Identification and characterization of an essential gene inListeria monocytogenesusing an inducible gene expression system

Abstract

The Listeria monocytogenes gene lmo1594 is a homolog of the Bacillus subtilis cell division gene ezrA. EzrA is a negative regulator of FtsZ ring formation, which is required for efficient cell division as it regulates the frequency and position of Z-rings in the cell and prevents aberrant polar cell division. Previously identified as a putative high pressure (HP) resistance mechanism; conferring enhanced barotolerance when heterologously expressed against an Escherichia coli background; the aim of the current study was to investigate whether lmo1594 plays a role in listerial barotolerance. When the creation of a deletion mutant proved unsuccessful, the role of lmo1594 was addressed by creating a conditional knockout mutant which demonstrated that the gene is in fact essential for cell survival and growth in L. monocytogenes. In order to investigate the effect of lmo1594 on barotolerance, the gene was over-expressed. The over-expression of lmo1594 increased survival levels in L. monocytogenes treated at 300 MPa, but survival levels similar to those of the wild-type strain were observed when treated at a higher pressure (≥400 MPa). In conclusion, this study reveals for the first time that lmo1594 is absolutely essential for listerial cell growth and survival, and also plays an important role in listerial barotolerance.

EzrA, a cell shape regulator contributing to biofilm formation and competitiveness in Streptococcus mutans

“…Mutation of ezrA results in multiple non‐dividing Z rings near the poles in B. subtilis , although with a small or no defect in the viability (Gueiros‐Filho & Losick, ; Levin et al, ). In other species, including S. pneumoniae , Listeria monocytogenes and certain strains of S. aureus (Considine, Sleator, Kelly, Fitzgerald, & Hill, ; Steele et al, ; Thanassi et al, ), the lethality of ezrA knockouts increases. Intriguingly, our results demonstrated that the ezrA‐ deficient S. mutans strain was viable but with a remarkably reduced growth rate and final cell yield, which was in agreement with previous findings using the mutant library of S. mutans (Quivey et al, ).…”

Structural basis for interaction of DivIVA/GpsB proteins with their ligands

“…GpsB:EzrA interactions have been observed by bacterial two‐hybrid analysis in B. subtilis (Claessen et al , ) and S. pneumoniae (Rued et al , ) but not in L. monocytogenes (Cleverley et al , ). B. subtilis ezrA is dispensable (Levin et al , ), whereas it is essential in S. pneumoniae (van Opijnen et al , ) and L. monocytogenes (Considine et al , ), where its depletion causes the characteristic filamentous growth typical for other mutants impaired in Z‐ring formation (Rismondo & Halbedel, unpublished data). Thus, the function of EzrA has either diverged in these species or been backed‐up by non‐homologous protein(s) in B. subtilis .…”

Regulation of bacterial cell wall growth

“…In S. aureus , an ezrA deletion results in enlarged cells with unusual patterns of PG insertion , an observation again consistent with perturbed PBP localisation. Others have reported that the ezrA deletion in S. aureus and L. monocytogenes is lethal.…”