Figure 2.
PAAR proteins are required for full functionality of the T6SS in Vibrio cholerae and Acinetobacter baylyi. a, Recovery of viable E. coli MG1655 after co-incubation with A. baylyi ADP1 (WT) and its T6SS and PAAR genes knockout mutants. The following genes were inactivated in the mutants shown: T6S¯ – aciad2688 to aciad2694; 2681¯ – aciad2681; 0051-52¯ – both aciad0051 and aciad0052; 3×P¯ – all three PAAR genes aciad0051, aciad0052 and aciad2681. Right subpanel: Leaky, basal expression of the aciad2681 PAAR gene from plasmid pMMB67EH26, labeled as p2681, restores the killing defect in the triple PAAR mutant. b, Recovery of E. coli MG1655 colony forming units after co-incubation with V. cholerae 2740-80 and its T6SS and PAAR genes knockout mutants, which are labeled as follows: T6S¯ – vipA; 105¯ – vca0105; 284¯ – vca0284; 2×P¯ – vca0105 and vca0284. Symbols *, **, and *** indicate deviations from the WT with p-values of 6×10−3, 8×10−3, and 5×10−7, respectively, for a sample size of 8. Error bars represent one standard deviation. c, SDS-PAGE assay for T6SS-dependent secretion of Hcp proteins by the parental strains and T6SS and PAAR genes knockout mutants. Panels a and c show one out of three experiments with similar outcomes.