pivotal determinant of nonhomologous end joining (NHEJ)-directed repair, the enzymes that generate H4K20me2 at DSBs were unclear. Here, we determined that the PR-Set7 monomethyltransferase (H4K20me1) regulates de novo H4K20 methylation at DSBs. Rapid recruitment of PR-Set7 to DSBs was dependent on the NHEJ Ku70 protein and necessary for NHEJ-directed repair. PR-Set7 monomethyltransferase activity was required, but insufficient, for H4K20me2 and 53BP1 nucleation at DSBs. We determined that PR-Set7-mediated H4K20me1 facilitates Suv4-20 methyltransferase recruitment and catalysis to generate H4K20me2 necessary for 53BP1 binding. The orchestrated and concerted activities of PR-Set7 and Suv4-20 were required for proficient 53BP1 nucleation and DSB repair. This report identifies PR-Set7 as an essential component of NHEJ and implicates PR-Set7 as a central determinant of NHEJ-directed repair early in mammalian DSB repair pathway choice.

Publication types

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

MeSH terms

  • Active Transport, Cell Nucleus
  • Cell Nucleus / metabolism*
  • DNA Breaks, Double-Stranded*
  • DNA End-Joining Repair*
  • HEK293 Cells
  • HeLa Cells
  • Histone-Lysine N-Methyltransferase / metabolism*
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Protein Binding
  • Tumor Suppressor p53-Binding Protein 1

Substances

  • Intracellular Signaling Peptides and Proteins
  • TP53BP1 protein, human
  • Tumor Suppressor p53-Binding Protein 1
  • Histone-Lysine N-Methyltransferase