Gene-Specific Repair of 6-4 Photoproducts in Trichothiodystrophy Cells

  • Nathan, Sheila (Centre for Gene Analysis and Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia) ;
  • Van Hoffen, Anneke (Department of Radiation Genetics and Chemical Mutagenesis, State University of Leiden) ;
  • Mullenders, Leon H.F. (Department of Radiation Genetics and Chemical Mutagenesis, State University of Leiden) ;
  • Mayne, Lynne V. (Trafford Centre for Graduate Medical Research, University of Sussex)
  • Received : 0
  • Accepted : 0
  • Published : 0

Abstract

TTD1BI cells are non-hypersensitive to UV irradiation and perform normal genome repair of pyrimidine dimers but fail to excise 6-4 photoproducts and, concomitantly, are unable to restore RNA synthesis levels following UV irradiation. This pointed to a detect in gene-specific repair and this study was undertaken to examine repair of 6-4 photoproducts at the gene-level. The results indicated a defect in gene-specific repair of 6-4 photoproducts in active genes, although strand-specificity of 6-4 photoproduct removal was essentially similar to that of normal cells. These findings indicate that the near normal UV resistance of TTD1BI cells may be due to the inability of these cells to remove DNA lesions preferentially, as well as to the cells opting out of the cell cycle to repair damage before resuming replication.

Keywords

DNA repair;Gene-specific repair;Trichothiodystrophy;UV sensitivity