FtsA–GFP localization. (A–E) Cells with pAG and extra copies of lacIq, from colonies on plates without IPTG. (A) JM109/pAG cells with FtsA–GFP fluorescence localized to cell midpoints. Arrows point to double bands. (B) MC1061/pAG cells, with lacIq cloned into the plasmid. (C) Deconvolution image of JM109/pAG cells, one showing FtsA–GFP localization to a midcell ring, the other showing spiral structures. (D) Same cells as in C, at a different angle. (E) Deconvolution image of JM109/pAG cell showing midcell fluorescence and spiral structures. (F) Filamentous JM109/pAG cells with no extra copies of lacIq; higher levels of FtsA–GFP cause bulges and more diffuse fluorescence. (G) Filamentous JM105/pAG/pMK4 cell expressing FtsA–GFP and wild-type FtsZ, with IPTG. (Bars: A, B, F, and G, 5 μm; C and D, 1 μm.)