title: Enzymatic recognition and biological effects of photodynamic damage induced in DNA by 1,6-dioxapyrene plus UVA.
abstract: The specific recognition of DNA modifications by repair endonucleases was used to characterize DNA damage induced by 1,6-dioxapyrene (1,6-DP) in the presence of ultraviolet light at 365 nm (UVA) in the plasmid YEplac181. Under cell free conditions, 1,6-DP plus UVA generated lesions are recognized by the UvrABC endonuclease, the proteins Nth, Nfo and Fpg. The number of UvrABC sensitive sites was at least ten-fold higher than that of Fpg or Nth sensitive sites. Moreover, 1,6-DP plus UVA generated single-strand breaks which are the second most frequent lesions. To investigate the biological effect of DNA damage, YEplac181 DNA was treated with 1,6-DP plus UVA and transformed into Escherichia coli or Saccharomyces cerevisiae. In Escherichia coli, the transformation efficiency of 1,6-DP plus UVA treated DNA was greatly reduced in the uvrA mutant compared to that in the wild-type strain. However, the transforming efficiency was not affected in Fpg-deficient strains. In Saccharomyces cerevisiae, the transformation efficiency of 1,6-DP plus UVA treated YEplac181 was greatly reduced in the rad14::URA3 strain. The photobiological effect of 1,6-DP plus UVA was also analysed in haploid yeast strains of various repair capacities. The results show that the yeast strain defective in the nucleotide excision repair pathway (rad14::URA3) is hypersensitive to 1,6-DP plus UVA treatment as compared to the parental wild-type strain. It is confirmed that the lethal effect of 1,6-DP plus UVA on wild-type yeast is strongly oxygen dependent, whereas the survival of the rad14::URA3 mutant only exhibits a minor oxygen dependence. To conclude, our data show that the photodynamic DNA lesions induced by 1,6-DP plus UVA can be recognized and repaired in pro- and eukaryotic cells by the nucleotide excision repair pathway.
authors.affiliation: Département de Radiobiologie et Radiopathologie, UMR217 Centre National de la Recherche Scientifique, Fontenay aux Roses, France.
authors.forename: M
authors.initials: M
authors.lastname: Padula
authors.forename: S
authors.initials: S
authors.lastname: Averbeck
authors.forename: S
authors.initials: S
authors.lastname: Boiteux
authors.forename: D
authors.initials: D
authors.lastname: Averbeck
mesh_terms: D019757:Carbon-Oxygen Lyases / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004278:DNA, Superhelical / Q000187:drug effects / Q000528:radiation effects; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043382:DNA-Formamidopyrimidine Glycosylase; D043224:Deoxyribonuclease (Pyrimidine Dimer); D043223:Deoxyribonuclease IV (Phage T4-Induced); D004706:Endodeoxyribonucleases / Q000378:metabolism*; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D009153:Mutagens / Q000494:pharmacology*; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D010957:Plasmids / Q000187:drug effects* / Q000528:radiation effects*; D011721:Pyrenes / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae; D014466:Ultraviolet Rays
chemical_list: D004278:DNA, Superhelical; D029968:Escherichia coli Proteins; D009153:Mutagens; D011721:Pyrenes; C081558:1,6-dioxapyrene; D004706:Endodeoxyribonucleases; D043223:Deoxyribonuclease IV (Phage T4-Induced); C468972:endonuclease IV, E coli; C036385:endodeoxyribonuclease uvrABC; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli; D009699:N-Glycosyl Hydrolases; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli; D019757:Carbon-Oxygen Lyases; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase