A mycobacterial DivIVA domain-containing protein involved in cell length and septation.

Mycobacterial cells elongate via polar deposition of cell wall material, similar to the filamentous species, which contain a tip-organizing centre. Coiled-coiled proteins such as DivIVA play an important role in this process. The genome of , the causative agent of tuberculosis, encodes many coiled-coil proteins that are homologous to DivIVA with a potential role in mycobacterial cell elongation. Here we describe studies on , a homologue of . Two previous independent studies showed that was involved in septation (subsequently referred to as ). Contrary to these previous reports, we found to be dispensable for growth in laboratory media by generating a viable null mutant. The mutant strain did, however, show a number of differences, including a change in colony morphology and biofilm formation that could be reversed on complementation with as well as , the homologue from . However, analysis of cell wall lipids did not reveal any alterations in lipid profiles of the mutant strain. Microscopic examination of the mutant revealed longer cells with more septa, which occurred at irregular intervals, often generating mini-compartments, a profile similar to that observed in the previous studies following conditional depletion, highlighting a role for in mycobacterial growth.