[Nature of breaks inducible in DNA at the early stages of interphase cell death].
Dynamics of changes in 3'-OH- and 5'-OH-ends of DNA was determined by "nick"-translation and direct polynucleotide kinase reaction, respectively, in animal thymocytes after irradiation and administration of hydrocortisone. Breaks bearing both 3'-OH- and 5'-OH-ends were found in DNA after irradiation. In 40 min repair of single-strand breaks was almost completed, and enzymatic breaks were accumulated with 3'-OH-ends only. 60 min after the administration of hydrocortisone, the number of nuclear DNA breaks containing 3'-OH-ends, but not 5'-OH-ends, sharply increased. Upon DNA autolysis in isolated nuclei acid nuclease produced 5'-OH-ends, and Ca2+/Mg2+-dependent nuclease, 3'-OH-ends. No activity of Mg2+-dependent nuclease was registered either in the nuclei of control thymocytes or in the nuclei isolated from thymocytes of exposed rats.
D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004247:DNA / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D004249:DNA Damage; D004720:Endonucleases / Q000378:metabolism; D006854:Hydrocortisone / Q000494:pharmacology; D007399:Interphase / Q000187:drug effects / Q000528:radiation effects*; D008297:Male; D051379:Mice; D009690:Nucleic Acid Conformation / Q000528:radiation effects; D051381:Rats; D011919:Rats, Inbred Strains; D013950:Thymus Gland / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D013997:Time Factors
D004247:DNA; D004720:Endonucleases; D006854:Hydrocortisone
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