Co-transduction with serB of a pleiotropic mutation affecting colicin E2 refractivity, ultraviolet sensitivity, recombination proficiency and surface properties of Escherichia coli K12.

Abstract

SUMMARY: A cetE locus, determining E2 refractivity at low temperature, has been mapped at minute 89 on the Escherichia coli K12 chromosome and is 94% linked to the hsp loci. A second locus, cetA, which controls expression of cetB in some way, was found to be 70% co-transducible with and to the right of thr. Both cetB and cetC, another locus which determines E2 refractivity, are 21% co-transducible with serB and the cetC locus therefore also probably lies close to hsp. Mutations of the cetC locus appear to be pleiotropic and the additional characteristics of these mutants, u.v. sensitivity, detergent sensitivity, recombination deficiency, filament formation, and abortive λ growth, are all fully co-transducible with E2-refractivity. In addition, u.v.-resistant revertants of CetC mutants simultaneously revert to all wild-type characteristics including E2 sensitivity. The nature of the recombination deficiency of some CetC mutants has been examined and both episomal and chromosomal gene transfer to the mutants found to be normal. P1 transduction frequencies with CetC mutants are, however, also normal and it is suggested that the mutants may be deficient in some recombination step unique to Hfr x F- crosses.