Correction: Novel recA-Independent Horizontal Gene Transfer in Escherichia coli K-12.

There is an error in Fig 4A. Please see the corrected Fig 4 here.

Fig 4

YjiP promotes recA-independent recombination and reduces cell viability.

(A) The frequency of recombination during matings between the ΔrepE* ΔrecA donor and either the ΔrecA recipient (cross 6; ΔrecA) or a ΔrecA recipient with inducible overexpression of yjiP (cross 13; ΔrecA rhaBp-yjiPc), with and without 0.2% rhamnose. Recombination efficiency was calculated as the frequency of recombinant formation per viable recipient per hour in the mating mixture. Inducing yjiPc expression with rhamnose significantly increases recombination efficiency ~5 fold (P-value = 0.018), but rhamnose has no significant effect when the recipient lacks the rhaBp-yjiPc gene fusion. (B) Cell viability over time of the ΔrecA rhaBp-yjiPcrecipient (ER3460) grown in 0.2% rhamnose. This experiment was performed three times with biological replicates, but only the results of a single representative trial are shown for clarity. Rhamnose was added at t = 0, and cells were mated after 3 hours of growth with ER3435. Untreated and unmated cells were also included as controls. Rhamnose-inducedyjiPc expression reduces cell proliferation for the first three hours after treatment and begins to kill cells afterwards. Mating did not significantly affect cell viability. (C) Dose-response of cell killing: fraction starting titer for three strains at 18 hours as a function of inducer concentration. Strains were ΔrecA (ER3473), recA + rhaBp-yjiPc (ER3480), and ΔrecA rhaBp-yjiPc (ER3460) grown in various concentrations of rhamnose for 18 hours relative to an untreated control. Higher concentrations of rhamnose are increasingly lethal to ER3460; 0.2% rhamnose kills ~90% of the normally viable cells. All experiments in panels A and C were performed with a minimum of three biological replicates with error bars representing standard error.