Genetic Analysis and Regulation of Inducible Recombination in Escherichia coli K-12

Abstract

The highly efficient conjugational process of genetic exchange in Escherichia coli has provided a useful model system for investigating recombination between homologous DNA molecules. In standard Hfr × F− crosses, the formation of viable recombinants normally requires the products of recB and recC, which together specify a DNA dependent ATPase that functions both as a nuclease and as a DNA helicase (Telander Muskavitch and Linn 1981). An alternative, recBC-independent mechanism can be activated in recBC mutants by the additional mutation of sbcB, the structural gene for exonuclease I (Kushner et al. 1971, 1972). This depends on the function of recF, recJ, recN, and ruv products, none of which is essential in the presence of RecBC enzyme (Horii and Clark 1973; Lloyd et al. 1983, 1984; Lovett and Clark 1984).