Figure 1
Fur directly represses the expression of ryhB . (A) The β-galactosidase activities of the K. pneumoniae CG43S3ΔlacZ strain and the isogenic fur deletion mutant carrying pRyhB15 (P ryhB ::lacZ) were determined from overnight cultures grown in LB with or without Dip. The plasmids pRK415 (vector control) and pfur were introduced into Δfur to observe the complement effect. The average of triplicate experiments is shown. Error bars indicate standard deviations. (B) EMSA of the recombinant His6::Fur and the ryhB promoter regions, as indicated in the margin. DNA was incubated with an increasing amount of His6::Fur for 30 min, and then loaded onto a 5% non-denaturing polyacrylamide gel. The gel was stained with SYBR Green EMSA stain and photographed. P ryhB * indicates deletion of the fur box in P ryhB . (C) Assessment of the binding of Fur to the ryhB promoter by using the FURTA. E. coli H1717 strains carrying the vector control, pT7-7, or the P1 region harboured on pT7-7 are indicated. A red colony (Lac+) is considered to have a FURTA-positive phenotype.