XPG endonuclease makes the 3' incision in human DNA nucleotide excision repair

Nature. 1994 Sep 29;371(6496):432-5. doi: 10.1038/371432a0.


Humans with a defect in the XPG protein suffer from xeroderma pigmentosum (XP) resulting from an inability to perform DNA nucleotide excision repair properly. Here we show that XPG makes a structure-specific endonucleolytic incision in a synthetic DNA substrate containing a duplex region and single-stranded arms. One strand of the duplex is cleaved at the border with single-stranded DNA. A cut with the same polarity is also made in a bubble structure, at the 3' side of the centrally unpaired region. Normal cell extracts introduce a nick 3' to a platinum-DNA lesion, but an XP-G cell extract is defective in making this incision. These data show that XPG has a direct role in making one of the incisions required to excise a damaged oligonucleotide, by cleaving 3' to DNA damage during nucleotide excision repair.

MeSH terms

  • Base Sequence
  • DNA Repair*
  • DNA, Single-Stranded / metabolism
  • DNA-Binding Proteins*
  • Endodeoxyribonucleases*
  • Endonucleases / metabolism*
  • Escherichia coli
  • Fungal Proteins / metabolism
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins*
  • Xeroderma Pigmentosum / enzymology*
  • Xeroderma Pigmentosum / genetics


  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • Fungal Proteins
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • RAD2 protein, S cerevisiae
  • Endodeoxyribonucleases
  • Endonucleases
  • DNA-specific endonuclease (xeroderma pigmentosum)