Fig 6. overexpression of iniR induces iniBAC transcription.

Overexpression of either M. marinum (IniR_Mm) or M. tuberculosis (IniR_Mtb) iniR in M. smegmatis results in antibiotic-independent induction of the iniBAC promoter on the reporter plasmid (pRep). M. smegmatis containing the iniBAC reporter plasmid and the ATc inducible iniR_Mm (M. marinum gene MMAR_0612) (A) or iniR_Mtb (M. tuberculosis gene Rv0339c) (C). The presence of the iniR-containing plasmid is indicated with piniR. We compared presence of both plasmids and ATc (in red) to culturing without ATc (in black). We also checked influence of the presence (+) of EMB alone (in blue) and in the presence of both ATc and EMB (in green). M. smegmatis containing only the reporter plasmid and cultured with ATc was used as a control (in grey). (B) and (D) are quantifications of (A) and (C), including day 1 data. The presence (+) or absence (-) of plasmids or EMB/ATc is indicated. The experiment was performed in triplicate. The error bars indicate the s.d. values. The MFI is the mean fluorescence intensity of 30.000 gated cells (The gating strategy shown in Fig 4A was used). Fluorescence intensity (a.u.) of mEos3.1 is depicted on the X-axis for panels (A) and (C).