FIG 6.

Confirmation of the effect of MbtS on the transcription of staphylococcal genes. (A) qRT-PCR analysis for the genes whose transcription was affected by MbtS in RNA-seq. The experiment was carried out in quintuplicate. The analyzed genes are indicated. (B) Effect of the disruption of mbtS on the promoter activity of P₂₆₄₂. The reporter plasmid pOS1-P₂₆₄₂-lacZ was inserted into the test strains, and then the cells were grown overnight and the LacZ activity was measured with ONPG. The experiment was carried out in triplicate and repeated twice with similar results. (C and D) Effect of disruptions of SAUSA300_2641 and SAUSA300_2642 on P_mbtS activity (C) and MbtS expression level (D). The reporter plasmid pOS1-P_mbtS-lacZ was inserted into the test strains, and the LacZ activity was measured as described above. The proteins were detected by Western blotting. The LacZ assay was carried out in triplicate and repeated twice with similar results. The statistical significance was measured by an unpaired, two-tailed Student t test. **, P < 0.005; ***, P < 0.001; ****, P < 0.0001. WT, wild-type strain USA300; mbtS, USA300 with a transposon insertion in mbtS; ΔftsH, ftsH deletion mutant of USA300; ΔftsH::mbtS; ΔftsH mutant with a transposon insertion in mbtS; 2641, USA300 with a transposon insertion at SAUSA300_2641; 2642, USA300 with a transposon insertion at SAUSA300_2642.