Localization of the key cell division determinant FtsZ in Francisella tularensis.

Abstract

Francisella tularensis, the causative agent of tularemia, is a highly infectious gram-negative bacterium capable of replicating within macrophages, leukocytes, dendritic cells and epithelial cells. In addition, F. tularensis also invades erythrocytes. FtsZ, a homologue of eukaryotic tubulin, is an essential cell division protein in almost all bacteria. Polymerization of FtsZ into a contractile ring is a critical first step in division and the FtsZ ring acts in recruiting the cell wall synthesis machinery to the nascent septum. We have generated a recombinant fusion of ftsZftto emgfp (Emerald Green Fluorescent Protein) which can be expressed, in trans, under its presumed native promotor or a strong Francisella promoter (pGRP). As expected, FtsZft-Emgfp can be seen localizing as rings in F. tularensis. Our aim is to utilize fluorescently tagged FtsZ to investigate replication of F. tularensis in a range of in vitro host cell invasion assays and as a marker for viability to study the morphological and physiological differentiation of F. tularensis as it transitions into a viable but non-culturable (VBNC) state. (This research was made possible by NASA West Virginia Space Grant Consortium Training Grant #NNX15A101H and by NIH Grant P20GM103434 to the West Virginia IDeA Network for Biomedical Research Excellence).