[Increased frequency of unequal crossing over in recBC mutant cells in conjugational crosses in Escherichia coli K-12].
The formation of heterozygous tandem duplications was studied in conjugational crosses of Escherichia coli using mutations for deo-operon genes. The frequency of tandem duplications in recF::Tn3 and recBC sbcB mutants was not substantially changed from that of the wild type strain. In contrast, the frequency of duplications was increased about ten-fold when using recBC (sbcB+) mutants as recipients. This result can be explained by a participation of the RecBCD protein in the pairing of chromosomes during recombination. We also found that HfrH thyA recBC (sbcB+) bacteria grow very poorly on rich medium and that good growth is restored by conversion from the Hfr to the F+ state, as well as by mutations suppressing the RecBC phenotype; such F+ strains retain sensitivity to UV light and to mitomycin C, which are characteristic of the recBC phenotype.
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D003227:Conjugation, Genetic; D003434:Crossing Over, Genetic; D004926:Escherichia coli / Q000235:genetics*; D005819:Genetic Markers; D006579:Heterozygote; D005810:Multigene Family; D009154:Mutation; D009876:Operon
D005819:Genetic Markers
Povyshenie chastoty neravnogo krossingovera v kletkakh mutantov recBC v kon"iugatsionnykh skreshchivaniiakh u Escherichia coli K-12.