title: ["Killer" plasmid mutants obtained by exposure to 5-fluorouracil].
abstract: Weak killers were tolerated from a killer strain of type k2 of Saccharomyces cerevisiae by treatment with 5-fluorouracil. They segregated sensitive clones during vegetative growth with a frequency from 2 to 20 per cent (nonstable killers, Knst mutants). Alteration of killer activity in these mutants is the result of a mutation in the cytoplasmic killer determinant (KIL-k). The mutant form of this determinant, KIL-nst, partially suppresses the wild type determinant. K-nst have the same dsRNA composition as the wild type killer strain. In some mutants the decrease in M dsRNA amount is possible. The segregation of sensitive mitotic clones of these mutants is probably connected with secondary alterations of the KIL-nst determinant.
mesh_terms: D005472:Fluorouracil / Q000494:pharmacology*; D009154:Mutation; D010957:Plasmids / Q000187:drug effects*; D012330:RNA, Double-Stranded / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000032:analysis / Q000187:drug effects / Q000235:genetics*; D014118:Toxins, Biological / Q000235:genetics*
chemical_list: D012330:RNA, Double-Stranded; D014118:Toxins, Biological; D005472:Fluorouracil
vernacular_title: Issledovanie mutantov plazmidy "killer", poluchennykh pod vozdeĭstviem 5-ftoruratsila.