Characterization of damage in gamma-irradiated and OsO4-treated DNA using methoxyamine.
Unlabelled and radiolabelled methoxyamine have been used to characterize DNA damage caused by gamma-rays or by the chemical reagent osmium tetroxide (OsO4). Both treatments introduce in DNA a number of methoxyamine-binding sites proportional to the dose. Whereas the number of these sites remains constant after the OsO4 treatment it increases during postirradiation incubation; the postirradiation appearance of methoxyamine-binding sites is enhanced by the presence of methoxyamine. OsO4 treatment and gamma-irradiation also induce the formation of alkali-labile sites in DNA. Whereas the number of these sites remains constant after OsO4 treatment, it increases during postirradiation incubation and an alkaline medium accelerates their formation. A fraction of the alkali-labile sites found in gamma-irradiated DNA is methoxyamine-labile; by contrast, the OsO4-treated DNA is stable in the presence of methoxyamine.
D004249:DNA Damage; D004269:DNA, Bacterial / Q000187:drug effects / Q000528:radiation effects*; D004926:Escherichia coli / Q000235:genetics; D005720:Gamma Rays; D006898:Hydroxylamines; D007202:Indicators and Reagents; D009992:Osmium / Q000494:pharmacology*; D009993:Osmium Tetroxide / Q000494:pharmacology*
D004269:DNA, Bacterial; D006898:Hydroxylamines; D007202:Indicators and Reagents; D009992:Osmium; C005214:methoxyamine; D009993:Osmium Tetroxide