The Transcriptional Regulator Np20 Is the Zinc Uptake Regulator in Pseudomonas aeruginosa

ABSTRACT Regulation of metal ion homeostasis is essential to bacterial cell survival, and in most species it is controlled by metal-dependent transcriptional regulators. In this study, we describe a Corynebacterium diphtheriae ferric uptake regulator-family protein, Zur, that controls expression of genes involved in zinc uptake. By measuring promoter activities and mRNA levels, we demonstrate that Zur represses transcription of three genes (zrg, cmrA, and troA) in zinc-replete conditions. All three of these genes have similarity to genes involved in zinc uptake. Transcription of zrg and cmrA was also shown to be regulated in response to iron and manganese, respectively, by mechanisms that are independent of Zur. We demonstrate that the activity of the zur promoter is slightly decreased under low zinc conditions in a process that is dependent on Zur itself. This regulation of zur transcription is distinctive and has not yet been described for any other zur. An adjacent gene, predicted to encode a metal-dependent transcriptional regulator in the ArsR/SmtB family, is transcribed from a separate promoter whose activity is unaffected by Zur. A C. diphtheriae zur mutant was more sensitive to peroxide stress, which suggests that zur has a role in protecting the bacterium from oxidative damage. Our studies provide the first evidence of a zinc specific transcriptional regulator in C. diphtheriae and give new insights into the intricate regulatory network responsible for regulating metal ion concentrations in this toxigenic human pathogen.

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Strategies for Zinc Uptake in Pseudomonas aeruginosa at the Host–Pathogen Interface

Frontiers in Microbiology ◽

10.3389/fmicb.2021.741873 ◽

2021 ◽

Vol 12 ◽

Author(s):

Shuaitao Wang ◽

Juanli Cheng ◽

Yanting Niu ◽

Panxin Li ◽

Xiangqian Zhang ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Drug Targets ◽

Storage Proteins ◽

S100 Protein ◽

Zinc Uptake ◽

Pathogenic Microorganisms ◽

The Face ◽

Host Defense System ◽

Zinc Levels ◽

Zinc Uptake Regulator

As a structural, catalytic, and signaling component, zinc is necessary for the growth and development of plants, animals, and microorganisms. Zinc is also essential for the growth of pathogenic microorganisms and is involved in their metabolism as well as the regulation of various virulence factors. Additionally, zinc is necessary for infection and colonization of pathogenic microorganisms in the host. Upon infection in healthy organisms, the host sequesters zinc both intracellularly and extracellularly to enhance the immune response and prevent the proliferation and infection of the pathogen. Intracellularly, the host manipulates zinc levels through Zrt/Irt-like protein (ZIP)/ZnT family proteins and various zinc storage proteins. Extracellularly, members of the S100 protein family, such as calgranulin C, sequester zinc to inhibit microbial growth. In the face of these nutritional limitations, bacteria rely on an efficient zinc transport system to maintain zinc supplementation for proliferation and disruption of the host defense system to establish infection. Here, we summarize the strategies for zinc uptake in conditional pathogenic Pseudomonas aeruginosa, including known zinc uptake systems (ZnuABC, HmtA, and ZrmABCD) and the zinc uptake regulator (Zur). In addition, other potential zinc uptake pathways were analyzed. This review systematically summarizes the process of zinc uptake by P. aeruginosa to provide guidance for the development of new drug targets.

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Chemical inhibitors of the conserved bacterial transcriptional regulator DksA1 suppressed quorum sensing-mediated virulence of Pseudomonas aeruginosa

Journal of Biological Chemistry ◽

10.1016/j.jbc.2021.100576 ◽

2021 ◽

Vol 296 ◽

pp. 100576

Author(s):

Kyung Bae Min ◽

Wontae Hwang ◽

Kang-Mu Lee ◽

June Beom Kim ◽

Sang Sun Yoon

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Transcriptional Regulator ◽

Chemical Inhibitors

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Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

Microbiology ◽

10.1099/mic.0.022764-0 ◽

2009 ◽

Vol 155 (3) ◽

pp. 712-723 ◽

Cited By ~ 169

Author(s):

Valérie Dekimpe ◽

Eric Déziel

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Virulence Factors ◽

Transcriptional Regulator ◽

Homoserine Lactone ◽

The Other ◽

Virulence Determinants ◽

Late Stationary Phase ◽

Regulatory Systems ◽

Specific Factors

Pseudomonas aeruginosa uses the two major quorum-sensing (QS) regulatory systems las and rhl to modulate the expression of many of its virulence factors. The las system is considered to stand at the top of the QS hierarchy. However, some virulence factors such as pyocyanin have been reported to still be produced in lasR mutants under certain conditions. Interestingly, such mutants arise spontaneously under various conditions, including in the airways of cystic fibrosis patients. Using transcriptional lacZ reporters, LC/MS quantification and phenotypic assays, we have investigated the regulation of QS-controlled factors by the las system. Our results show that activity of the rhl system is only delayed in a lasR mutant, thus allowing the expression of multiple virulence determinants such as pyocyanin, rhamnolipids and C4-homoserine lactone (HSL) during the late stationary phase. Moreover, at this stage, RhlR is able to overcome the absence of the las system by activating specific LasR-controlled functions, including production of 3-oxo-C12-HSL and Pseudomonas quinolone signal (PQS). P. aeruginosa is thus able to circumvent the deficiency of one of its QS systems by allowing the other to take over. This work demonstrates that the QS hierarchy is more complex than the model simply presenting the las system above the rhl system.

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Key role of an ADP − ribose - dependent transcriptional regulator of NAD metabolism for fitness and virulence of Pseudomonas aeruginosa

International Journal of Medical Microbiology ◽

10.1016/j.ijmm.2016.09.007 ◽

2017 ◽

Vol 307 (1) ◽

pp. 83-94 ◽

Cited By ~ 10

Author(s):

Elza Okon ◽

Sarah Dethlefsen ◽

Anna Pelnikevich ◽

Andrea van Barneveld ◽

Antje Munder ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Transcriptional Regulator ◽

Nad Metabolism

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Zinc Uptake Regulator (zur) Gene Involved in Zinc Homeostasis and Virulence of Xanthomonas oryzae pv. oryzae in Rice

Current Microbiology ◽

10.1007/s00284-006-0485-8 ◽

2007 ◽

Vol 54 (4) ◽

pp. 307-314 ◽

Cited By ~ 29

Author(s):

Wanfeng Yang ◽

Yan Liu ◽

Lei Chen ◽

Tongchun Gao ◽

Baishi Hu ◽

...

Keyword(s):

Zinc Uptake ◽

Xanthomonas Oryzae ◽

Zinc Homeostasis ◽

Zinc Uptake Regulator

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Identification of Two Gene Clusters and a Transcriptional Regulator Required for Pseudomonas aeruginosa Glycine Betaine Catabolism

Journal of Bacteriology ◽

10.1128/jb.01393-07 ◽

2007 ◽

Vol 190 (8) ◽

pp. 2690-2699 ◽

Cited By ~ 77

Author(s):

Matthew J. Wargo ◽

Benjamin S. Szwergold ◽

Deborah A. Hogan

Keyword(s):

Pseudomonas Aeruginosa ◽

Glycine Betaine ◽

Transcriptional Regulator ◽

Gene Clusters ◽

Sole Source ◽

Nmr Studies ◽

Demethylase Activity ◽

Growth Experiments ◽

Insight Into ◽

C Nmr

ABSTRACT Glycine betaine (GB), which occurs freely in the environment and is an intermediate in the catabolism of choline and carnitine, can serve as a sole source of carbon or nitrogen in Pseudomonas aeruginosa. Twelve mutants defective in growth on GB as the sole carbon source were identified through a genetic screen of a nonredundant PA14 transposon mutant library. Further growth experiments showed that strains with mutations in two genes, gbcA (PA5410) and gbcB (PA5411), were capable of growth on dimethylglycine (DMG), a catabolic product of GB, but not on GB itself. Subsequent nuclear magnetic resonance (NMR) experiments with 1,2-13C-labeled choline indicated that these genes are necessary for conversion of GB to DMG. Similar experiments showed that strains with mutations in the dgcAB (PA5398-PA5399) genes, which exhibit homology to genes that encode other enzymes with demethylase activity, are required for the conversion of DMG to sarcosine. Mutant analyses and 13C NMR studies also confirmed that the soxBDAG genes, predicted to encode a sarcosine oxidase, are required for sarcosine catabolism. Our screen also identified a predicted AraC family transcriptional regulator, encoded by gbdR (PA5380), that is required for growth on GB and DMG and for the induction of gbcA, gbcB, and dgcAB in response to GB or DMG. Mutants defective in the previously described gbt gene (PA3082) grew on GB with kinetics similar to those of the wild type in both the PAO1 and PA14 strain backgrounds. These studies provided important insight into both the mechanism and the regulation of the catabolism of GB in P. aeruginosa.

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Functional Definition and Global Regulation of Zur, a Zinc Uptake Regulator in a Streptococcus suis Serotype 2 Strain Causing Streptococcal Toxic Shock Syndrome

Journal of Bacteriology ◽

10.1128/jb.01532-07 ◽

2008 ◽

Vol 190 (22) ◽

pp. 7567-7578 ◽

Cited By ~ 41

Author(s):

Youjun Feng ◽

Ming Li ◽

Huimin Zhang ◽

Beiwen Zheng ◽

Huiming Han ◽

...

Keyword(s):

Toxic Shock Syndrome ◽

Streptococcus Suis ◽

Gene Replacement ◽

Zinc Uptake ◽

Zinc Homeostasis ◽

Differentially Expressed ◽

Streptococcal Toxic Shock Syndrome ◽

Toxic Shock ◽

Physiological Tests ◽

Zinc Uptake Regulator

ABSTRACT Zinc is an essential trace element for all living organisms and plays pivotal roles in various cellular processes. However, an excess of zinc is extremely deleterious to cells. Bacteria have evolved complex machineries (such as efflux/influx systems) to control the concentration at levels appropriate for the maintenance of zinc homeostasis in cells and adaptation to the environment. The Zur (zinc uptake regulator) protein is one of these functional members involved in the precise control of zinc homeostasis. Here we identified a zur homologue designated 310 from Streptococcus suis serotype 2, strain 05ZYH33, a highly invasive isolate causing streptococcal toxic shock syndrome. Biochemical analysis revealed that the protein product of gene 310 exists as a dimer form and carries zinc ions. An isogenic gene replacement mutant of gene 310, the Δ310 mutant, was obtained by homologous recombination. Physiological tests demonstrated that the Δ310 mutant is specifically sensitive to Zn2+, while functional complementation of the Δ310 mutant can restore its duration capability, suggesting that 310 is a functional member of the Zur family. Two-dimensional electrophoresis indicated that nine proteins in the Δ310 mutant are overexpressed in comparison with those in the wild type. DNA microarray analyses suggested that 121 genes in the Δ310 mutant are affected, of which 72 genes are upregulated and 49 are downregulated. The transcriptome of S. suis serotype 2 with high Zn2+ concentrations also showed 117 differentially expressed genes, with 71 upregulated and 46 downregulated. Surprisingly, more than 70% of the genes differentially expressed in the Δ310 mutant were the same as those in S. suis serotype 2 that were differentially expressed in response to high Zn2+ concentration, consistent with the notion that 310 is involved in zinc homeostasis. We thus report for the first time a novel zinc-responsive regulator, Zur, from Streptococcus suis serotype 2.

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The Transcriptional Regulator AlgR Is Essential for Pseudomonas aeruginosa Pathogenesis

Infection and Immunity ◽

10.1128/iai.70.11.6083-6093.2002 ◽

2002 ◽

Vol 70 (11) ◽

pp. 6083-6093 ◽

Cited By ~ 49

Author(s):

Stephen E. Lizewski ◽

Derek S. Lundberg ◽

Michael J. Schurr

Keyword(s):

Pseudomonas Aeruginosa ◽

Transcriptional Regulator ◽

Lung Infection ◽

Dual Function ◽

Oxygen Intermediates ◽

Positive Role ◽

Alginate Production ◽

J774 Cells ◽

Negative Role ◽

Myeloperoxidase Assay

ABSTRACT Chronic Pseudomonas aeruginosa lung infection is the major cause of morbidity and mortality in cystic fibrosis (CF) patients. One P. aeruginosa virulence factor unique to CF isolates is overproduction of alginate, phenotypically termed mucoidy. Mucoidy is the result of increased transcription from the algD gene and is activated by the transcriptional regulator AlgR. Mutations in algR result in a nonmucoid phenotype and loss of twitching motility. Additionally, AlgR controls transcription of algC, encoding a dual-function enzyme necessary for both lipopolysaccharide (LPS) and alginate production. Therefore, to determine the effect of algR on P. aeruginosa virulence, an algR mutant was examined for sensitivity to reactive oxygen intermediates, killing by phagocytes, systemic virulence, and the ability to maintain a murine lung infection. We found that P. aeruginosa PAO700 (algR::Gmr) was less lethal than PAO1, as tested in an acute septicemia infection mouse model, and was cleared more efficiently in a mouse pneumonia model. Additionally, the algR mutant (PAO700) was more sensitive to hypochlorite. However, PAO700 was more resistant to hydrogen peroxide and killed less readily in an acellular myeloperoxidase assay than PAO1. There was little difference in killing between PAO1 and PAO700 with macrophage-like J774 cells and human polymorhonuclear leukocytes. Two-dimensional gel analysis of P. aeruginosa algR mutant and wild-type protein extracts revealed 47 differentially regulated proteins, suggesting that AlgR plays both a positive role and a negative role in gene expression. Together, these results imply that AlgR is necessary for virulence and regulates genes in addition to the genes associated with alginate and LPS production and pilus function.

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