FIG. 4.

Effect of fts mutations on localization of FtsX to potential division sites in filamentous E. coli cells. Strains induced to express GFP-FtsX or FtsX-GFP were grown under nonpermissive conditions until they became filamentous, at which time they were fixed and examined by fluorescence microscopy to visualize GFP. Relevant division mutations are as follows: ftsZ84(Ts) in EC1158 (A), ftsA12(Ts) in EC1152 (B), and zipA1(Ts) in EC1340 (C); and FtsK depletion in EC1295 (D), FtsQ depletion in EC1179 (E), FtsW depletion in EC1159 (F), and FtsI depletion in EC1181 (G). The arrowhead in panel B points to a faint band sometimes observed in ftsA(Ts) filaments. 4′,6′-Diamidino-2-phenylindole staining was done to verify proper nucleoid segregation (data not shown).