title: [Thiol-induced fragmentation of chromosomal DNA].
abstract: Supramolecular complexes of DNA (SC DNA) were isolated from loach sperm, loach erythrocytes and hen erythrocytes by the phenol method. By the use of UV-sedimentation on neutral 5-20% sucrose gradient, we studied the effect of 2-mercaptoethanol (ME), dithiothreitol (DTT) and NaBH4 on SC DNA at different pH and long-time incubation (5 and 10 days). It appeared that ME treatment at pH 4.4 fragmented SC DNA of three objects into subunits of size 5 x 10(5)D. Incubation with DTT at pH 8 in the presence of EDTA resulted in subunits of size 1-2 x 10(7)D. However, NaBH4 at pH 8 failed to induce fragmentation of SC DNA. It is shown that ME-induced at pH 4.4 fragmentation is accompanied by a decrease in hyperchromatic effect of subunits, indicating the presence of "sticky" ends. Thus, ME-induced fragmentation of SC DNA results from a "clayting" double-strand break, involving, on an average, 180 bp.
authors.forename: V A
authors.initials: VA
authors.lastname: Struchkov
authors.forename: N B
authors.initials: NB
authors.lastname: Strazhevskaia
authors.forename: D Iu
authors.initials: DIu
authors.lastname: Blokhin
mesh_terms: D000818:Animals; D001894:Borohydrides / Q000494:pharmacology; D002645:Chickens; D002875:Chromosomes / Q000187:drug effects*; D004247:DNA / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects; D004249:DNA Damage; D004229:Dithiothreitol / Q000494:pharmacology; D004912:Erythrocytes / Q000648:ultrastructure; D005399:Fishes; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D008623:Mercaptoethanol / Q000494:pharmacology; D009691:Nucleic Acid Denaturation; D013094:Spermatozoa / Q000648:ultrastructure; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D001894:Borohydrides; D013438:Sulfhydryl Compounds; D008623:Mercaptoethanol; C025364:sodium borohydride; D004247:DNA; D004229:Dithiothreitol
vernacular_title: Tiol-indutsirovannaia fragmentatsiia khromosomal'noĭ DNK.