LsrR is involved in the regulation of SPI-1 expression and invasion of <i>S. typhimurium</i>.

<p>(A) Wild-type (WT) and mutant strains carrying a chromosomal <i>invF-lacZ</i> fusion were diluted in LB medium and β-galactosidase activity (Miller units) was determined at 4 h of cultures grown with shaking. Values are the means and standard deviation of three independent experiments. (B) Monolayers of HEp-2 epithelial cells were infected with the wild-type (WT) and mutant strains and numbers of internalized bacteria were determined (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037059#s4" target="_blank">Methods</a>). Values represent the relative amount of internalized bacteria normalized to the level of internalization of the WT strain, which was set to 1.00. Values are the average and standard deviation from three independent experiments, each done in triplicate.