FIGURE 7.

mRNA levels for selected virulence factor genes in strain SA178R1 and its derivatives expressing the panel of fakB2 mutant alleles. A series of strains were constructed by knocking in a fakB2 mutant allele into the fakB2 gene of strain SA178R1 as described under “Experimental Procedures.” The strains were grown to mid-log phase; RNA was extracted, and the levels of mRNA for a panel of five genes were determined by quantitative real time PCR as described under “Experimental Procedures.” Four genes, ehp, efb, hlgC, and saeP, were measured because they belong to the gene set that is known to be regulated by fatty acid kinase (1). The plsX gene was included as a control gene that is not part of the Fak regulon. All mRNAs were quantified by comparing their expression levels to the gmk calibrator, and the levels in the parent strain SA178R1 were set to 1.