Identification of additional cytosol-induced S. Typhimurium genes.

Upper panels: Epithelial cells were infected with mCherry-S. Typhimurium harboring gfpmut3 transcriptional reporters. At 8 h p.i., cells were fixed & stained with Hoechst 33342 to detect DNA. Representative confocal microscopy images show induction of cysP, grxA, soxS, sfbA, fruB and uhpT promoters in cytosolic bacteria. Green = transcriptional reporter, red = S. Typhimurium, blue = DNA. Scale bars are 10 μm. Lower panel: Quantification of the MFI of GFP signal by fluorescence microscopy and ImageJ. Small dots represent individual bacteria; large dots indicate the mean of each experiment; horizontal bars indicate the average of 2–3 experiments. Acquisition parameters (exposure time and gain) were set-up using PcysP-gfpmut3 (the highest GFP signal intensity) and these same parameters were applied throughout. Dashed lines indicate the range of background fluorescence in the GFP channel measured for mCherry-S. Typhimurium (no reporter).

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