title: [Genetic nature of one of the traits of malignant cell transformation in vitro].
abstract: The genetic events controlling the ability of transformed cells to grow in a medium with a low serum content (ser+) were studied. A hypodiploid clone of Chinese hamster cells with normal serum requirements (49a5ser-) was used as starting material. The results of the fluctuation tests have shown that serum-independence is a random spontaneous event. Its rate of occurrence is 1-2 . 10(-5). The concomitant study of a gene mutation (resistance to 6-mercaptopurine) revealed similar characteristics with respect to the distribution of the number of mutants in replicate cultures and the mutation rate. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and the oncogenic SV40 virus significantly increased the frequency of ser+ colonies. In the majority of clones isolated in a medium with 1% serum (11 spontaneous and 7 induced by MNNG), the ser+ character proved to be stable after different periods of cultivation without selective pressure. The degree of serum-independence varied in different clones. The results suggest that the ability to grow in a medium with a low serum content originates, in most cases, from a mutation event.
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D002999:Clone Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006224:Cricetinae; D003412:Cricetulus; D003470:Culture Media / Q000378:metabolism; D004171:Diploidy; D004351:Drug Resistance; D005821:Genetic Techniques; D015122:Mercaptopurine / Q000037:antagonists & inhibitors; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D009154:Mutation; D013539:Simian virus 40 / Q000472:pathogenicity
chemical_list: D003470:Culture Media; D008769:Methylnitronitrosoguanidine; D015122:Mercaptopurine
vernacular_title: Geneticheskaia priroda odnogo iz priznakov zlokachestvennoĭ transformatsii kletok in vitro.