The effect of deletions of hns and hha regulators on rtsA, hilC, and hilD transcription. (A) The expression of chromosomal reporters was examined for the following strains (ATCC 14028 background): the wild-type (WT) rtsA-lac strain (JS324), the hha rtsA-lac mutant (IO949), the hns rtsA-lac mutant (IO954), the hha hns rtsA-lac mutant (IO955), the WT hilC-lac strain (JS487), the hha hilC-lac mutant (IO969), the hns hilC-lac mutant (IO971), the hha hns hilC-lac mutant (IO973), the WT hilD-lac strain (JS488), the hha hilD-lac mutant (IO959), the hns hilD-lac mutant (IO961), and the hha hns hilD-lac mutant (IO963). The level of β-galactosidase was determined following growth in LB medium with 1% NaCl (+NaCl) or no added NaCl (−NaCl). Data are representative of three independent experiments. (B) The transcription of the rtsA and marA genes on the chromosome was monitored by RT-PCR following the growth of the WT (IO908) and the hha hns mutant (IO923) in LB medium without NaCl. The experiment was performed three times, and typical data are shown.