title: Efficient repair of cyclobutane pyrimidine dimers at mutational hot spots is restored in complemented Xeroderma pigmentosum group C and trichothiodystrophy/xeroderma pigmentosum group D cells.
abstract: Xeroderma pigmentosum (XP) and trichothiodystrophy (TTD) are rare heritable diseases. Patients suffering from XP and 50% of TTD afflicted individuals are photosensitive and have a high susceptibility to develop skin tumors. One solution to alleviating symptoms of these diseases is to express the deficient cDNAs in patient cells as a form of gene therapy. XPC and TTD/XPD cell lines were complemented using retroviral transfer. Expressed wild-type XPC or XPD cDNAs in these cells restored the survival to UVC radiation to wild-type levels in the respective complementation groups. Although complemented XP cell lines have been studied for years, data on cyclobutane pyrimidine dimer (CPD) repair in these cells at different levels are sparse. We demonstrate that CPD repair is faster in the complemented lines at the global, gene, strand specific, and nucleotide specific levels than in the original lines. In both XPC and TTD/XPD complemented lines, CPD repair on the non-transcribed strand is faster than that for the MRC5SV line. However, global repair in the complemented cell lines and MRC5SV is still slower than in normal human fibroblasts. Despite the slower global repair rate, in the complemented XPC and TTD/XPD cells, almost all of the CPDs at "hotspots" for mutation in the P53 tumor database are repaired as rapidly as in normal human fibroblasts. Such evaluation of repair at nucleotide resolution in complemented nucleotide excision repair deficient cells presents a crucial way to determine the efficient re-establishment of function needed for successful gene therapy, even when full repair capacity is not restored.
authors.affiliation: Department of Biology, Beckman Research Institute, City of Hope National Medical Center, 1450 East Duarte Road, Duarte, CA 91010, USA.
authors.forename: Ning Ye
authors.initials: NY
authors.lastname: Zhou
authors.forename: Steven E
authors.initials: SE
authors.lastname: Bates
authors.forename: Mohammed
authors.initials: M
authors.lastname: Bouziane
authors.forename: Anne
authors.initials: A
authors.lastname: Stary
authors.forename: Alain
authors.initials: A
authors.lastname: Sarasin
authors.forename: Timothy R
authors.initials: TR
authors.lastname: O'Connor
mesh_terms: D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D030561:Databases, Nucleic Acid; D005091:Exons; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology / Q000528:radiation effects; D016158:Genes, p53; D015316:Genetic Therapy; D006201:Hair Diseases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D011740:Pyrimidine Dimers / Q000378:metabolism*; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D011740:Pyrimidine Dimers