Differential requirement for the ATPase domain of the Cockayne syndrome group B gene in the processing of UV-induced DNA damage and 8-oxoguanine lesions in human cells

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Selzer R., Nyaga S., Tuo J., May A., Muftuoglu M., Christiansen M., ...More

NUCLEIC ACIDS RESEARCH, vol.30, no.3, pp.782-793, 2002 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 30 Issue: 3
  • Publication Date: 2002
  • Doi Number: 10.1093/nar/30.3.782
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.782-793
  • Hacettepe University Affiliated: No


Cockayne syndrome (CS) is a rare inherited human genetic disorder characterized by UV sensitivity, developmental abnormalities and premature aging. The cellular and molecular phenotypes of CS include increased sensitivity to oxidative and UV-induced DNA lesions. The CSB protein is thought to play a pivotal role in transcription-coupled repair and CS-B cells are defective in the repair of the transcribed strand of active genes, both after exposure to UV and in the presence of oxidative DNA lesions. A previous study has indicated that a conserved helicase ATPase motif II residue is essential for the function of the CSB protein in responding to UV-induced DNA damage in a hamster cell line. Due to the limitations in studying a complex human disorder in another species, this study introduced the site-directed mutation of the ATPase motif II in the human CSB gene in an isogenic human cell line. The CSB mutant allele was tested for genetic complementation of UV-sensitive phenotypes in the human CS-B cell line CS1AN.S3.G2. In addition, the incision of an 8-oxoguanine lesion by extracts of the CS-B cell lines stably transfected with the wild-type or ATPase mutant CSB gene has been investigated. The ATPase motif II point mutation (E646Q) abolished the function of the CSB protein to complement the UV-sensitive phenotypes of survival, RNA synthesis recovery and apoptosis. Interestingly, whole-cell extract prepared from these mutant cells retained wild-type incision activity on an oligonucleotide containing a single 8-oxoguanine lesion, whereas the absence of the CSB gene altogether resulted in reduced incision activity relative to wild-type. These results suggest damage-specific functional requirements for CSB in the repair of UV-induced and oxidative lesions in human cells. The transfection of the mutant or wild-type CSB gene into the CS1AN.S3.G2 cells did not alter the expression of the subset of genes examined by cDNA array analysis.