Figure 5.

TetR-controlled regulation of ftsZ expression in M.smegmatis. (A) Strategy for construction of the conditional ftsZ knockout. A suicide plasmid was used to replace the ftsZ upstream region with P_myc1tetO in an M.smegmatis strain that had P_smyctetR integrated in the attB site. (B) Impact of ftsZ silencing on growth of M.smegmatis. Wt M.smegmatis and the conditional ftsZ knockout were grown in the presence of 40 ng/ml ATc into the mid log phase. The cultures were washed and diluted to an OD₅₈₀ of 0.02 into fresh medium without and with different concentrations of ATc (t = 0). Growth in the presence and absence of ATc was followed by measuring optical densities of the cultures. (C) Photographs of wt M.smegmatis and the conditional ftsZ knockout cultures 20 h after growth without and with 40 ng/ml ATc.