DNA Double-Strand Break Resection Occurs during Non-homologous End Joining in G1 but Is Distinct from Resection during Homologous Recombination

Mol Cell. 2017 Feb 16;65(4):671-684.e5. doi: 10.1016/j.molcel.2016.12.016. Epub 2017 Jan 26.

Abstract

Canonical non-homologous end joining (c-NHEJ) repairs DNA double-strand breaks (DSBs) in G1 cells with biphasic kinetics. We show that DSBs repaired with slow kinetics, including those localizing to heterochromatic regions or harboring additional lesions at the DSB site, undergo resection prior to repair by c-NHEJ and not alt-NHEJ. Resection-dependent c-NHEJ represents an inducible process during which Plk3 phosphorylates CtIP, mediating its interaction with Brca1 and promoting the initiation of resection. Mre11 exonuclease, EXD2, and Exo1 execute resection, and Artemis endonuclease functions to complete the process. If resection does not commence, then repair can ensue by c-NHEJ, but when executed, Artemis is essential to complete resection-dependent c-NHEJ. Additionally, Mre11 endonuclease activity is dispensable for resection in G1. Thus, resection in G1 differs from the process in G2 that leads to homologous recombination. Resection-dependent c-NHEJ significantly contributes to the formation of deletions and translocations in G1, which represent important initiating events in carcinogenesis.

Keywords: DNA double-strand breaks; non-homologous end joining; nucleases; resection.

Publication types

  • Comparative Study

MeSH terms

  • BRCA1 Protein / genetics
  • BRCA1 Protein / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Nucleus / enzymology
  • Cell Nucleus / pathology
  • Cell Nucleus / radiation effects*
  • DNA Breaks, Double-Stranded*
  • DNA End-Joining Repair / radiation effects*
  • DNA Repair Enzymes / genetics
  • DNA Repair Enzymes / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Endodeoxyribonucleases
  • Endonucleases
  • Exodeoxyribonucleases / genetics
  • Exodeoxyribonucleases / metabolism
  • G1 Phase / radiation effects*
  • G2 Phase
  • Gene Deletion
  • HeLa Cells
  • Humans
  • Kinetics
  • MRE11 Homologue Protein
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Time Factors
  • Transfection
  • Translocation, Genetic
  • Tumor Suppressor p53-Binding Protein 1 / genetics
  • Tumor Suppressor p53-Binding Protein 1 / metabolism

Substances

  • BRCA1 Protein
  • BRCA1 protein, human
  • Carrier Proteins
  • DNA-Binding Proteins
  • MRE11 protein, human
  • Nuclear Proteins
  • TP53BP1 protein, human
  • Tumor Suppressor p53-Binding Protein 1
  • PLK3 protein, human
  • Protein-Serine-Threonine Kinases
  • DCLRE1C protein, human
  • EXO1 protein, human
  • Endodeoxyribonucleases
  • Endonucleases
  • Exodeoxyribonucleases
  • MRE11 Homologue Protein
  • RBBP8 protein, human
  • DNA Repair Enzymes