<p><b>A.</b><i>sigH</i>-FLAG expression was induced in <i>M</i>. <i>tuberculosis</i> H37Rv (wild type) containing a vector expressing <i>sigH</i>-FLAG under control of a TetR-regulated promoter. Samples were obtained at serial time points following addition of aTc to a final concentration of 200 ng/ml, protein was extracted and Western blotting was performed with an anti-FLAG antibody (Sigma-Aldrich). <b>B</b>. <i>M</i>. <i>tuberculosis</i> H37Rv (wild type) or the Δ<i>sigH</i> strain were exposed to 52°C for 15 minutes. The same strains containing a vector expressing <i>sigH</i>-FLAG under control of a TetR-regulated promoter were induced by addition aTc to a final concentration of of 200 ng/ml (aTc). RNA was extracted after 24h and qRT-PCR was performed and analyzed as described in the Materials and Methods. The higher level of induced <i>sigH</i> expression in wild type compared to the Δ<i>sigH</i> strain likely results from increased expression in wild type of the native copy of <i>sigH</i> from its SigH-regulated promoter following induction of the TetR-regulated copy of <i>sigH</i>.</p
