title: Deoxyribonucleic acid-protein and deoxyribonucleic acid interstrand cross-links induced in isolated chromatin by hydrogen peroxide and ferrous ethylenediaminetetraacetate chelates.
abstract: DNA-protein and DNA interstrand cross-links were induced in isolated chromatin after treatment with H2O2 and ferrous ethylenediaminetetraacetate (EDTA). Retention of DNA on membrane filters after heating of chromatin in a dissociating solvent indicated the presence of a stable linkage between DNA and protein. Treatment of protein-free DNA with H2O2/Fe2+-EDTA did not result in enhanced filter retention. Incubation of cross-linked chromatin with proteinase K completely eliminated filter retention. Resistance to S1 nuclease after a denaturation-renaturation cycle was used to detect DNA interstrand cross-links. Heating the treated chromatin at 45 degrees C for 16 h and NaBH4 reduction enhanced the extent of interstrand cross-linking. The following data are consistent with, but do not totally prove, the hypothesis that cross-links are induced by hydroxyl radicals generated in Fenton-type reactions: (1) cross-linking was inhibited by hydroxyl radical scavengers; (2) the degree of inhibition of DNA interstrand cross-links correlated very closely with the rate constants of the scavengers for reaction with hydroxyl radicals; (3) cross-linking was eliminated or greatly reduced by catalase; (4) the extent of cross-linking was directly related to the concentration of Fe2+-EDTA. Partial inhibition of cross-linking by superoxide dismutase indicates that superoxide-driven Fenton chemistry is involved. The data indicate that DNA cross-linking may play a role in the manifestation of the biological activity of agents or systems that generate reactive hydroxyl radicals.
mesh_terms: D002460:Cell Line; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002843:Chromatin; D003432:Cross-Linking Reagents; D004247:DNA; D004492:Edetic Acid; D004720:Endonucleases; D005290:Ferric Compounds; D005347:Fibroblasts; D005609:Free Radicals; D006861:Hydrogen Peroxide; D007501:Iron; D007502:Iron Chelating Agents; D015719:Single-Strand Specific DNA and RNA Endonucleases; D013482:Superoxide Dismutase
chemical_list: D002843:Chromatin; D003432:Cross-Linking Reagents; D005290:Ferric Compounds; D005609:Free Radicals; D007502:Iron Chelating Agents; D004247:DNA; D004492:Edetic Acid; D006861:Hydrogen Peroxide; D007501:Iron; D013482:Superoxide Dismutase; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases; C019179:Fe(III)-EDTA