Fig. 4.

Hyperactive ftsB and ftsL mutations, but not hyperactive ftsA mutations, confer resistance to overexpressed FtsE^D162NX. (A) Hyperactive ftsB and ftsL mutations confer resistance to overexpressed FtsE^D162NX. Plasmid pSD221 and its variant pSD221-D162N were transformed into strains TB28, BL167 (TB28, ftsB^E56A), BL140 (TB28, ftsB^D59H), MT10 (TB28, ftsL^E88K), and BL154 (TB28, ftsL^D93G). A single transformant of each strain from LB + 0.2 M sucrose plates was then resuspended in 1 mL of LB medium and serially diluted. Three microliters of each aliquot was then spotted on the LB plates or the LB + 0.2 M sucrose plates with appropriate antibiotics and increasing concentrations of IPTG. The plates were incubated at 30 °C overnight before photography and only results from LB plates are shown. (B) Hyperactive ftsA mutations do not confer resistance to overexpressed FtsE^D162NX. Plasmid pSD221-D162N was transformed into strain S3 and its derivatives carrying hyperactive ftsA mutations. A spot test was performed as in A. (C) Diagram indicating the location of hyperactive mutations and the response to FtsE^D162NX. The hyperactive mutations are indicated by the green symbol and are in FtsA or FtsL/FtsB.