Fig. 1

Overview of the SigK and PhoPR systems in M. bovis. The SigK system is shown on the left-hand side of the figure. The regulator of the SigK sigma factor, RskA, is mutated in M. bovis leading to constitutive expression of the regulon which includes the mpb83-dipZ-mpb70 locus. MPB83 is a glycosylated lipoprotein and cell wall associated, while MPB70 is secreted. On the right-hand side of the figure the PhoPR system is shown. PhoR senses environmental stimuli that trigger phosphorylation of the PhoP transcriptional regulator; phosphorylated PhoP in turn controls expression of genes involved in diverse functions, such as secretion of virulence effectors and cell wall glycolipid biosynthesis