FIG. 8.

Effects of ysrS on the expression of selected genes involved in Ysa TTS. Genes involved in Ysa type III protein secretion require YsrS for expression. Selected reporter strains and isogenic derivatives are shown. (A) ysaE-lacZYA. (B) orf6 orf7-lacZYA. (C) ysaR-lacZYA. (D) ysaU-lacZYA. (E) rcsB-lacZYA. (F) sycB-lacZYA. For each panel, levels of expression are displayed for different genetic backgrounds: wild type (WT), ysrS (ysrS), plasmid control (ysrS, pTM100), and in trans complementation (ysrS pysrRS⁺). β-Galactosidase activity was determined for each strain cultivated in L medium plus 290 mM NaCl at 26°C. The results are averages ± standard deviations from at least two independent experiments performed in duplicate.