Production of DNA Strand Breaks by the Hydroxyl Radical

Achey, Phillip M.; Duryea, H. Z.

doi:10.1080/09553007414550791

Cited by 32 publications

(9 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Oxygen appears to terminate the nucleic acid and histone radicals prematurely, preventing the formation ofhydroxyl radicalinduced crosslinks. Similar radical efficiencies have been reported for DNA strand breakage (20)(21)(22) and for the inactivation of DNA as measured by its ability to produce phage particles (23). That the hydroxyl radical may play a major role in radiationinduced damage in cultured mammalian cells has been demonstrated by irradiation of cells in the presence of radical scavengers (3,20).…”

Section: Discussionsupporting

confidence: 58%

Predominance of core histones in formation of DNA--protein crosslinks in gamma-irradiated chromatin.

Mee¹,

Adelstein²

1981

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Chromatin and a subunit ofchromatin containing a complex of DNA and the core histones-H2A, H2B, H3, and H4-have been prepared from cultured Chinese hamster cells.Comparison of the formation of radiation-induced DNA-protein crosslinks in whole chromatin with that in the DNA-core histone complex has demonstrated that the core histones are the specific proteins involved in crosslinking. y irradiation of the chromatin subunit in the presence of radical scavengers has shown the hydroxyl radical to be the most effective aqueous radical intermediate for the promotion of crosslinking and the solvated electron and superoxide radical to be essentially ineffective.DNA-protein crosslinks are formed when whole cells or mixtures of DNA and cell protein in vitro are subjected to y or UV irradiation (1,2 It is generally accepted that, in eukaryotic cells,,nuclear DNA is organized as nucleosomes, consisting of a core region, containing the histon-es H2A, .H2B, H3, and H4, wrapped around with DNA; these core regions are joined by-linker DNA, probably. associated with H1 histone. Isolated together with the 'DNA and histones in purified chromatin are nonhistone chromosomal proteins (NHCP), probably consisting of as many as 100 structural, enzymic, and regulatory proteins, of which 15-20 are major constituents.Chromatin and a subunit of chromatin containing a complex of DNA and the core histones have been isolated from cultured Chinese hamster cells. On the basis ofcomparing radiation-induced crosslinking in the whole chromatin and in the chromatin subunit, we have now identified the core histones as the specific chromosomal proteins predominantly involved in crosslinking to DNA. Furthermore, y irradiation of the chromatin subunit in the presence of radical scavengers has confirmed the efficacy of the hydroxyl radical for the promotion of formation of crosslinks, and the inefficacy ofthe solvated electron and superoxide radical (3). MATERLALS AND METHODSCell Culture and Labeling. Chinese hamster lung fibroblasts (V79-753 cell line from J. A. Belli, Harvard Medical School) were grown as described (4). Eagle's minimal essential medium was supplemented with 15%.fetal bovine serum, 4% NCTC-109 medium (M. A. Bioproducts, Walkersville, MD), 2 mM L-glutamine, 0.1 mM of each nonessential amino acid, penicillin at 50 units/ml, and streptomycin at 50 Ag/ml. Cells were grown as monolayers in 150-cm2 plastic flasks at 370C in an atmosphere of 5% CO2. They were grown for two generations (18 hr) prior to harvesting in a medium containing [methyl-3H]thymidine (New England Nuclear) at.a concentration of0.25 ,uCi/ml (1 Ci = 3.7 x -101 becquerels) to label the DNA, and in some experiments, in a medium containing L-[U-'4C]lysine (New En-gland Nuclear) at a concentration of 0.5 ,Ci/ml to label the proteins.Preparation of Chromatin and a Chromatin Subunit. The isolation of chromatin from the cell pellet has been described in detail (4). Nuclei were prepared.by the method ofHymer and Kuff (5), in which cells were suspended in hypotonic sucrose b...

show abstract

Section: Discussionsupporting

confidence: 58%

Predominance of core histones in formation of DNA--protein crosslinks in gamma-irradiated chromatin.

Mee¹,

Adelstein²

1981

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…However, only under oxygensaturated conditions do • OH radicals result in single-and double-strand breaks (SSB, DSB), the most important damage to DNA [3,4]. Previous studies showed that SSB are produced by one-hit events of irradiation energy deposition because of a linear dose response over a wide dose range [5,6].…”

Section: Introductionmentioning

confidence: 99%

Formation of single- and double-strand breaks of pBR322 plasmid irradiated in the presence of scavengers

Shao¹,

Saito

Zhang³

1999

Radiation and Environmental Biophysics

View full text Add to dashboard Cite

By the method of gel electrophoresis, radiation-induced DNA single- and double-strand breaks (SSB, DSB) were studied with a model system of pBR322 solution in vitro in the presence of 'OH radical scavengers, mannitol and TE (10(-2) mol dm(-3) Tris and 10(-3) mol dm(-3) ethylene diamine tetra-acetic acid). Experiments showed that SSB resulted from one-hit events of radiation energy deposition and DSB resulted from both one-hit and two-hit energy deposition events and so were distinguished into two classes of alphaDSB and betaDSB. Moreover, alpha/beta, where alpha is the number of DSB per unit dose induced in one irradiation event and beta the number of DSB per unit squared dose induced by the combination of two independent SSB, was related to the scavenging capacity, sigma, and for sigma > 10(8) s(-1), alphaDSB predominate over DSB. On the other hand, if sigma<2x10(8)s(-1), the measured G(alphaDSB) decreased in parallel with G(SSB), i.e., G(alphaDSB)/G(SSB) was a constant. When sigma>2x10(8) s(-1). G(alphaDSB) decreased slightly so that the ratio of alphaDSB to SSB evidently increased. Therefore, alphaDSB could be induced by the radical transfer mechanism for sigma<2x10(8) s(-1) and contrarily produced by the local multiply damaged sites (LMDS) mechanism for sigma larger than this value. In addition, the distance for two independent complementary SSB forming a DSB was deduced, but no apparent variation of it was found in the wide sigma range from approximately 10(5) to approximately 10(9) s(-)1, which shows that the DNA steric structure was not influenced by mannitol.

show abstract

“…For low molecular weight DNA melting starts at lower temperature (Crothers et al, 1965) as shown by the values of T~ in Tables 1-2. Lowering of Tm observed suggest the lowering of molecular weight of DNA as a result of strand breaks induced by 7-irradiation (Achey and Duryea, 1974). Fall in Tm with v-dose also shows some dependence on the concentration of DNA present.…”

Section: Shift Of X and Y-peaksmentioning

confidence: 68%

Dependence of?-irradiated Y-peak and melting of DNA on concentration and ionic environment

Attri

Mookerjee

1981

Radiat Environ Biophys

View full text Add to dashboard Cite

Y-peak is found to be a function of ionic strength and concentrations of DNA. The Y-peak reveals close dynamic interaction between DNA and solvent system. Electronic transitions responsible for Y-peak are not the same transitions that are responsible for X-peak. Y-peak's electronic transitions are indicative of charge transfer complex formation between DNA and solvent system. gamma-Irradiation induces hyperchromicity due to strand separation at lower doses. A-T base pairs are first to undergo coiled state as shown by delta Tm spread. Strand chopping and saturation of double bonds of the exposed bases by free radicals (H degrees and OH degrees) give rise to hypochromic regions at X-peak. Rise in ionic strength and the concentration of DNA has protective effect against gamma-damage. Y-peak is found to be a function of solvent, whereas, X-peak is independent of solvent nature.

show abstract

Production of DNA Strand Breaks by the Hydroxyl Radical

Cited by 32 publications

References 8 publications

Predominance of core histones in formation of DNA--protein crosslinks in gamma-irradiated chromatin.

Predominance of core histones in formation of DNA--protein crosslinks in gamma-irradiated chromatin.

Formation of single- and double-strand breaks of pBR322 plasmid irradiated in the presence of scavengers

Dependence of?-irradiated Y-peak and melting of DNA on concentration and ionic environment

Contact Info

Product

Resources

About