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Coordinated Regulation of Virulence during Systemic Infection of Salmonella enterica Serovar Typhimurium

Figure 4

Validation of microarray results by qRT-PCR for 7 genes located within SPI-2.

The bottom part of the figure shows a map of the type III secretion system located within SPI-2 with the genes that were quantified colored the same as the corresponding bars above. The top part of the figure shows expression of 7 SPI-2 genes in each regulator mutant in comparison to the parental strain when grown in AMM1. The results are plotted on a logarithmic scale. Values were normalized using gyrB mRNA level and represent the average of RNA prepared from three independent biological samples. The results show that mutations in 6 regulators (himD, phoP/phoQ, ssrA/ssrB, slyA, csrA, and ompR/envZ) strongly decrease expression of SPI-2, in 5 strains there is a significant decrease (hnr, rpoE, smpB, crp, hfq) while in the remaining 3 no decrease or even an increase is observed for fruR (the others showing no change are spvR and rpoS).

Figure 4