Figure 1.—
(A) Copy number of ileS gene and levels of mRNA ileS in wild-type (WT), mupirocin-resistant (R1, R2, and R3), and compensated strains (C1–C12). The amino acid substitutions in IleRS that confer mupirocin resistance are indicated under the x-axis (H594Y, F596L, and WV631L). Wild-type level was set to 1.0. (B) Improvement of fitness as a function of the relative level of ileS expression. Fitness corresponds to the relative growth rate measured in LB (solid circles) and LB containing 100 μg/ml of mupirocin (open circles). Wild-type fitness in LB was set to 1.0 and the relative fitness of the strains was calculated as the ratio of tgen(wt)/tgen(mutant).