Fig 2. Isolation of dominant-negative FtsW mutants.

(A) Wrinkled-colony-based screen for dominant-negative FtsW mutants. A plasmid library harboring mutagenized ftsW expressed from an IPTG-inducible promoter was transformed into strain JS238 and transformants selected on LB plates with ampicillin and 30 μM IPTG. Most colonies were rounded and smooth, but a small percentage of colonies displayed a flat and wrinkled morphology. Inspection of the two types of colonies revealed that the wrinkled colonies consisted of chaining and filamentous cells. Scale bar, 3 μm (B) Toxicity of dominant-negative FtsW mutants. Plasmids harboring the indicated alleles of ftsW were transformed into JS238 and transformants selected on LB plates with ampicillin and glucose. The spot test was performed as in Fig 1A. (C) Location of dominant-negative ftsW mutations in a topology model of FtsW. These mutations, indicated by a magenta heptagon, were clustered in ECL2, ECL3, ECL4 and ECL5 of FtsW.