title: Increased expression of p53 enhances transcription-coupled repair and global genomic repair of a UVC-damaged reporter gene in human cells.
abstract: Ultraviolet (UV) light-induced DNA damage is repaired by nucleotide excision repair, which is divided into two sub-pathways: global genome repair (GGR) and transcription-coupled repair (TCR). While it is well established that the GGR pathway is dependent on the p53 tumour suppressor protein in human cells, both p53-dependent and p53-independent pathways have been reported for TCR. In the present work, we investigated the role of p53 in both GGR and TCR of a UVC-damaged reporter gene in human fibroblasts. We employed a non-replicating recombinant human adenovirus, AdCA17lacZ, that can efficiently infect human fibroblasts and express the beta-galactosidase (beta-gal) reporter gene under the control of the human cytomegalovirus promoter. We examined host cell reactivation (HCR) of beta-gal expression for the UVC-treated reporter construct in normal fibroblasts and in xeroderma pigmentosum (XP) and Cockayne syndrome (CS) fibroblasts deficient in GGR, TCR, or both. HCR was examined in fibroblasts that had been pre-infected with Ad5p53wt, which expresses wild-type p53, or a control adenovirus, AdCA18luc, which expresses the luciferase gene. We show that increased expression of p53 results in enhanced HCR of the UVC-damaged reporter gene in both untreated and UVC-treated cells for normal, CS-B (TCR-deficient), and XP-C (GGR-deficient), but not XP-A (TCR- and GGR-deficient) fibroblasts. These results indicate an involvement of p53 in both TCR and GGR of the UV-damaged reporter gene in human cells.
authors.affiliation: Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
authors.forename: Diana
authors.initials: D
authors.lastname: Dregoesc
authors.forename: Adrian P
authors.initials: AP
authors.lastname: Rybak
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Rainbow
mesh_terms: D000260:Adenoviruses, Human / Q000235:genetics / Q000528:radiation effects; D015153:Blotting, Western; D002478:Cells, Cultured / Q000502:physiology / Q000528:radiation effects; D003057:Cockayne Syndrome / Q000235:genetics* / Q000473:pathology; D004249:DNA Damage; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D005347:Fibroblasts / Q000187:drug effects / Q000473:pathology; D005786:Gene Expression Regulation / Q000528:radiation effects; D016678:Genome; D006801:Humans; D007763:Lac Operon / Q000528:radiation effects; D014158:Transcription, Genetic; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000235:genetics* / Q000473:pathology; D051760:Xeroderma Pigmentosum Group A Protein / Q000235:genetics / Q000502:physiology; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D016159:Tumor Suppressor Protein p53; C497314:XPA protein, human; D051760:Xeroderma Pigmentosum Group A Protein; C086984:XPC protein, human; D001616:beta-Galactosidase; D045643:DNA Repair Enzymes