Localized incorporation of outer membrane components in the pathogen
            <i>Brucella abortus</i>

Vassen, Victoria; Valotteau, Claire; Feuillie, Cécile; Formosa-Dague, Cécile; Dufrêne, Yves F.; Bolle, Xavier De

doi:10.15252/embj.2018100323

Cited by 24 publications

(38 citation statements)

References 77 publications

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“…The Gram-negative alphaproteobacterial order Rhizobiales includes species that lost MreB in the course of evolution (11). Unipolar cell elongation in rod-shaped Rhizobiales, characterized by insertion of new cell wall material at the new cell pole generated by cell division, was reported for several members of this order, such as the plant pathogen Agrobacterium tumefaciens, the plant symbiont Sinorhizobium meliloti, and the animal pathogen Brucella abortus (11)(12)(13). Despite ample evidence for polar cell growth in Rhizobiales, the scaffolding and regulatory factors governing this process remain largely unknown.…”

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confidence: 99%

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Krol

Yau

Lechner

et al. 2020

mBio

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Sinorhizobium meliloti is an alphaproteobacterium belonging to the Rhizobiales. Bacteria from this order elongate their cell wall at the new cell pole, generated by cell division. Screening for protein interaction partners of the previously characterized polar growth factors RgsP and RgsM, we identified the inner membrane components of the Tol-Pal system (TolQ and TolR) and novel Rgs (rhizobial growth and septation) proteins with unknown functions. TolQ, Pal, and all Rgs proteins, except for RgsE, were indispensable for S. meliloti cell growth. Six of the Rgs proteins, TolQ, and Pal localized to the growing cell pole in the cell elongation phase and to the septum in predivisional cells, and three Rgs proteins localized to the growing cell pole only. The putative FtsN-like protein RgsS contains a conserved SPOR domain and is indispensable at the early stages of cell division. The components of the Tol-Pal system were required at the late stages of cell division. RgsE, a homolog of the Agrobacterium tumefaciens growth pole ring protein GPR, has an important role in maintaining the normal growth rate and rod cell shape. RgsD is a periplasmic protein with the ability to bind peptidoglycan. Analysis of the phylogenetic distribution of the Rgs proteins showed that they are conserved in Rhizobiales and mostly absent from other alphaproteobacterial orders, suggesting a conserved role of these proteins in polar growth. IMPORTANCE Bacterial cell proliferation involves cell growth and septum formation followed by cell division. For cell growth, bacteria have evolved different complex mechanisms. The most prevalent growth mode of rod-shaped bacteria is cell elongation by incorporating new peptidoglycans in a dispersed manner along the sidewall. A small share of rod-shaped bacteria, including the alphaproteobacterial Rhizobiales, grow unipolarly. Here, we identified and initially characterized a set of Rgs (rhizobial growth and septation) proteins, which are involved in cell division and unipolar growth of Sinorhizobium meliloti and highly conserved in Rhizobiales. Our data expand the knowledge of components of the polarly localized machinery driving cell wall growth and suggest a complex of Rgs proteins with components of the divisome, differing in composition between the polar cell elongation zone and the septum.

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confidence: 99%

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Krol

Yau

Lechner

et al. 2020

mBio

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“…This exposure may also explain the increased adhesion forces observed during the interaction of the AFM tip with the R-mutant surface. Conversely, in a recent report, AFM analysis of two B. abortus strains, a wild-type and its isogenic mutant Δgmd R lacking O-chain, shows similar degrees of roughness [43]. Structural differences in the LPS core-lipid A moieties of 100 B. microti ΔwbkE+ pBBR-wbkE 1 0 5 83 a Each bacterial strain was inoculated to a group of six 9-weeks-old Balb/c female mice b Over a 25-days period of monitoring, murine death occurred between days 2 and 6 post-inoculation B. microti and B. abortus could be a reason for this divergence.…”

Section: Discussionmentioning

confidence: 81%

Lethality of Brucella microti in a murine model of infection depends on the wbkE gene involved in O-polysaccharide synthesis

et al. 2019

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Brucella microti was isolated a decade ago from wildlife and soil in Europe. Compared to the classical Brucella species, it exhibits atypical virulence properties such as increased growth in human and murine macrophages and lethality in experimentally infected mice. A spontaneous rough (R) mutant strain, derived from the smooth reference strain CCM4915 T , showed increased macrophage colonization and was non-lethal in murine infections. Whole-genome sequencing and construction of an isogenic mutant of B. microti and Brucella suis 1330 revealed that the R-phenotype was due to a deletion in a single gene, namely wbkE (BMI_I539), encoding a putative glycosyltransferase involved in lipopolysaccharide (LPS) O-polysaccharide biosynthesis. Complementation of the R-strains with the wbkE gene restored the smooth phenotype and the ability of B. microti to kill infected mice. LPS with an intact O-polysaccharide is therefore essential for lethal B. microti infections in the murine model, demonstrating its importance in pathogenesis.

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“…It is becoming increasingly accepted in the last few years that the periplasmic spaces and the outer membranes of bacteria are highly organized structures with a defined topology. To achieve this organization, bacteria have evolved mechanisms to compartmentalize the synthetic and/or translocation machinery of the different components of these structures, such as the LPS (15), the peptidoglycan (15,16), secretion systems (17)(18)(19), or adhesins (20,21). For this reason, the assembly of these structures has to be extremely coordinated.…”

Section: Discussionmentioning

confidence: 99%

PhiA, a Peptidoglycan Hydrolase Inhibitor of Brucella Involved in the Virulence Process

et al. 2019

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The peptidoglycan in Gram-negative bacteria is a dynamic structure in constant remodeling. This dynamism, achieved through synthesis and degradation, is essential because the peptidoglycan is necessary to maintain the structure of the cell but has to have enough plasticity to allow the transport and assembly of macromolecular complexes in the periplasm and outer membrane. In addition, this remodeling has to be coordinated with the division process. Among the multiple mechanisms bacteria have to degrade the peptidoglycan are the lytic transglycosidases, enzymes of the lysozyme family that cleave the glycan chains generating gaps in the mesh structure increasing its permeability. Because these enzymes can act as autolysins, their activity has to be tightly regulated, and one of the mechanisms bacteria have evolved is the synthesis of membrane bound or periplasmic inhibitors. In the present study, we identify a periplasmic lytic transglycosidase inhibitor (PhiA) in Brucella abortus and demonstrate that it inhibits the activity of SagA, a lytic transglycosidase we have previously shown is involved in the assembly of the type IV secretion system. A phiA deletion mutant results in a strain with the incapacity to synthesize a complete lipopolysaccharide but with a higher replication rate than the wild-type parental strain, suggesting a link between peptidoglycan remodeling and speed of multiplication.

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Localized incorporation of outer membrane components in the pathogen Brucella abortus

Cited by 24 publications

References 77 publications

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Lethality of Brucella microti in a murine model of infection depends on the wbkE gene involved in O-polysaccharide synthesis

PhiA, a Peptidoglycan Hydrolase Inhibitor of Brucella Involved in the Virulence Process

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