New insightes in the virulence determinant of M. tuberculosis.

The principal virulence determinant of Mycobacterium tuberculosis (Mtb), the ESX-1 protein secretion system, is positively controlled at the transcriptional level by EspR. Using EspR-specific antibodies in ChIP-Seq experiments (chromatin immunoprecipitation followed by ultra-high throughput DNA sequencing) the group of Prof. Stewart Cole(Global Health Institute) show that EspR binds to at least 165 loci on the Mtb genome. This suggests that rather than functioning as a classical regulatory protein EspR acts globally as a nucleoid-associated protein capable of long-range interactions consistent with a recently established structural model. Thus, rather than serving as a specific activator of a virulence locus, EspR is a novel nucleoid-associated protein, with both architectural and regulatory roles, that impacts cell wall functions and pathogenesis through multiple genes.

Benjamin Blasco et al., PLoS Pathog 8(3): e1002621. doi:10.1371/journal.ppat.1002621 (2012)