FIG 2.

Expression profiles of ESX-1 genes show differential PhoP regulation in clinical and laboratory strains of M. tuberculosis. qRT-PCR measurements of representative genes from ESX-1 and extended ESX-1 regions involved in ESAT-6 secretion, showing PhoP-dependent expression in the H37Rv, MT103, and GC1237 strains. Expression of esxA and esxB genes correlates with that of the whiB6 gene in Fig. 1C, showing a divergent PhoP regulation in H37Rv compared to those of the MT103 and GC1237 clinical strains. In contrast, PhoP regulation of the espA, espC, and espD genes is independent of the genetic background. Bars indicate fold change in gene expression relative to the sigA gene used as an endogenous control. Results represent the average of three independent experiments, and error bars indicate the SD of the mean.