FIG. 3.

FliZ activation of hilA is dependent on HilD. (A) β-Galactosidase activity in strains containing a hilA-lacZ transcriptional fusion and the indicated mutations after growth under SPI1-inducing conditions. (B) β-Galactosidase activity of strains containing a hilA-lacZ transcriptional fusion and indicated mutations with rtsA under the control of a tetracycline-regulated promoter. The strains were grown under SPI1-inducing conditions with the indicated concentrations of tetracycline (Tet). The strains used were JS749 and JS950 to JS956. β-Galactosidase activity units are defined as (μmol of ONP formed per min × 10³)/(OD₆₀₀ × ml of cell suspension) and are reported as means ± standard deviations (n = 4).