Fig 4.
Sensitivity of yvcL mutants for altered FtsZ levels. (A) yvcL mutant is sensitive to reduced cellular FtsZ levels. Serial dilutions of ΔyvcL and ΔzapA mutant strains containing an IPTG-inducible ftsZ gene (KS268, Pspac-ftsZ; KS162, ΔzapA Pspac-ftsZ; and KS748, ΔyvcL Pspac-ftsZ). Dilutions were spotted onto plates with 30 or 500 μM IPTG. (B) FtsZ overexpression restores growth and cell division of a yvcL zapA double mutant. FtsZ overexpression was accomplished by the introduction of an ectopic Pxyl-driven ftsZ copy. Serial dilutions of strains PG8 (Pxyl-ftsZ), PG735 (ΔzapA Pxyl-ftsZ), KS737 (ΔyvcL Pxyl-ftsZ), and PG738 (ΔzapA ΔyvcL Pxyl-ftsZ) were spotted onto plates with 0, 0.025, 0.05, and 0.075% xylose. (C) Phase-contrast images of strain PG738 (ΔzapA ΔyvcL Pxyl-ftsZ) grown in the absence or presence of 0.025% xylose, indicating that overexpression of FtsZ restores cell division. Scale bar, 5 μm.