Deletion of the C-terminus of polynucleotide phosphorylase increases twitching motility, a virulence characteristic of the anaerobic bacterial pathogen<i>Dichelobacter nodosus</i>

Palanisamy, Suresh; Fletcher, C. Mark; Tanjung, Livia Rossila; Katz, Margaret; Cheetham, Brian F.

doi:10.1111/j.1574-6968.2009.01831.x

Cited by 9 publications

(4 citation statements)

References 28 publications

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“…PNPase has been shown previously to regulate virulence properties in several species of bacteria (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). The results presented in this paper show that PNPase plays an important role in regulating aggregation, adhesion, and virulence in N. meningitidis.…”

Section: Discussionsupporting

confidence: 51%

Neisseria meningitidis Polynucleotide Phosphorylase Affects Aggregation, Adhesion, and Virulence

et al. 2016

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Neisseria meningitidis autoaggregation is an important step during attachment to human cells. Aggregation is mediated by type IV pili and can be modulated by accessory pilus proteins, such as PilX, and posttranslational modifications of the major pilus subunit PilE. The mechanisms underlying the regulation of aggregation remain poorly characterized. Polynucleotide phosphorylase (PNPase) is a 3=-5= exonuclease that is involved in RNA turnover and the regulation of small RNAs. In this study, we biochemically confirm that NMC0710 is the N. meningitidis PNPase, and we characterize its role in N. meningitidis pathogenesis. We show that deletion of the gene encoding PNPase leads to hyperaggregation and increased adhesion to epithelial cells. The aggregation induced was found to be dependent on pili and to be mediated by excessive pilus bundling. PNPase expression was induced following bacterial attachment to human cells. Deletion of PNPase led to global transcriptional changes and the differential regulation of 469 genes. We also demonstrate that PNPase is required for full virulence in an in vivo model of N. meningitidis infection. The present study shows that PNPase negatively affects aggregation, adhesion, and virulence in N. meningitidis.

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Section: Discussionsupporting

confidence: 51%

Neisseria meningitidis Polynucleotide Phosphorylase Affects Aggregation, Adhesion, and Virulence

et al. 2016

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“…In Salmonella, PNPase activity decreases the expression of genes from the pathogenicity islands SPI 1 (containing genes for invasion) and SPI 2 (containing genes for intracellular growth) (Clements et al, 2002). Similarly, in Dichelobacter nodosus, PNPase acts as a virulence repressor in benign strains by decreasing twitching motility (Palanisamy et al, 2009). In contrast, in Yersinia, PNPase modulates the type three secretion system (TTSS) by affecting the steady-state levels of TTSS transcripts and controlling the secretion rate (Rosenzweig et al, 2005(Rosenzweig et al, , 2007.…”

Section: Exonucleases Pnpasementioning

confidence: 99%

The critical role of RNA processing and degradation in the control of gene expression

et al. 2010

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The continuous degradation and synthesis of prokaryotic mRNAs not only give rise to the metabolic changes that are required as cells grow and divide but also rapid adaptation to new environmental conditions. In bacteria, RNAs can be degraded by mechanisms that act independently, but in parallel, and that target different sites with different efficiencies. The accessibility of sites for degradation depends on several factors, including RNA higher-order structure, protection by translating ribosomes and polyadenylation status. Furthermore, RNA degradation mechanisms have shown to be determinant for the post-transcriptional control of gene expression. RNases mediate the processing, decay and quality control of RNA. RNases can be divided into endonucleases that cleave the RNA internally or exonucleases that cleave the RNA from one of the extremities. Just in Escherichia coli there are >20 different RNases. RNase E is a single-strand-specific endonuclease critical for mRNA decay in E. coli. The enzyme interacts with the exonuclease polynucleotide phosphorylase (PNPase), enolase and RNA helicase B (RhlB) to form the degradosome. However, in Bacillus subtilis, this enzyme is absent, but it has other main endonucleases such as RNase J1 and RNase III. RNase III cleaves double-stranded RNA and family members are involved in RNA interference in eukaryotes. RNase II family members are ubiquitous exonucleases, and in eukaryotes, they can act as the catalytic subunit of the exosome. RNases act in different pathways to execute the maturation of rRNAs and tRNAs, and intervene in the decay of many different mRNAs and small noncoding RNAs. In general, RNases act as a global regulatory network extremely important for the regulation of RNA levels.

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“…PNPase influences the virulence of number of human pathogens as well as one animal pathogen. In the Gram-negative Dichelobacter nodosus (the etiological agent of foot root in sheep), PNPase was found to negatively regulate virulence/twitching motility, primarily through its S1 RNA-binding domain (Palanisamy et al, 2010 ). Whether animal or human pathogens, when Gram-negative pathogens, including the yersiniae and salmonellae, are confronted by threatening innate immune cells, a rapid genetic re-programming occurs resulting in anti-host type three secretion system (TTSS) genes becoming upregulated (Cornelis and Van Gijsegem, 2000 ; Cornelis, 2002 ; Viboud and Bliska, 2005 ).…”

Section: Rnase E and The Degradosomementioning

confidence: 99%

The exoribonuclease Polynucleotide Phosphorylase influences the virulence and stress responses of yersiniae and many other pathogens

Rosenzweig

Chopra

2013

Front. Cell. Infect. Microbiol.

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Microbes are incessantly challenged by both biotic and abiotic stressors threatening their existence. Therefore, bacterial pathogens must possess mechanisms to successfully subvert host immune defenses as well as overcome the stress associated with host-cell encounters. To achieve this, bacterial pathogens typically experience a genetic re-programming whereby anti-host/stress factors become expressed and eventually translated into effector proteins. In that vein, the bacterial host-cell induced stress-response is similar to any other abiotic stress to which bacteria respond by up-regulating specific stress-responsive genes. Following the stress encounter, bacteria must degrade unnecessary stress responsive transcripts through RNA decay mechanisms. The three pathogenic yersiniae (Yersinia pestis, Y. pseudo-tuberculosis, and Y. enterocolitica) are all psychrotropic bacteria capable of growth at 4°C; however, cold growth is dependent on the presence of an exoribonuclease, polynucleotide phosphorylase (PNPase). PNPase has also been implicated as a virulence factor in several notable pathogens including the salmonellae, Helicobacter pylori, and the yersiniae [where it typically influences the type three secretion system (TTSS)]. Further, PNPase has been shown to associate with ribonuclease E (endoribonuclease), RhlB (RNA helicase), and enolase (glycolytic enzyme) in several Gram-negative bacteria forming a large, multi-protein complex known as the RNA degradosome. This review will highlight studies demonstrating the influence of PNPase on the virulence potentials and stress responses of various bacterial pathogens as well as focusing on the degradosome-dependent and -independent roles played by PNPase in yersiniae stress responses.

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Deletion of the C-terminus of polynucleotide phosphorylase increases twitching motility, a virulence characteristic of the anaerobic bacterial pathogenDichelobacter nodosus

Cited by 9 publications

References 28 publications

Neisseria meningitidis Polynucleotide Phosphorylase Affects Aggregation, Adhesion, and Virulence

Neisseria meningitidis Polynucleotide Phosphorylase Affects Aggregation, Adhesion, and Virulence

The critical role of RNA processing and degradation in the control of gene expression

The exoribonuclease Polynucleotide Phosphorylase influences the virulence and stress responses of yersiniae and many other pathogens

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