The intergenic region of the yscW-lcrF operon is implicated in the temperature control of LcrF production.
(A) Schematic presentation of the reporter gene fusion harboring the yscW-lcrF intergenic region and different portions of yscW under control of the PBAD promoter. (B) E. coli K-12 harboring the different PBAD::yscW-lcrF-lacZ reporter plasmids (pED10, pED11 and pKB14) or the PBAD::gnd-lacZ control plasmid (pED05) were grown overnight in LB medium at 25°C or 37°C in the presence of 0.05% arabinose. β-Galactosidase activity from overnight cultures was determined and is given in mmol min−1 mg−1 for comparison. The data represent the average ± SD from at least three different experiments each done in duplicate. Data were analyzed by the Student's t test. Stars indicate the reporter activity that differed significantly between 25°C and 37°C with ** (P<0.01), and *** (P<0.001).