Sigma 28-dependent small RNAs regulate timing of flagella biosynthesis
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli K-12
PROVIDER: GSE174487 | GEO | 2023/09/26
REPOSITORIES: GEO
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Project description:Campylobacter jejuni produces a single flagellum on one or both poles of the cell, the polar flagella not only confer the bacterium darting motility but also involved in its virulence and metabolic processes. FlhF is a lately defined flagella biosynthesis regulator, but how it regulates flagella assembly isn’t clear at present. Previous research had indicated FlhF was associated with gene expression, to understanding its role in flagella system and its correlation with C. jejuni virulence, the global gene expression profiles of C. jejuni NCTC 11168 after inactivation of FlhF was analyzed. Transcriptome analysis revealed that ten genes were significantly differentially expressed with 6 down-regulated and 4 up-regulated, these genes are involved in diverse cellular functions including bacterial chemotaxis, flagellar assembly and two-component system, significance analysis revealed that the pathway of flagellar assembly was remarkable affected. Further studies were focused on the flagella system, FlhF was found play a global role as 63% (41/65) of the flagella genes were down-regulated, it influences flagella gene transcription from the early stage, this effect persists during the synthesis process and has a remarkable impact on the late part. The results above expand our cognition of this regulator, and also helpful for comprehensively and systematically reveal its role in flagella system.
2018-10-03 | GSE87852 | GEO
Project description:Purpose: Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that undergoes swarming motility in response to semisolid conditions with amino acids as a nitrogen source. With a genome encoding hundreds of potential intergenic small RNAs (sRNAs), P. aeruginosa can easily adapt to different conditions and stresses. We previously identified 20 sRNAs dysregulated under swarming conditions and here provide phenotypic characterization for these sRNAs. Methods: Here, these sRNA were overexpressed in strain PAO1 and subjected to an array of phenotypic screens. Results: Overexpression of prrH resulted in decreased swimming motility, while a ∆prrH mutant had decreased cytotoxicity and increased pyoverdine production. Overexpression of the previously uncharacterized PA2952.1 resulted in decreased swarming and swimming motility, increased gentamicin and tobramycin resistance under swarming conditions, and increased trimethoprim susceptibility. RNA-Seq and proteomics were performed on the wildtype overexpressing PA2952.1 cf. the empty vector control under swarming conditions, and revealed the differential expression of 784 genes and differential abundance of 445 proteins. Amongst these were found 82 transcriptional regulators, two-component systems, sigma and anti-sigma factors. Downstream effectors included downregulated pili, dysregulated flagellar genes, the upregulated efflux pump MexGHI-OpmD, the upregulated arn operon, and downregulated DNA synthesis genes. Genes involved in iron and zinc uptake were also dysregulated, and certain pyoverdine and phenazine genes were upregulated. Conclusions: Overall, the sRNAs PA2952.1 and prrH appeared to be involved in regulating virulence-related programs in P. aeruginosa, including iron acquisition and motility.
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Project description:Abstract of associated manuscript: The Bacillus subtilis extracytoplasmic function (ECF) sigma(M) factor is activated by cell envelope stress elicited by antibiotics, and by acid, heat, ethanol and superoxide stresses. Here, we have used several complementary approaches to identify genes controlled by sigma(M). In many cases, expression is only partially dependent on sigma(M) because of both overlapping promoter recognition with other ECF sigma factors and the presence of additional promoter elements. Genes regulated by sigma(M) have a characteristic pattern of induction in response to cell envelope-acting antibiotics as evidenced by hierarchical clustering analysis. sigma(M) also contributes to the expression of the Spx transcription factor and thereby indirectly regulates genes of the Spx regulon. Cell envelope stress responses also include regulons controlled by sigma(W), sigma(B) and several two-component regulatory systems (e.g. LiaRS, YycFG, BceRS). Activation of the sigma(M) regulon increases expression of proteins functioning in transcriptional control, cell wall synthesis and shape determination, cell division, DNA damage monitoring, recombinational repair and detoxification.
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Project description:Genetically engineered Salmonella Typhimurium are potent vectors for prophylactic and therapeutic measures against pathogens as well as cancer. This is based on the potent adjuvanticity that supports strong immune responses. The physiology of Salmonella is well understood. It simplifies engineering of both enhanced immune-stimulatory properties as well as safety features, thus, resulting in an appropriate balance between attenuation and efficacy for clinical applications. A major virulence factor of Salmonella is the flagellum. It is also a strong pathogen-associated molecular pattern recognized by extra- and intracellular receptors of immune cells of the host. At the same time, it represents a serious metabolic burden. Accordingly, the bacteria evolved tight regulatory mechanisms that control flagella synthesis in vivo. Here, we systematically investigated the immunogenicity and adjuvant properties of various flagella mutants of Salmonella in vitro and in a mouse cancer model in vivo. We found that mutants lacking the flagellum-specific ATPase FliHIJ or the inner membrane ring FliF displayed the greatest stimulatory capacity and strongest anti-tumor effects, while remaining safe in vivo. Scanning electron microscopy revealed the presence of outer membrane vesicles in the ΔfliF and ΔfliHIJ mutants. Finally, the combination of the ΔfliF and ΔfliHIJ mutations with our previously described attenuated and immunogenic background strain SF102 displayed strong efficacy against the highly resistant cancer cell line RenCa. We thus conclude that manipulating flagella biosynthesis has great potential for the construction of highly efficacious and versatile Salmonella vector strains.
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Project description:Shewanella oneidensis MR-1 was grown on electrodes in electrochemical flow cells (EFC), and the transcriptome profiles of electrode-attached MR-1 cells were compared under electrolyte-flow and static (non-flow) conditions. The results revealed that the SO_3096 gene encoding a putative extracytoplasmic function (ECF) sigma factor, as well as genes related to cyclic-di-guanosine monophosphate and flagella synthesis (e.g., SO_3556 and flrC) and c-type cytochrome maturation (dsbD), was significantly up-regulated under the electrolyte-flow condition. Compared to wild-type MR-1 (WT), a deletion mutant of SO_3096 (∆SO_3096) showed an impaired biofilm formation and a decreased current generation in EFC, suggesting that the ECF sigma factor encoded by this gene is involved in the regulation of biofilm formation and current generation under electrolyte-flow conditions. We also compared the transcriptome profiles of WT and ∆SO_3096 grown in EFC, confirming that many genes up-regulated under the electrolyte-flow condition, including dsbD, were down-regulated in ∆SO_3096. Transcription analysis using lacZ as a reporter gene showed that the promoter of dsbD is activated in the presence of SO_3096. Measurement of current generation by a dsbD-deletion mutant revealed that this gene is essential for electron transfer to electrodes. These results suggest that the SO_3096 protein serves as an ECF sigma factor that regulates cellular functions related to electroactive biofilm formation under electrolyte-flow conditions.
2020-06-01 | GSE142642 | GEO
Project description:Shewanella oneidensis MR-1 was grown on electrodes in electrochemical flow cells (EFC), and the transcriptome profiles of electrode-attached MR-1 cells were compared under electrolyte-flow and static (non-flow) conditions. The results revealed that the SO_3096 gene encoding a putative extracytoplasmic function (ECF) sigma factor, as well as genes related to cyclic-di-guanosine monophosphate and flagella synthesis (e.g., SO_3556 and flrC) and c-type cytochrome maturation (dsbD), was significantly up-regulated under the electrolyte-flow condition. Compared to wild-type MR-1 (WT), a deletion mutant of SO_3096 (∆SO_3096) showed an impaired biofilm formation and a decreased current generation in EFC, suggesting that the ECF sigma factor encoded by this gene is involved in the regulation of biofilm formation and current generation under electrolyte-flow conditions. We also compared the transcriptome profiles of WT and ∆SO_3096 grown in EFC, confirming that many genes up-regulated under the electrolyte-flow condition, including dsbD, were down-regulated in ∆SO_3096. Transcription analysis using lacZ as a reporter gene showed that the promoter of dsbD is activated in the presence of SO_3096. Measurement of current generation by a dsbD-deletion mutant revealed that this gene is essential for electron transfer to electrodes. These results suggest that the SO_3096 protein serves as an ECF sigma factor that regulates cellular functions related to electroactive biofilm formation under electrolyte-flow conditions.
2020-06-01 | GSE142641 | GEO
