Interaction of the Two Component Regulatory Systems SenX3/RegX3 and MprAB in Mycobacterium tuberculosis.

摘要

The two component regulatory system SenX3-RegX3 of Mycobacterium tuberculosis is required for bacterial survival under low phosphate conditions and activates multiple genes, including the polyphosphate kinase gene (ppk1) during phosphate starvation. However, few studies have determined to which promoters RegX3 binds. Recombinant RegX3 was produced and purified and ppk1 promoter sequences were cloned. This study has found that a crude bacterial lysate containing RegX3, and the purified RegX3 protein, bind to the promoter for ppk1 and it also confirmed that RegX3 binds to its own promoter. Mycobacterium tuberculosis often encounters depleted phosphate conditions in vivo. In this study, we also compared growth of M. tuberculosis in different concentrations of phosphate-depleted media at three days and seven days. The cultures were then plated and initial results showed that there was approximately a ten-fold increase in the growth of M. tuberculosis strain H37Rv in media with 1mM phosphate than in media without added phosphate. By day 7, all strains had reduced growth in phosphate-free media compared to media containing phosphate, indicating that phosphate is an important nutrient for growth of M. tuberculosis .