Base modification and strand breakage in isolated calf thymus DNA and in DNA from human skin epidermal keratinocytes exposed to peroxynitrite or 3-morpholinosydnonimine.
Exposure of isolated calf thymus DNA and human skin epidermal keratinocytes to peroxynitrite or the peroxynitrite generator, 3-morpholinosydnonimine (SIN-1), led to extensive DNA base modification. Large increases in xanthine and hypoxanthine, possible deamination products of guanine and adenine, respectively, and in 8-nitroguanine were observed, but only small changes in some oxidized base products were seen. This pattern of damage suggests that hydroxyl radicals were not major contributors to base modification caused by peroxynitrite, as OH is known to cause multiple oxidative modifications to all four DNA bases. Instead, it seems that reactive nitrogen species play a much greater role in the mechanism of base damage, producing both nitration and deamination of purine bases when DNA or whole cells are exposed to peroxynitrite. If this pattern of damage is unique to peroxynitrite, it might act as a marker of cellular damage by this species in vivo.
Neurodegenerative Disease Research Centre, University of London King's College, U.K. J.Spencer@kcl.ac.uk
J P
JP
Spencer
J
J
Wong
A
A
Jenner
O I
OI
Aruoma
C E
CE
Cross
B
B
Halliwell
D000818:Animals; D002417:Cattle; D004247:DNA / Q000187:drug effects* / Q000302:isolation & purification; D004249:DNA Damage; D004791:Enzyme Inhibitors / Q000633:toxicity; D004817:Epidermis / Q000187:drug effects*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects*; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000633:toxicity; D009566:Nitrates / Q000633:toxicity*; D017354:Point Mutation; D013950:Thymus Gland / Q000737:chemistry / Q000187:drug effects*
D004791:Enzyme Inhibitors; D009566:Nitrates; C039642:peroxynitric acid; C002385:linsidomine; D004247:DNA; D008981:Molsidomine