DNA cleavage in chromatin spacer segments by a non-enzymic probe, 1,10-phenanthroline-copper complex.
The action of 1,10-phenanthroline-copper complex under aerobic conditions in the presence of 2-mercaptoethanol on chromatin DNA in murine thymocyte nuclei was studied. At limited oxygen supply primarily multiple single-strand breaks of DNA in the spacer segments are observed while the core DNA segments in chromatin remain intact. After the single-strand breaks accumulate in both DNA strands (under conditions of improved oxygen supply), double-strand cleavage of DNA to fragments of nucleosomal size becomes apparent. This regular character of DNA degradation in chromatin is apparently due to the preferential binding of the 1,10-phenanthroline-copper complex to DNA of the spacer segments and to the localized generation of damaging radicals.
D000818:Animals; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000187:drug effects / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D051379:Mice; D009707:Nucleosomes / Q000378:metabolism; D010618:Phenanthrolines / Q000378:metabolism / Q000494:pharmacology*; D013950:Thymus Gland / Q000378:metabolism
D002843:Chromatin; D004277:DNA, Single-Stranded; D009707:Nucleosomes; D010618:Phenanthrolines; C014741:bis(1,10-phenanthroline)copper(2+) ion; D004247:DNA