Morphogenic Protein RodZ Interacts with Sporulation Specific SpoIIE in Bacillus subtilis.

Katarína Muchová,Niels Bradshaw,Zuzana Chromiková,Anthony J Wilkinson,Imrich Barák

doi:10.1371/journal.pone.0159076

Katarína Muchová, Niels Bradshaw + Show 3 more

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https://doi.org/10.1371/journal.pone.0159076

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Abstract

The first landmark in sporulation of Bacillus subtilis is the formation of an asymmetric septum followed by selective activation of the transcription factor σF in the resulting smaller cell. How the morphological transformations that occur during sporulation are coupled to cell-specific activation of transcription is largely unknown. The membrane protein SpoIIE is a constituent of the asymmetric sporulation septum and is a crucial determinant of σF activation. Here we report that the morphogenic protein, RodZ, which is essential for cell shape determination, is additionally required for asymmetric septum formation and sporulation. In cells depleted of RodZ, formation of asymmetric septa is disturbed and σF activation is perturbed. During sporulation, we found that SpoIIE recruits RodZ to the asymmetric septum. Moreover, we detected a direct interaction between SpoIIE and RodZ in vitro and in vivo, indicating that SpoIIE-RodZ may form a complex to coordinate asymmetric septum formation and σF activation. We propose that RodZ could provide a link between the cell shape machinery and the coordinated morphological and developmental transitions required to form a resistant spore.

Highlights

Upon starvation, the rod shaped Gram-positive bacterium Bacillus subtilis can enter into a differentiation process termed sporulation
Since the effect of rodZ mutations is more evident in salts medium (SMM) minimal medium, we cultivated cells in this medium supplemented with 1 mM Ca(NO3)2, 10 μM MnCl2 and 1 μM FeSO4 (SMM+salts), salts that are commonly added to Difco sporulation medium (DSM) sporulation medium
Since the cell wall is the main determinant of bacterial cell shape, factors involved in the synthesis and degradation of its major structures play crucial roles in cell shape determination

Summary

Introduction

The rod shaped Gram-positive bacterium Bacillus subtilis can enter into a differentiation process termed sporulation. Sporulation begins with asymmetric cell division which leads to formation of two compartments of unequal size, a smaller forespore and a larger mother cell. The forespore is subsequently engulfed by the mother cell in a process similar to eukaryotic phagocytosis. After a thick proteinaceous shell is deposited around the developing spore, the mother cell lyses releasing a mature, resistant spore. The first clear morphological event in this process is the formation of the asymmetric septum. At the onset of sporulation FtsZ, the eukaryotic tubulin like homologue, is localized at mid-cell where it forms a ring-like structure termed the “Z-ring” [3].

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