FIG 2.

The gene deletion mutants are defective for cytosolic proliferation but not nascent vacuole lysis. (A) HeLa epithelial cells were infected with wild-type (WT) S. Typhimurium SL1344 and the ΔasmA, ΔcorA, ΔrecA, and ΔydgT gene deletion mutants. The percentage of cytosolic bacteria was quantified by a CHQ resistance assay at 1.5 h and 7 h p.i. Data were obtained from at least three independent experiments (means ± SD). Asterisks indicate data significantly different from those for the wild type. (B) HeLa cells were infected with wild-type strain SL1344 and the gene deletion mutants complemented in trans (ΔcorA-pWSK30-corA, ΔrecA-pWSK29-recA, and ΔydgT-pWSK29-ydgT) or in the chromosome at the attTn7 site (ΔasmA glmS::asmA). ΔcorA, ΔrecA, and ΔydgT mutants harboring an empty pWSK29 or pWKS30 plasmid were also included as controls. The proportion of cytosolic bacteria at 7 h p.i. was determined by the CHQ resistance assay. Means ± SD from at least three independent experiments are shown. Asterisks indicate data significantly different from those for the respective gene deletion mutant.