Definition of a short region of XPG necessary for TFIIH interaction and stable recruitment to sites of UV damage

Mol Cell Biol. 2004 Dec;24(24):10670-80. doi: 10.1128/MCB.24.24.10670-10680.2004.


XPG is the human endonuclease that cuts 3' to DNA lesions during nucleotide excision repair. Missense mutations in XPG can lead to xeroderma pigmentosum (XP), whereas truncated or unstable XPG proteins cause Cockayne syndrome (CS), normally yielding life spans of <7 years. One XP-G individual who had advanced XP/CS symptoms at 28 years has been identified. The genetic, biochemical, and cellular defects in this remarkable case provide insight into the onset of XP and CS, and they reveal a previously unrecognized property of XPG. Both of this individual's XPG alleles produce a severely truncated protein, but an infrequent alternative splice generates an XPG protein lacking seven internal amino acids, which can account for his very slight cellular UV resistance. Deletion of XPG amino acids 225 to 231 does not abolish structure-specific endonuclease activity. Instead, this region is essential for interaction with TFIIH and for the stable recruitment of XPG to sites of local UV damage after the prior recruitment of TFIIH. These results define a new functional domain of XPG, and they demonstrate that recruitment of DNA repair proteins to sites of damage does not necessarily lead to productive repair reactions. This observation has potential implications that extend beyond nucleotide excision repair.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Cell Line
  • Cell Line, Transformed
  • Cell Transformation, Viral
  • DNA Damage / radiation effects*
  • DNA Mutational Analysis
  • DNA Repair
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Endonucleases / analysis
  • Endonucleases / metabolism
  • Fibroblasts / metabolism
  • Fibroblasts / radiation effects
  • Fluorescent Antibody Technique, Indirect
  • Frameshift Mutation
  • Humans
  • Immunoblotting
  • Lentivirus / genetics
  • Longevity
  • Male
  • Microscopy, Fluorescence
  • Nuclear Proteins
  • Precipitin Tests
  • Protein Structure, Tertiary
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Transcription Factor TFIIH
  • Transcription Factors
  • Transcription Factors, TFII / metabolism*
  • Ultraviolet Rays*
  • Xeroderma Pigmentosum / diagnosis
  • Xeroderma Pigmentosum / genetics
  • Xeroderma Pigmentosum / metabolism
  • Xeroderma Pigmentosum / pathology


  • DNA excision repair protein ERCC-5
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Recombinant Proteins
  • Transcription Factors
  • Transcription Factors, TFII
  • Transcription Factor TFIIH
  • Endonucleases