FIG 5.

The Lon heat shock protease contributes to the basal level of SPI-1 repression but does not perturb inactivation following growth at 42°C. (A) The sipC-lacZ fusion was used to determine the contribution of lon or clpPX to the regulation of SPI-1 following growth at 42°C. Bacteria were grown as described for Fig. 1B, and reporter activity was measured after overnight growth. The strains used were BTNC0010 to BTNC0012. (B) The hilA-lacZ fusion integrated into the att within the chromosome was used to determine the influence of lon on the reduced expression following growth at 42°C. Samples were cultivated as described for Fig. 1B after overnight growth. Data are from 4 separate experiments. The strains used were BTNC0015 and BTNC0016.