Impact of the KU80 pathway on NHEJ-induced genome rearrangements in mammalian cells

Mol Cell. 2004 Jun 4;14(5):611-23. doi: 10.1016/j.molcel.2004.05.008.


Using a substrate measuring deletion or inversion of an I-SceI-excised fragment and both accurate and inaccurate rejoining, we determined the impact of non-homologous end-joining (NHEJ) on mammalian chromosome rearrangements. Deletion is 2- to 8-fold more efficient than inversion, independent of the DNA ends structure. KU80 controls accurate rejoining, whereas in absence of KU mutagenic rejoining, particularly microhomology-mediated repair, occurs efficiently. In cells bearing both the NHEJ and a homologous recombination (HR) substrate containing a third I-SceI site, we show that NHEJ is at least 3.3-fold more efficient than HR, and translocation of the I-SceI fragment from the NHEJ substrate locus into the HR-I-SceI site can occur, but 50- to 100-fold less frequently than deletion. Deletions and translocations show both accurate and inaccurate rejoining, suggesting that they correspond to a mix of KU-dependent and KU-independent processes. Thus these processes should represent prominent pathways for DSB-induced genetic instability in mammalian cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Nuclear / genetics
  • Antigens, Nuclear / metabolism*
  • Base Sequence / genetics
  • CHO Cells
  • Cell Transformation, Neoplastic / genetics*
  • Cricetinae
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Deletion
  • Gene Rearrangement / genetics*
  • Genome*
  • Genomic Instability / genetics*
  • Ku Autoantigen
  • Mice
  • Molecular Sequence Data
  • Mutation / genetics*
  • Recombination, Genetic / genetics
  • Translocation, Genetic / genetics


  • Antigens, Nuclear
  • DNA-Binding Proteins
  • Xrcc6 protein, mouse
  • Ku Autoantigen