Mammalian Ino80 mediates double-strand break repair through its role in DNA end strand resection

Mol Cell Biol. 2011 Dec;31(23):4735-45. doi: 10.1128/MCB.06182-11. Epub 2011 Sep 26.


Chromatin modifications/remodeling are important mechanisms by which cells regulate various functions through providing accessibility to chromatin DNA. Recent studies implicated INO80, a conserved chromatin-remodeling complex, in the process of DNA repair. However, the precise underlying mechanism by which this complex mediates repair in mammalian cells remains enigmatic. Here, we studied the effect of silencing of the Ino80 subunit of the complex on double-strand break repair in mammalian cells. Comet assay and homologous recombination repair reporter system analyses indicated that Ino80 is required for efficient double-strand break repair. Ino80 association with chromatin surrounding double-strand breaks suggested the direct involvement of INO80 in the repair process. Ino80 depletion impaired focal recruitment of 53BP1 but did not impede Rad51 focus formation, suggesting that Ino80 is required for the early steps of repair. Further analysis by using bromodeoxyuridine (BrdU)-labeled single-stranded DNA and replication protein A (RPA) immunofluorescent staining showed that INO80 mediates 5'-3' resection of double-strand break ends.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATPases Associated with Diverse Cellular Activities
  • Animals
  • Cell Line
  • Chromatin / metabolism
  • Chromatin / radiation effects
  • Comet Assay
  • DNA / metabolism
  • DNA / radiation effects
  • DNA Breaks, Double-Stranded*
  • DNA Helicases / genetics
  • DNA Helicases / metabolism*
  • DNA Repair*
  • DNA, Single-Stranded / metabolism
  • DNA-Binding Proteins
  • Embryonic Stem Cells / metabolism
  • Embryonic Stem Cells / radiation effects
  • Gene Knockdown Techniques
  • Histones / metabolism
  • Homologous Recombination
  • Humans
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Male
  • Mice
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism
  • Phosphorylation
  • RNA Interference
  • Replication Protein A / metabolism
  • Tumor Suppressor p53-Binding Protein 1


  • ACTR8 protein, human
  • Chromatin
  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • Histones
  • Intracellular Signaling Peptides and Proteins
  • Microfilament Proteins
  • Replication Protein A
  • TP53BP1 protein, human
  • Tumor Suppressor p53-Binding Protein 1
  • DNA
  • ATPases Associated with Diverse Cellular Activities
  • DNA Helicases
  • INO80 protein, human