Fig. 2. ClpX overexpression blocks Z-ring assembly.
A. ClpX overexpression increases cell length. Cells encoding both an IPTG-inducible clpX allele and an ftsZts allele (BW243) were grown in LB at 37°C with 10 μM IPTG to maintain basal levels of ClpX expression. At mid-exponential phase (OD600 ~0.400) cultures were back-diluted into LB containing either 10 μM IPTG (grey bars) or 1 mM IPTG (black bars) and grown for ~2.5 h prior. FtsZts (FtsZ– GFP) was visualized in live cells using fluorescence microscopy. Arrows indicate Z rings in cells grown in LB with 10 μM IPTG. Scale bar = 2.5 μm.