title: [The genetic Rec system of homologous recombination in Escherichia coli].
abstract: A review of modern data on genetic and biochemical bases of the Rec system is presented. Taking into consideration the final result of recombination, that is the preferential way of integration of donor DNA into recipient chromosome, it is proposed to distinguish three main pathways of homologous recombination RecBC (recF- recipient genotype), RecF (recBC- sbcB- sbcC-) and SOS. A recBC nuclease unwinds a donor linear DNA duplex to create the 3'-single-stranded end which was shown to be responsible for the initiation of recombination with the help of RecA protein. As a result, integration of single- and double-stranded donor fragments into recipient chromosome takes place in full accordance with the Meselson-Radding model. The peculiarity of the RecF pathway is its ability to promote recombination between two DNA closed ring structures. The SOS way is characterized by frequent single-stranded DNA exchanges. Both pathways are interconnected. The SOS way is regarded here as an extreme situation of the RecF one.
mesh_terms: D004926:Escherichia coli / Q000235:genetics*; D011938:Rec A Recombinases / Q000235:genetics*; D011995:Recombination, Genetic
chemical_list: D011938:Rec A Recombinases
vernacular_title: Geneticheskaia sistema Rec gomologicheskoĭ rekombinatsii u Escherichia coli.