title: On the role of Ca, Mg-dependent nuclease in the postirradiation degradation of chromatin in lymphoid tissues.
abstract: The characteristics of the postirradiation degradation of chromatin in thymocytes in vivo were compared with the features of chromatin fragmentation in isolated thymocyte nuclei in vitro by endogenous chromatin-bound nucleases. Nuclease which degrades chromatin produces in vivo fragments of nucleosomal size; the double-strand breaks appear as the result of the accumulation of single-strand breaks with 3'-OH ends; the nuclease is inhibited by Zn2+ and DTNB and its activity is depressed by cycloheximide pretreatment. In experiments on in vitro degradation of chromatin in isolated thymocyte nuclei similar properties were observed for the Ca, Mg-dependent, but not for acid nuclease. The results bring further evidence of the involvement of an enzyme of the Ca, Mg-dependent nuclease-type in chromatin degradation in irradiated thymocytes.
authors: Institute of Biological Physics, Academy of Sciences of the USSR, Pushchino Moscow Region .
authors: I P
authors: IP
authors: Beletsky
authors: J
authors: J
authors: Matyásová
authors: L V
authors: LV
authors: Nikonova
authors: M
authors: M
authors: Skalka
authors: S R
authors: SR
authors: Umansky
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology / Q000528:radiation effects; D002478:Cells, Cultured; D002843:Chromatin / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects*; D003037:Cobalt Radioisotopes; D003513:Cycloheximide / Q000494:pharmacology; D004247:DNA / Q000302:isolation & purification / Q000528:radiation effects; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D005260:Female; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009691:Nucleic Acid Denaturation; D051381:Rats; D011919:Rats, Inbred Strains; D013601:T-Lymphocytes / Q000201:enzymology / Q000528:radiation effects; D013950:Thymus Gland / Q000201:enzymology / Q000528:radiation effects*; D015032:Zinc / Q000494:pharmacology
chemical_list: D002843:Chromatin; D003037:Cobalt Radioisotopes; D004247:DNA; D003513:Cycloheximide; D004228:Dithionitrobenzoic Acid; D004706:Endodeoxyribonucleases; C029367:calcium magnesium dependent endodeoxyribonuclease; D015032:Zinc