Mycobacterium tuberculosis sigma factor E regulon modulates the host inflammatory response.

Mycobacterium tuberculosis survives in macrophages and usually subverts the bactericidal mechanisms of these phagocytes. The understanding of this host-pathogen interaction is relevant for the development of new treatments for tuberculosis. The adaptation of M. tuberculosis to intracellular life depends on its ability to regulate the expression of its genes. Sigma factors are important bacterial transcription activators that bind to the RNA polymerase and give it promoter specificity. Sigma factor E (SigE) controls the expression of genes that are essential for virulence. We have identified the SigE regulon during infection of macrophages, and we analyzed the impact of this regulon on the transcriptional response of phagocytes. Our results indicate that SigE regulates the expression of genes involved in the maintenance of M. tuberculosis cell envelope integrity and function during macrophage infection. Analysis of the phagocytes' transcriptional response indicates that the SigE regulon is involved in the modulation of the inflammatory response.