title: [Composite transposons Tn5 and Tn10 in Escherichia coli K12: precise excision and recombination].
abstract: The number of exconjugants having the transposon Tn5 excised precisely during the crosses of the Escherichia coli proA::Tn5 donor with the recipients F- rec+ or F- recA441 (tif) was 20-30 times higher for the crosses involving the latter recipient. The high recombinogenic activity is characteristic of the tif recipient. Precise excision from a tandem duplication is more efficient than from nonduplicated region of the genome. It is four orders higher, if a transposon is localized in an arm of a duplication. The effect is recA-dependent. The presented data permit us to suggest the participation of RecA protein (its synaptic function) in the formation of the intermediate "stem-loop" structure. The latter is predicted by the three mechanisms of transposon excision: "slippage", "correctional" and "recombinational". The latter two mechanisms were formulated in the paper. The experimental proof of the postexcision transposition presented in the paper, is a good support to the version of "recombinational" excision.
mesh_terms: D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D008957:Models, Genetic; D010641:Phenotype
chemical_list: D004251:DNA Transposable Elements
vernacular_title: Sostavnye transpozony Tn5 i Tn10 u Escherichia coli K12: tochnaia ékstsiziia i rekombinatsiia.