Pseudomonas aeruginosa promoters which contain a conserved GG-N10-GC motif but appear to be RpoN-independent

Savioz, Armand; Zimmermann, A; Haas, Dieter

doi:10.1007/bf00279533

Cited by 23 publications

(11 citation statements)

References 47 publications

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“…By using the MEME suite, a 14-bp RpoN-binding sequence, GG(C/T/A)(A/G/C)(C/T/A)(G/A/C)(G/C)N 3 (T/A) (T/C)GC, was confirmed ( Fig. 1C), which is consistent with the previously identified motif (31,44).…”

Section: Resultssupporting

confidence: 88%

RpoN-Dependent Direct Regulation of Quorum Sensing and the Type VI Secretion System in Pseudomonas aeruginosa PAO1

Shao

Zhang

et al. 2018

J Bacteriol

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is a Gram-negative opportunistic pathogen of humans, particularly those with cystic fibrosis. As a global regulator, RpoN controls a group of virulence-related factors and quorum-sensing (QS) genes in To gain further insights into the direct targets of RpoN, the present study focused on identifying the direct targets of RpoN regulation in QS and the type VI secretion system (T6SS). We performed chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) that identified 1,068 binding sites of RpoN, mostly including metabolic genes, a group of genes in QS (, , and) and the T6SS ( and ). The direct targets of RpoN have been verified by electrophoretic mobility shifts assays (EMSA), reporter assay, reverse transcription-quantitative PCR, and phenotypic detection. The ::Tc mutant resulted in the reduced production of pyocyanin, motility, and proteolytic activity. However, the production of rhamnolipids and biofilm formation were higher in the::Tc mutant than in the wild type. In summary, the results indicated that RpoN had direct and profound effects on QS and the T6SS. As a global regulator, RpoN controls a wide range of biological pathways, including virulence in PAO1. This work shows that RpoN plays critical and global roles in the regulation of bacterial pathogenicity and fitness. ChIP-seq provided a useful database to characterize additional functions and targets of RpoN in the future. The functional characterization of RpoN-mediated regulation will improve the current understanding of the regulatory network of quorum sensing and virulence in and other bacteria.

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Section: Resultssupporting

confidence: 88%

RpoN-Dependent Direct Regulation of Quorum Sensing and the Type VI Secretion System in Pseudomonas aeruginosa PAO1

Shao

Zhang

et al. 2018

J Bacteriol

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“…In contrast, the cloned promoter does seem to depend on tHF, at least in part, as the MIC was reduced from 250pgml 1 with the parental strain to 100pgm1-1 with the mutant strain K1299 (pLS102). To our knowledge only one case has been reported in which a strong sequence similarity to -12/-24 promoter consensus does not involve dependency on (~s4 (Savioz et aL, 1993). Moreover, in E. coli IHF is mostly required for the activation of (~54 promoters, suggesting the presence of an unidentified sigma subunit in S. typhiwhich activates transcription in a fashion similar to (~s,, as has been previously suggested (Helmann and Chamberlin, 1988).…”

Section: Influence Of Transcription Modulating Factors On Promoter Acsupporting

confidence: 54%

Identification of Salmonella typhi promoters activated by invasion of eukaryotic cells

Staendner¹,

Rohde²,

Timmis³

et al. 1995

Molecular Microbiology

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The interaction of pathogenic microorganisms with host tissues, and the underlying genetic events which regulate these interactions, are difficult to analyse where no suitable animal model exists. The approach described here, for obtaining information on the genes involved in these interactions, employs an infection system based on the invasion of Henle cells by Salmonella typhi to select promoter-containing DNA sequences able to activate gene expression inside eukaryotic cells. Several DNA fragments exhibiting different promoter strengths and extent of selective activation within eukaryotic cells were identified. Three were selected and characterized according to the expression level of the reporter gene, the polynucleotide sequence, the transcription start, and the dependence upon regulatory proteins. All fragments gave much stronger expression of the reporter gene when the recombinant S. typhi carrier strains invaded cells compared with the expression measured in growth medium. One promoter-containing region exhibited sequence homology to sigma 54-dependent promoters, whereas another appears to be dependent on the stationary-phase RNA polymerase subunit sigma s. S. typhi containing the S1 subunit gene of pertussis toxin cloned under the control of these promoters, selectively expressed the S1 subunit following infection of different phagocytic and non-phagocytic cell lines of human or murine origin. Deletion and point mutant derivatives of two promoters enabled the identification of the main motif required for promoter activity. This method may be helpful for the analysis of pathogenesis in organisms previously difficult to study because of the lack of a convenient animal model, and could provide insights into the chronology and topology of gene expression during infection, including a possible genetic basis for tissue tropism.

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“…AlgD is also under the same promoter than PLC, which is sensitive to the nitrogen source [109] that regulates the anaerobiosis genes. These genes detect the ratio of glutamine to 2-ketoglutarate, which is dependent on O 2 availability [108,110]. Another positive regulator of AlgD is AlgU [111], but the only negative regulator known is the RpoN, a sigma factor, that regulates nitrogen metabolism.…”

Section: Chronic Infection Of P Aeruginosamentioning

confidence: 99%

“…Another positive regulator of AlgD is AlgU [111], but the only negative regulator known is the RpoN, a sigma factor, that regulates nitrogen metabolism. RpoN is increased by disruption of pyrimidine synthesis and decreased by the supplementation with uracil, showing that a high level of RpoN, in the RSCV form, may block the alginate biosynthesis [110,112].…”

Section: Chronic Infection Of P Aeruginosamentioning

confidence: 99%

Host-Pathogen Interaction in the Lung of Patients Infected withPseudomonas aeruginosa

Grumelli¹

2019

Pseudomonas Aeruginosa - An Armory Within

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Pseudomonas aeruginosa is an opportunistic bacterium that can proliferate in the soil, water, and even humans if they are immunologically depressed. During lung infections, P. aeruginosa goes through significant morphological changes turning into the mucoid form after which its eradication becomes almost impossible. Within this chapter, we explore the bioenergetics changes produced within P. aeruginosa during infections in humans and the metabolic pathways that are involved in those changes that lead to chronic infection. 2 transmembrane conductance regulator (CFTR) identified as F508, G542X, G551D, W1282X, R1162X, and N1303K [24, 25]. CF also has co-morbidity such as liver cirrhosis [26] with 18% prevalence [27,28] of P. aeruginosa infection in this subset. Host-bacteria interaction in acute infection Lung changes upon bacterial invasionThe flagella and lipopolysaccharide (LPS) from P. aeruginosa are the first to contact the ciliated epithelial cells [29]. In the airways, these cells are covered by the surfactants containing 45% less NaCl and 600 more K + than in plasma [30], while the alveolar epithelial cells are covered by a surfactant layer that contains mostly phosphatidylcholine (80%) [31] and surfactant proteins A, B, C, and D [32, 33] that bind LPS in a calcium-dependent manner [34]. After the surfactant layer is crossed, the flagellum binds to the epithelial cells through toll-like receptors (TLR) 2, 3, 4 and 5 [35][36][37][38][39][40] that are quickly endocytosed to be degraded in the proteasome. The activated TLR5 induces the macrophages chemoattractants CXCL1, CXCL2, and neutrophil chemokine CCL20, which are inhibited by TLR5 inhibitors [41]. The peptides digested are then presented to macrophages and dendritic cells.When LPS binds to the host cells, where CFTR is also a receptor [42], it upregulates NF-κB at the gene level (Table 1), promoting inflammation [43] by secretion of IL1, IL6, IL8, ICAM-1, and also CXCL1 [44][45][46][47], although in different degrees of regulation. For example, CXCL1 expression is orchestrated by a fatty acid-binding protein (FABP4) that delivers fatty acids from the cytoplasm to the nuclear receptor PPAR. These prompt macrophage signaling through the myeloid differentiation protein-88 (MyD88) to induce cytokine production following engagement of TLRs with LPS [48-51]. Macrophages require MyD88 to produce CXCL1 but also eicosapentaenoic acid and docosahexaenoic acid, both substrates of FABP4. This demonstrates the importance of fatty acid metabolism to promote host resistance to P. aeruginosa, facilitating macrophage-neutrophil cross-talk during the infection [52,53].The T cells also play an important role in acute infection. IL17 producing T cells are expanded [54], via expression of STAT3 and retinoid orphan receptor [55]; these steps are crucial for B cell activation and immunoglobulin release for bacterial clearance [56]. On the contrary, excess of T regulatory cells (Treg) are associated with secondary P. aeruginosa infections, because depletion of Tregs decreases ...

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Pseudomonas aeruginosa promoters which contain a conserved GG-N10-GC motif but appear to be RpoN-independent

Cited by 23 publications

References 47 publications

RpoN-Dependent Direct Regulation of Quorum Sensing and the Type VI Secretion System in Pseudomonas aeruginosa PAO1

RpoN-Dependent Direct Regulation of Quorum Sensing and the Type VI Secretion System in Pseudomonas aeruginosa PAO1

Identification of Salmonella typhi promoters activated by invasion of eukaryotic cells

Host-Pathogen Interaction in the Lung of Patients Infected withPseudomonas aeruginosa

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