FIG 6.

Both polyphosphate kinase and the Lon protease antagonize virulence gene expression in F. tularansis. (A) Effect of polyphosphate kinase and the Lon protease on expression of the iglA and FTL_1219 genes. The relative abundance of the iglA and FTL_1219 transcripts was determined in cells of the indicated strains by qRT-PCR. The figure shows data from a representative experiment with biological duplicates. Transcripts were normalized to tul4, and error bars represent ±1 standard deviation from the value (calculated using the mean threshold cycle) (B) Effect of polyphosphate kinase and the Lon protease on IglC abundance. The abundance of IglC in cells of the indicated strains was determined by Western blotting with an antibody against IglC. An antibody against GroEL was used as a loading control. Duplicate biological samples were tested for each strain, and a representative data set is shown.