[Effect of mutations for the ruvABC genes on recombination between direct DNA repairs in Escherichia coli strains carrying extended tandem duplication].
The formation of haploid and diploid segregants was studied in Escherichia coli strains carrying heterozygous tandem duplications deoA deoB::Tn5/deoC deoD in the deoCABD operon region, in the genome of mutants for ruvABC genes. Homologous recombination in duplications of rec+ strains and in recBC sbcB, recQ and recF mutants, including those with blocks of both the RecBCD and RecF pathway, was shown in our previous work to be similar to adaptive mutagenesis: in this case, practically each cell forms a recombinant on a selective medium. In this work, mutants for ruv genes were found to differ in this respect, forming segregants at a frequency that was decreased by several orders of magnitude. These data confirm the conclusion that the genetic exchange in duplications proceeds through a special pathway of adaptive (or replicative) recombination connected with DNA replication. Upon selection of recombinants under conditions of thymine starvation, recombination cannot also be induced in ruv mutants. The recombinogenic effect of thymine starvation seems to occur at late stages of recombination, which are controlled by ruvABC genes.
Sukhodolets
V V
VV
State Research Institute of Genetics and Selection of Industrial Microorganisms, Moscow, 113545 Russia. sukhodol@genetika.ru
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009876:Operon; D053484:RecQ Helicases; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D020080:Tandem Repeat Sequences
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C061260:RuvB protein, Bacteria; C489340:recF protein, E coli; C069806:ruvC protein, E coli; C066218:recF protein, Bacteria; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; D043211:Exodeoxyribonuclease V; C468322:exodeoxyribonuclease V, E coli; C071059:Holliday junction DNA helicase, E coli; D000251:Adenosine Triphosphatases; C506724:RecQ protein, E coli; D004265:DNA Helicases; D053484:RecQ Helicases