General Recombination in Escherichia coli K-12: In Vivo Role of RecBC Enzyme

Heterozygous lacZ- merodiploids of Escherichia coli K-12 have been used to study the role of the RecBC enzyme in general recombination. The transcribable intermediate assay detects the product of early steps in recombination without requiring the formation of viable recombinant colonies. Recombination is initiated by infection with A precA+. We have found that transcribable intermediate formation in crosses between F42 lac and chromosomal lac is dependent on F fertility functions and an active RecBC enzyme. Thus, the products of of the F42 lac donor DNA by conjugation immediately after infection with A precA+ abolishes the requirement for an active RecBC enzyme. The function of the RecBC enzyme, also known as exonu-clease V, in general recombination in Escherichia coli K-1