Repair of double-strand breaks by end joining

Cold Spring Harb Perspect Biol. 2013 May 1;5(5):a012757. doi: 10.1101/cshperspect.a012757.


Nonhomologous end joining (NHEJ) refers to a set of genome maintenance pathways in which two DNA double-strand break (DSB) ends are (re)joined by apposition, processing, and ligation without the use of extended homology to guide repair. Canonical NHEJ (c-NHEJ) is a well-defined pathway with clear roles in protecting the integrity of chromosomes when DSBs arise. Recent advances have revealed much about the identity, structure, and function of c-NHEJ proteins, but many questions exist regarding their concerted action in the context of chromatin. Alternative NHEJ (alt-NHEJ) refers to more recently described mechanism(s) that repair DSBs in less-efficient backup reactions. There is great interest in defining alt-NHEJ more precisely, including its regulation relative to c-NHEJ, in light of evidence that alt-NHEJ can execute chromosome rearrangements. Progress toward these goals is reviewed.

Publication types

  • Review

MeSH terms

  • DNA Breaks, Double-Stranded*
  • DNA End-Joining Repair*
  • DNA Ligase ATP
  • DNA Ligases / chemistry
  • DNA Ligases / physiology
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology
  • DNA-Directed DNA Polymerase / chemistry
  • DNA-Directed DNA Polymerase / physiology
  • Deoxyribonucleases / chemistry
  • Deoxyribonucleases / physiology
  • Histones / metabolism
  • Models, Genetic*
  • Mutation


  • DNA-Binding Proteins
  • Histones
  • DNA-Directed DNA Polymerase
  • Deoxyribonucleases
  • DNA Ligases
  • DNA Ligase ATP