Identification of cell cycle regulators in Mycobacterium tuberculosis by inhibition of septum formation and global transcriptional analysis.

In Mycobacterium tuberculosis the mechanism of septum formation and regulation of cell division remains undefined. In other bacterial species FtsZ polymerization and septum formation are influenced through protein interactions in addition to transcriptional regulation, and the combination of these provides tight regulation of this process. However, homologues of proteins known to affect FtsZ assembly have not been identified and substantiated in M. tuberculosis. This suggests that M. tuberculosis may possess unique processes for regulation of septum formation. To begin to address this poorly understood aspect of M. tuberculosis physiology, FtsZ inhibitors were used to block cell division and the effects on bacterial morphology and the transcriptional response were examined. Inhibition of septum formation prevented cell division and led to bacterial filamentation. Microarray-based transcriptional profiling allowed the evaluation of multiple metabolic processes in response to inhibition of septum formation and when coupled with bioinformatics provided a means to identify regulatory elements and other gene products that probably influence septum formation.