title: [Activation of the chromatin degradation process by a protein factor from the cytoplasm of the thymocytes of irradiated animals].
abstract: A cytoplasmic thymocyte fraction isolated 1 h after irradiation of mice accelerates chromatin degradation in isolated nuclei. Treatment of the cytoplasmic fraction by heat and injection of cycloheximide to mice prevent the acceleration of DNA degradation. The analysis of the chromatin degradation products and the kinetics of this process at acid and alkaline pH shows that activation of DNA degradation in thymocytes by a factor obtained from the irradiated cell cytoplasm is specific for a Ca2+, Mg2+-dependent enzyme. The time- and dose-dependent parameters of the appearance in the thymocyte cytoplasm of the factor influencing degradation of chromatin are in a good agreement with both the time of the onset of its postirradiation degradation and the dose dependence of this process.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002843:Chromatin / Q000187:drug effects* / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D003593:Cytoplasm / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004706:Endodeoxyribonucleases / Q000378:metabolism / Q000528:radiation effects*; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D005720:Gamma Rays; D007399:Interphase / Q000187:drug effects / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D013950:Thymus Gland / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects*; D013997:Time Factors
chemical_list: D002843:Chromatin; D004247:DNA; D003513:Cycloheximide; D004706:Endodeoxyribonucleases; C029367:calcium magnesium dependent endodeoxyribonuclease
vernacular_title: Aktivatsiia protsessa degradatsii khromatina belkovym faktorom tsitoplazmy timotsitov obluchennykh zhivotnykh.