Coordination of dual incision and repair synthesis in human nucleotide excision repair

EMBO J. 2009 Apr 22;28(8):1111-20. doi: 10.1038/emboj.2009.49. Epub 2009 Mar 12.


Nucleotide excision repair (NER) requires the coordinated sequential assembly and actions of the involved proteins at sites of DNA damage. Following damage recognition, dual incision 5' to the lesion by ERCC1-XPF and 3' to the lesion by XPG leads to the removal of a lesion-containing oligonucleotide of about 30 nucleotides. The resulting single-stranded DNA (ssDNA) gap on the undamaged strand is filled in by DNA repair synthesis. Here, we have asked how dual incision and repair synthesis are coordinated in human cells to avoid the exposure of potentially harmful ssDNA intermediates. Using catalytically inactive mutants of ERCC1-XPF and XPG, we show that the 5' incision by ERCC1-XPF precedes the 3' incision by XPG and that the initiation of repair synthesis does not require the catalytic activity of XPG. We propose that a defined order of dual incision and repair synthesis exists in human cells in the form of a 'cut-patch-cut-patch' mechanism. This mechanism may aid the smooth progression through the NER pathway and contribute to genome integrity.

Publication types

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

MeSH terms

  • Animals
  • Catalytic Domain
  • Cell Line
  • DNA / genetics
  • DNA / metabolism*
  • DNA / radiation effects
  • DNA Damage*
  • DNA Repair*
  • DNA, Single-Stranded / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Endonucleases / genetics
  • Endonucleases / metabolism
  • Humans
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Proliferating Cell Nuclear Antigen / genetics
  • Proliferating Cell Nuclear Antigen / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Ultraviolet Rays


  • CNOT8 protein, human
  • DNA excision repair protein ERCC-5
  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Proliferating Cell Nuclear Antigen
  • Transcription Factors
  • xeroderma pigmentosum group F protein
  • DNA
  • ERCC1 protein, human
  • Endonucleases