FIG. 5.

E. coli septal targeting of DivIC_flag3/FtsL_Bflag3 complex, tested in the absence of ZapA, fused to one of them or tested in an FtsQ depletion strain. (A) Fluorescence microscopy images showing subcellular localization of DivIC_flag3 and FtsL_Bflag3 GFP fusions when coexpressed with DivIC_flag3, FtsL_Bflag3, ZapA-DivIC_flag3, or ZapA-FtsL_Bflag3 or in cells carrying an empty plasmid. Strains CR275 (a), CR278 (b), CR211 (c), CR279 (d), CR280 (e), and CR213 (f) were grown at 30°C, and tested proteins were induced for 30 min with 20 μM IPTG. Samples were then prepared for microscopy as described in Materials and Methods. (B) Subcellular localization of GFP-DivIC_fllag3 and GFP-FtsL_Bflag3 when coexpressed with ZapA-FtsL_Bflag3 (a) and ZapA-DivIC_flag3 (b), respectively, or with ZapA-FtsB as a negative control (c) in an E. coli ftsQ-depleted strain. Strains CR253, CR257, and CR251 were depleted of FtsQ and complemented by the wild-type ftsQ gene carried on a pBAD plasmid and repressed in the presence of glucose. Cells expressed the GFP fusion from a pDSW204 plasmid, integrated on the chromosome, and ZapA fusions on a plasmid, after induction with 20 μM IPTG during 30 min at 30°C. Samples were prepared for microscopy as described in Materials and Methods, and phase-contrast and fluorescence microscopy images are shown for each strain. Arrows indicate some septal localizations in filaments.