Interaction of the Morphogenic Protein RodZ with the Bacillus subtilis Min System.

Katarína Muchová,Romana Valenčíková,Zuzana Chromiková,Imrich Barák

doi:10.3389/fmicb.2017.02650

Katarína Muchová, Romana Valenčíková + Show 2 more

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https://doi.org/10.3389/fmicb.2017.02650

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Abstract

Vegetative cell division in Bacillus subtilis takes place precisely at the middle of the cell to ensure that two viable daughter cells are formed. The first event in cell division is the positioning of the FtsZ Z-ring at the correct site. This is controlled by the coordinated action of both negative and positive regulators. The existence of positive regulators has been inferred, but none have presently been identified in B. subtilis. Noc and the Min system belong to negative regulators; Noc prevents division from occurring over the chromosomes, and the Min system inhibits cell division at the poles. Here we report that the morphogenic protein, RodZ, an essential cell shape determinant, is also required for proper septum positioning during vegetative growth. In rodZ mutant cells, the vegetative septum is positioned off center, giving rise to small, round, DNA-containing cells. Searching for the molecular mechanism giving rise to this phenotype led us to discover that RodZ directly interacts with MinJ. We hypothesize that RodZ may aid the Min system in preventing non-medial vegetative division.

Highlights

Cell division is a complex, highly coordinated process for producing viable progeny
We demonstrate that RodZ directly interacts with MinJ, a member of Min system
Escherichia coli strains were grown in LB (Ausubel et al, 2001), B. subtilis cells were grown in LB, DSM, or SMS/SMM (Spizizzen’s minimal salts medium) (Harwood, 1990)

Summary

Introduction

Cell division is a complex, highly coordinated process for producing viable progeny. Cell division (cytokinesis) must occur at the right place and at the right time in order to ensure that two daughter cells with a complete DNA complement form. The efficient coordination of chromosome replication, chromosome segregation, and cell division is crucial for all dividing cells. In bacteria growing in rich medium, chromosome replication, chromosome segregation, and the assembly of cell division machinery all occur simultaneously (Hajduk et al, 2016). The Z-ring recruits over 20 other division proteins to form a divisome (den Blaauwen et al, 2017). In Bacillus subtilis, divisome formation takes place in two steps: first, FtsZ assembles early and concomitantly with FtsA, SepF, ZapA, and EzrA; after a delay, other division proteins such as FtsL, DivIB, FtsW, Pbp2B and various regulatory proteins (GpsB, DivIVA, MinJ, MinD, and MinC) are recruited to midcell (Gamba et al, 2009; Errington and Wu, 2017)

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