Analysis of the role played by CRP family transcriptional regulators in the pathogenesis of Mycobacterium tuberculosis. (360G-Wellcome-078731_Z_05_Z)

This proposal centres on defining the roles of regulatory genes of the CRP family and their relationship to cAMP in the pathogenesis of Mycobacterium tuberculosis, the causative agent of TB. It builds upon our recent work in which we showed that the Rv3676 gene coding for a cAMP-receptor protein (CRP)-like protein is required for a normal infection in a mouse model of TB and that Rv3676 is a direct transcriptional regulator of, among other genes, rpfA, coding for a resuscitation promoting factor, implicating Rv3676 in the reactivation of dormant infections. These observations are very significant because most cases of symptomatic TB occur by reactivation of dormant bacteria. Thus, we wish to determine: the signal perceived by Rv3676, and its relationship to Rv1264, a pH-responsive adenylyl cyclase; the architecture of Rv3676-regulated promoters; and whether Rv3676 has protein-binding partners, with particular focus on the exciting possibility that Rv3676 interacts with one of the WhiB class of actinomycete-specific transcription regulators. In addition, by adapting the approaches (mutant isolation, phenotypic analysis, transcript profiling and biochemical analysis) used by the applicants to reveal the role of Rv3676 in pathogenesis, we propose to characterize a second mycobacterial CRP family member encoded by gene Rv1675