title: Pre-UV-treatment of cells results in enhanced host cell reactivation of a UV damaged reporter gene in CHO-AA8 chinese hamster ovary cells but not in transcription-coupled repair deficient CHO-UV61 cells.
abstract: We have used a non-replicating recombinant adenovirus, Ad5MCMVlacZ, which expresses the beta-galactosidase reporter gene, to examine both constitutive and inducible repair of UV-damaged DNA in repair proficient CHO-AA8 Chinese hamster ovary cells and in mutant CHO-UV61 cells which are deficient in the transcription-coupled repair (TCR) pathway of nucleotide excision repair. Host cell reactivation (HCR) of beta-galactosidase activity for UV-irradiated Ad5MCMVlacZ was significantly reduced in non-irradiated CHO-UV61 cells compared to that in non-irradiated CHO-AA8 cells suggesting that repair in the transcribed strand of the UV-damaged reporter gene in untreated cells utilizes TCR. Prior UV-irradiation of cells with low UV fluences resulted in a transient enhancement of HCR for expression of the UV-damaged reporter gene in CHO-AA8 cells but not in TCR deficient CHO-UV61 cells. These results suggest the presence of an inducible DNA pathway in CHO cells that results from an enhancement of TCR or a mechanism that involves the TCR pathway.
authors.affiliation: Department of Biology, McMaster University, L8S 4K1, Hamilton, Ontario, Canada, rainbow@mcmaster.ca.
authors.forename: Lili
authors.initials: L
authors.lastname: Liu
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Rainbow
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004260:DNA Repair / Q000235:genetics*; D005786:Gene Expression Regulation; D017930:Genes, Reporter / Q000528:radiation effects; D007763:Lac Operon / Q000528:radiation effects; D014158:Transcription, Genetic; D014466:Ultraviolet Rays; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D001616:beta-Galactosidase