Fig. (3) Fur and FitR repressed fit expression independently. A, B), Iron is not required for repression of fit expression by FitR. E. colistrains carrying pMP-fitB (A) or pMP-fitA (B) were grown in LB (open bar) or LB with 100µM 2, 2’-dipyridyl (filled bar). Star (* ) represents statistical significant (p<0.05). C), Gene expression levels measured using quantitative RT-PCR analysis. RNA was isolated from bacteria grown in LB for 3 hours. Strains used were: E. coli i484; oy071 (i484, fur::DHFR-1), oy077 (fitR::kan-2), and oy078 (fur and fitR double mutant). Results were shown as fold of change: ratio of gene expression levels under other conditions to the expression level in E. coli i484 (open bar). Values are the means from three independent experiments.