Figure 6.

The CsrA-binding site in the 5′-UTR of the pefA transcript limits expression to host environments. Streptomycin pretreated mice were inoculated with the indicated S. typhimurium mutants and RNA was isolated from the inoculum cultures (inoculum) and from caecal washes collected 72 h after infection (caecum). Transcript levels of fimA (A) and pefA (B) relative to the respective mRNA levels present in the inoculum culture of the S. typhimurium phoN mutant were determined by quantitative real-time PCR. Bars represent geometric means±standard error from at least four different animals. Statistical analysis was performed by a Student’s t-test. n.d., no transcripts detected.