title: [Possible mechanisms of the origination of chromosomal restructurings. III. The role of chromosome association and isolation].
abstract: The kinetics of early appearance of chromosome breaks and exchanges (5-60 min after ionizing irradiation) in pea roots, in primary culture of embryonal fibroblasts of BALB mice and in chinese hamster cells BIId-ii-FAF-28 has been studied. It was found that chromosome resistance to irradiation increases during mitosis as fast as the process of chromosome isolation is advanced (the latter prevents the interchromosome and interchromatid contacts). From the outset of activation of sister chromatids isolation (i.e. from the end of prophase in pea and mouse cells, and from the beginning of prophase in hamster cells), the chromosomes "cease" to respond to irradiation. The prolongation of the period of isolation of sister chromatids in mouse cells by means of colchicine results in prolongation of the "insensitivity" period. A causal relationship between the chromosome isolation phenomenon and the increase in their radiosensitivity is supposed to exist. The importance of chromosome association and isolation in formation of chromosome breaks and exchanges is discussed.
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D006224:Cricetinae; D003412:Cricetulus; D007887:Fabaceae / Q000235:genetics; D005347:Fibroblasts / Q000528:radiation effects / Q000648:ultrastructure; D005720:Gamma Rays; D051379:Mice; D008807:Mice, Inbred BALB C; D008938:Mitosis / Q000528:radiation effects; D009154:Mutation; D010946:Plants, Medicinal
vernacular_title: Vozmozhnye mekhanizmy vozniknoveniiia perestroek khromosom. Soobshchenie III. Rol' assotsiatsii i obosobleniia khromosom.