Two Zinc Uptake Systems Contribute to the Full Virulence of Listeria monocytogenes during Growth
            <i>In Vitro</i>
            and
            <i>In Vivo</i>

Corbett, David F.; Wang, Jiahui; Schuler, Stephanie; López-Castejón, Gloria; Glenn, Sarah; Brough, David; Andrew, Peter W.; Cavet, James; Roberts, Ian S.

doi:10.1128/iai.05904-11

Cited by 64 publications

(67 citation statements)

References 36 publications

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“…A few bacterial species have been reported to have more than one zinc uptake system (2). For example, deletion of either of the two zinc uptake systems in Listeria monocytogenes results in no detectable growth defect in zinc-limiting medium, but deletion of both systems results in severe growth defects in vitro and in vivo (17). For V. cholerae, Znu-ABC apparently plays a predominant role in zinc uptake in vitro, but in vivo both ZnuABC and ZrgABCDE are equally important.…”

Section: Resultsmentioning

confidence: 99%

“…Consequently, many bacterial pathogens must be able to acquire zinc in order to cause disease. A number of pathogens, including E. coli, Haemophilus, Salmonella, Listeria, and Campylobacter, require the ZnuABC transporter system to colonize hosts (12)(13)(14)(15)(16)(17). However, it is less clear how another important pathogen, Vibrio cholerae, regulates its zinc homeostasis in different environmental niches and whether zinc uptake systems contribute to its pathogenesis.…”

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confidence: 99%

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Dual Zinc Transporter Systems in Vibrio cholerae Promote Competitive Advantages over Gut Microbiome

et al. 2015

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Zinc is an essential trace metal required for numerous cellular processes in all forms of life. In order to maintain zinc homeostasis, bacteria have developed several transport systems to regulate its uptake. In this study, we investigated zinc transport systems in the enteric pathogen Vibrio cholerae, the causative agent of cholera. Bioinformatic analysis predicts that two gene clusters, VC2081 to VC2083 (annotated as zinc utilization genes znuABC) and VC2551 to VC2555 (annotated as zinc-regulated genes zrgABCDE), are regulated by the putative zinc uptake regulator Zur. Using promoter reporter and biochemical assays, we confirmed that Zur represses znuABC and zrgABCDE promoters in a Zn 2؉ -dependent manner. Under Zn 2؉ -limiting conditions, we found that mutations in either the znuABC or zrgABCDE gene cluster affect bacterial growth, with znuABC mutants displaying a more severe growth defect, suggesting that both ZnuABC and ZrgABCDE are involved in Zn 2؉ uptake and that ZnuABC plays the predominant role. Furthermore, we reveal that ZnuABC and ZrgABCDE are important for V. cholerae colonization in both infant and adult mouse models, particularly in the presence of other intestinal microbiota. Collectively, our studies indicate that these two zinc transporter systems play vital roles in maintaining zinc homeostasis during V. cholerae growth and pathogenesis. Metal ions are required for many crucial biological processes and are necessary for the survival of living organisms, including bacteria (1). For example, zinc is an essential cofactor for enzymatic reactions, DNA synthesis, and gene expression (2). One study has shown that over 3% of Escherichia coli proteins contain zinc (3). Bacteria have therefore evolved sophisticated systems to control their intracellular zinc concentrations in response to zinc fluctuations in the environment. One system utilized by nearly all bacteria is ZnuABC, a high-affinity zinc uptake system belonging to the ATP binding cassette (ABC) transporter family (4). Three proteins constitute this system: ZnuA, a periplasmic Zn 2ϩ binding protein that captures and delivers zinc to ZnuB, which serves as an inner membrane channel, and ZnuC, an ATPase that provides the energy needed for zinc transport (4). On the other hand, zinc levels in bacteria need to be tightly regulated, as excess zinc has deleterious effects on cells, such as prevention of Mn 2ϩ intracellular accumulation (5) and inhibition of enzymes (6). Zinc transport genes are generally controlled by Zur, a member of the Fur protein family of metal-dependent transcriptional regulators (7). Under zinc-replete conditions, Zur binds free Zn 2ϩ . The Zur-Zn complex then binds to the promoter of znuABC, thus blocking the binding of RNA polymerase (8). Under zinc-deficient conditions, the zinc binding sites of Zur are unoccupied, leading to the destabilization of Zur and the inability to bind and repress znuABC transcription, thus allowing zinc acquisition. In some bacteria, in addition to repressing Zn 2ϩ uptake transporters, Zur can a...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Dual Zinc Transporter Systems in Vibrio cholerae Promote Competitive Advantages over Gut Microbiome

et al. 2015

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“…Zinc uptake systems are known to be important for virulence in many bacteria (59,60). However, in virulence assays using N. benthamiana as the host plant, growth either in LB (a zinc-replete condition) or in LB plus 0.5 mM EDTA (a zinc-depleted condition) had no effect on the virulence of A. tumefaciens mutant strains lacking zinc uptake genes compared to the wild type.…”

Section: Discussionmentioning

confidence: 98%

“…Listeria monocytogenes contains two zinc permease systems, ZurAM and ZinABC, which are regulated by Zur (60). The presence of two high-affinity zinc uptake systems helps these bacteria to survive in diverse zinc-limiting environments and during infection.…”

Section: Discussionmentioning

confidence: 99%

Agrobacterium tumefaciens Zur Regulates the High-Affinity Zinc Uptake System TroCBA and the Putative Metal Chaperone YciC, along with ZinT and ZnuABC, for Survival under Zinc-Limiting Conditions

Chaoprasid

Dokpikul

Johnrod

et al. 2016

Appl Environ Microbiol

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Agrobacterium tumefaciens has a cluster of genes (Atu3178, Atu3179, and Atu3180) encoding an ABC-type transporter, here named troA, troB, and troC, respectively, which is shown here to be a zinc-specific uptake system. Reverse transcription (RT)-PCR analysis confirmed that troA, troB, and troC are cotranscribed, with troC as the first gene of the operon. The yciC (Atu3181) gene is transcribed in the opposite orientation to that of the troCBA operon and belongs to a metal-binding GTPase family. Expression of troCBA and yciC was inducible under zinc-limiting conditions and was controlled by the zinc uptake regulator, Zur. Compared to the wild type, the mutant strain lacking troC was hypersensitive to a metal chelator, EDTA, and the phenotype could be rescued by the addition of zinc, while the strain with a single yciC mutation showed no phenotype. However, yciC was important for survival under zinc limitation when either troC or zinT was inactivated. The periplasmic zinc-binding protein, ZinT, could not function when TroC was inactivated, suggesting that ZinT may interact with TroCBA in zinc uptake. Unlike many other bacteria, the ABC-type transporter ZnuABC was not the major zinc uptake system in A. tumefaciens. However, the important role of A. tumefaciens ZnuABC was revealed when TroCBA was impaired. The strain containing double mutations in the znuA and troC genes exhibited a growth defect in minimal medium. A. tumefaciens requires cooperation of zinc uptake systems and zinc chaperones, including TroCBA, ZnuABC, ZinT, and YciC, for survival under a wide range of zinc-limiting conditions. IMPORTANCEBoth host and pathogen battle over access to essential metals, including zinc. In low-zinc environments, physiological responses that make it possible to acquire enough zinc are important for bacterial survival and could determine the outcome of hostpathogen interactions. A. tumefaciens was found to operate a novel pathway for zinc uptake in which ZinT functions in concert with the high-affinity zinc importer TroCBA. Zinc is an essential metal for bacteria because it is required for the functions of many enzymes and proteins (1, 2). However, zinc overload is toxic to cells (3-7). Bacteria have mechanisms to maintain zinc homeostasis via the coordinated response of genes involved in zinc uptake, efflux, and storage (8-13). The zinc uptake regulator Zur is a transcriptional regulator belonging to the Fur family and functions as a repressor of zinc uptake genes, including znuABC and zinT (10). To prevent excessive amounts of zinc in cells under high-zinc conditions, Zur uses Zn 2ϩ as its cofactor to bind to a conserved AT-rich sequence, called the Zur box (14), found in the promoter region of the zinc uptake genes, leading to inhibition of gene expression (15)(16)(17). ZnuA is a periplasmic protein that binds zinc and transfers it to the membrane permease ZnuB and the ATPase ZnuC (15). The ZinT protein is a periplasmic zinc-binding protein (18-21) that has been shown to directly interact with and assist ZnuABC i...

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“…It is worth noting that recent studies have shown that the production of multiple proteins involved in zinc uptake is not limited to bacteria expressing ZinT. For example, Listeria monocytogenes expresses two ABC-type Zinc importers, both contributing to full virulence [47], while in Streptococcus pneumoniae the zinc importer AdcAII (a ZnuA homologue) can form a complex with the zinc-binding surface protein PhtD, suggesting that this interaction contributes to the efficiency of the zinc uptake mechanism [48].…”

Section: Discussionmentioning

confidence: 99%

The Salmonella enterica ZinT structure, zinc affinity and interaction with the high-affinity uptake protein ZnuA provide insight into the management of periplasmic zinc

Ilari

Alaleona

Tria

et al. 2014

Biochimica et Biophysica Acta (BBA) - General Subjects

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Background: In Gram-negative bacteria the ZnuABC transporter ensures adequate zinc import in Zn(II)-poor environments, like those encountered by pathogens within the infected host. Recently, the metal-binding protein ZinT was suggested to operate as an accessory component of ZnuABC in periplasmic zinc recruitment. Since ZinT is known to form a ZinT-ZnuA complex in the presence of Zn(II) it was proposed to transfer Zn(II) to ZnuA. The present work was undertaken to test this claim. Methods: ZinT and its structural relationship with ZnuA have been characterized by multiple biophysical techniques (X-ray crystallography, SAXS, analytical ultracentrifugation, fluorescence spectroscopy). Results: The metal-free and metal-bound crystal structures of Salmonella enterica ZinT show one Zn(II) binding site and limited structural changes upon metal removal. Spectroscopic titrations with Zn(II) yield a K D value of 22 ± 2 nM for ZinT, while those with ZnuA point to one high affinity (K D b 20 nM) and one low affinity Zn(II) binding site (K D in the micromolar range). Sedimentation velocity experiments established that Zn(II)-bound ZinT interacts with ZnuA, whereas apo-ZinT does not. The model of the ZinT-ZnuA complex derived from small angle X-ray scattering experiments points to a disposition that favors metal transfer as the metal binding cavities of the two proteins face each other. Conclusions: ZinT acts as a Zn(II)-buffering protein that delivers Zn(II) to ZnuA. General significance: Knowledge of the ZinT-ZnuA relationship is crucial for understanding bacterial Zn(II) uptake.

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Two Zinc Uptake Systems Contribute to the Full Virulence of Listeria monocytogenes during Growth In Vitro and In Vivo

Cited by 64 publications

References 36 publications

Dual Zinc Transporter Systems in Vibrio cholerae Promote Competitive Advantages over Gut Microbiome

Dual Zinc Transporter Systems in Vibrio cholerae Promote Competitive Advantages over Gut Microbiome

Agrobacterium tumefaciens Zur Regulates the High-Affinity Zinc Uptake System TroCBA and the Putative Metal Chaperone YciC, along with ZinT and ZnuABC, for Survival under Zinc-Limiting Conditions

The Salmonella enterica ZinT structure, zinc affinity and interaction with the high-affinity uptake protein ZnuA provide insight into the management of periplasmic zinc

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