FIG 4.

FleQ is the effector that responds to intracellular c-di-GMP and modulates the activity of H1-T6SS. (A) Relative expression of tse1 measured by RT-qPCR in the indicated PAO1 strains. (B) Western blot analysis of Tse1-His in the cell-associated protein fractions from the indicated PAO1 strains. (C) Bacterial killing assay between the indicated PAO1 strains and the E. coli prey. (D) Prediction of FleQ binding sites in the promoters of the gene cluster tssA1B1C1 and the effector gene tse1 by searching for the FleQ consensus sites (in blue and in red). Data are represented as the mean ± SD (n = 3). ***, P < 0.001 versus PAO1(EV) based on one-way ANOVA. n.s., not significant. EV, empty vector for the control.