FIG 1.
Specific pe and ppe genes are regulated by Pst/SenX3-RegX3. (A) RNA was extracted from cultures of M. tuberculosis WT, ΔpstA1, ΔregX3, ΔpstA1ΔregX3, ΔregX3 pNDregX3, and ΔpstA1ΔregX3 pNDregX3 strains grown to mid-exponential phase (OD600 of 0.5) in Pi-rich 7H9 medium. The abundance of ppe25, pe19, and ppe65 transcripts relative to that of sigA was determined by real-time quantitative RT-PCR. Data shown are the means ± standard deviations from three independent experiments. Asterisks indicate statistically significant differences from the WT: *, P < 0.05; **, P < 0.001. (B) RNA was extracted from cultures of M. tuberculosis WT, ΔregX3, and ΔregX3 pNDregX3 strains at the indicated times after shifting to Pi-free 7H9 medium. pe19 transcript abundance relative to that of 16S rRNA was determined by real-time quantitative RT-PCR. Data shown are the means ± standard deviations from three independent experiments. Asterisks indicate statistically significant differences from both the respective 0-h time point and the ΔregX3 mutant: *, P < 0.005; **, P < 0.0005.