Regulation of Listeria monocytogenes PrfA regulon by environmental stimuli in gastrointestinal Tract
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ABSTRACT:
PROVIDER: PRJEB61782 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR11278888_1.fastq.gz | Fastqsanger.gz | |||
| ERR11278888_2.fastq.gz | Fastqsanger.gz | |||
| ERR11278889_1.fastq.gz | Fastqsanger.gz | |||
| ERR11278889_2.fastq.gz | Fastqsanger.gz | |||
| ERR11278890_1.fastq.gz | Fastqsanger.gz |
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Project description:Listeria monocytogenes is a food-borne pathogen which causes listeriosis. It is an intracellular parasite invading the epithelial cells where it escapes from the vacuole into the host cytoplasm to replicate, using actin-based motility to move within and between cells. The intracellular life cycle is well documented whereas the time spent in the lumen of the intestine is poorly understood. The aim of this study was to investigate the mechanism by which L. monocytogenes adapts to the environment of the small intestine prior to invasion. Specifically, to determine if the PrfA regulon, that encodes the virulence factors of L. monocytogenes, is switched on by signals within the intestinal lumen. L. monocytogenes were grown under aerobic or microaerobic conditions with glucose or glycerol as carbon source.
2023-11-24 | E-MTAB-12856 | biostudies-arrayexpress
Project description:Listeria monocytogenes SigB and PrfA are pleiotropic regulators of stress response and virulence gene expression, which have been shown to co-regulate genes in L. monocytogenes. We performed whole genome transcriptional profiling in the presence of PrfA* and active SigB, to identify the overlaps between the PrfA virulence regulon and the SigB stress response regulon. In L. monocytogenes, the PrfA* allele contributes to the activation of virulence genes to a level comparable to that of intracellular growing L. monocytogenes. Our results showed that the core PrfA regulon consists of 12 genes previously described as PrfA regulated. Furthermore, we found that the role of SigB during virulence gene regulation changes, dependent on the presence or absence of PrfA*. In the absence of PrfA*, SigB activated the transcription of virulence genes such as inlA and inlB. In the presence of PrfA*, SigB negatively influenced the transcription of genes in the PrfA core regulon. The observed effect of SigB on the transcript level of PrfA regulated genes was shown to reduce the cytotoxic effect of the PrfA* allele in HepG-2 cells. Our results indicate that the SigB-PrfA regulatory network is important for the adjustment of virulence gene transcription to ensure L. monocytogenes success as an intracellular pathogen. Keywords: comparison of gene expression of regulatory mutants
2008-10-01 | GSE11347 | GEO
Project description:Purpose: The objective of the present study was to refine the PrfA regulatory network using RNA-seq to characterize the L. monocytogenes transcriptome in a wt, ∆prfA, and prfA* under PrfA-inducing conditions. Methods: Sequence reads were aligned to the L. monocytogenes 10403S genome using the BWA-MEM algorithm, version 0.7.3a. The data for coverage per base on the sense and antisense strands were analyzed separately using SAMtools. Differential expression of genes in each strain comparison (wt/∆prfA, wt/prfA*, and prfA*/∆prfA) were analyzed using the baySeq package for R version 2.2.0. Transcripts were considered differentially expressed if the FDR (False Discovery Rate) was ≤ 0.05, the FC (Fold Change) was ≥ 2.0 for up-regulated transcripts and ≤ 0.5 for down-regulated transcripts. Results: Our data indicate that we (i) confirmed transcription of known PrfA-dependent genes and (ii) identified a novel PrfA box and its putative ������A-dependent promoter region. Conclusions: Combined with many studies that have investigated the PrfA regulon and virulence in L. monocytogenes, we have shown tha PrfA directly regulates a small subset of genes; however, using RNA-seq and bioinformatics we were able to identify a novel PrfA-dependent gene and its putative PrfA box. This finding highlights the importance of using advanced approaches to analyze RNA-seq data, which can potentially reveal previously unidentified genes regulated under specific conditions.
2020-10-06 | GSE146507 | GEO
Project description:Listeria monocytogenes SigB and PrfA are pleiotropic regulators of stress response and virulence gene expression, which have been shown to co-regulate genes in L. monocytogenes. We performed whole genome transcriptional profiling in the presence of PrfA* and active SigB, to identify the overlaps between the PrfA virulence regulon and the SigB stress response regulon. In L. monocytogenes, the PrfA* allele contributes to the activation of virulence genes to a level comparable to that of intracellular growing L. monocytogenes. Our results showed that the core PrfA regulon consists of 12 genes previously described as PrfA regulated. Furthermore, we found that the role of SigB during virulence gene regulation changes, dependent on the presence or absence of PrfA*. In the absence of PrfA*, SigB activated the transcription of virulence genes such as inlA and inlB. In the presence of PrfA*, SigB negatively influenced the transcription of genes in the PrfA core regulon. The observed effect of SigB on the transcript level of PrfA regulated genes was shown to reduce the cytotoxic effect of the PrfA* allele in HepG-2 cells. Our results indicate that the SigB-PrfA regulatory network is important for the adjustment of virulence gene transcription to ensure L. monocytogenes success as an intracellular pathogen. Keywords: comparison of gene expression of regulatory mutants The experimental design included 4 mutant strains of L. monocytogenes 10403S (PrfA*, delta prfA, delta prfA delta sigB, and PrfA* delta sigB), of which cDNA generated from 4 biological replicates were hybridized in all possible pairwise comparisons. Data were analyzed using a one way ANOVA in R/MAANOVA to determine significant differences in gene expression among the different strains. A two way ANOVA implemented in R/MAANOVA determined significant differences in gene expression due to the presence or absence of SigB and PrfA.
2010-05-19 | E-GEOD-11347 | biostudies-arrayexpress
Project description:RNA-sequencing of L. monocytogenes under PrfA-inducing conditions refines the PrfA regulon and reveals a putative novel PrfA-dependent gene and its associated PrfA box
| PRJNA610791 | ENA
Project description:Cultivation based analyses were used to determine the resistance of a set of 140 Listeria monocytogenes strains to weak organic acids. Strains of lineage I tended to exhibit greater overall resistant to four different organic acids compared to lineage II strains. Resistant strains also possessed higher survival levels following challenge to pH 2.4 compared to sensitive strains. Transcriptomic analyses were performed to determine genetic responses relevant to growth at mildly acidic conditions (pH 5.0) and to the presence of sodium diacetate. Lineage I and II strain representatives, clinical strain ATCC 19115 and food isolate FW04/0023, were found to exhibit similar transcriptomic changes when habituated to pH 5.0 in brain heart infusion broth (BHIB) relative to growth at pH 7.2 though considerably more divergent responses were detected when 21 mM sodium diacetate was present. Homogeneity in acid habituation-related gene expression was reflected in relatively homogenous SigB, PrfA, HrCA and CodY regulon expression responses. In the presence of sodium diacetate, SigB and PrfA regulon genes found to be upregulated in sigB and prfA null mutants were overall repressed but SigB dependent-gene activation was not evident. L. monocytogenes strains responses to sodium diacetate were observed in different expression trends amongst various functionally-related gene sets and in particular the expression of the PrfA, Atp, Kdp, Cob, Pdu, Eut and Dlt operons; iron transporter and heat shock-related proteins. The results suggest there is diversity in the specific responses to weak organic acids and subsequent cytosolic acidification amongst L. monocytogenes strains though the acid tolerance response itself manifests as a more conserved set of expression responses.
2008-05-29 | GSE11570 | GEO
Project description:The Listeria monocytogenes genome contains more than 20 genes that encode cell surface-associated proteins termed internalins, which are characterized by the presence of multiple leucine-rich repeats. Subsets of internalin genes have been reported previously as transcriptionally regulated by the stress responsive sigma factor B (inlA, inlB, inlC2 and inlD) and the pleiotropic transcriptional activator PrfA (inlA, inlB, inlC). To investigate contributions of σB and PrfA to internalin gene regulation, we designed a sub-genomic microarray containing two probes for each of the 24 internalin-like genes present in the L. monocytogenes 10403S genome. Competitive microarray hybridization was performed on RNA extracted from (i) the 10403S parent strain and an isogenic ΔsigB strain; (ii) 10403S and an isogenic ΔprfA strain; (iii) a 10403S derivative that expresses the constitutively active PrfA* (G155S) and the ΔprfA strain; and (iv) 10403S and an isogenic ΔsigBΔprfA strain. σB- and PrfA-dependent transcription of selected genes was further confirmed by quantitative reverse transcriptase PCR. Statistical analyses of microarray data demonstrated that use of two probes on a microarray for a given target gene yielded more reliable transcriptional profiling information than use of a single probe. The suitability of the PrfA* strain for examining PrfA-dependent gene expression was established quantitatively by the observation that the plcA and prfA transcript levels generated by the PrfA* strain were similar to those obtained from intracellular L. monocytogenes and significantly higher than those in a wildtype strain grown in BHI broth. Among the 24 internalin-like genes examined, 4 and 6 were positively regulated by PrfA and σB, respectively, including inlA and inlB, which were positively regulated by both PrfA and σB. In summary, our findings clearly establish broad roles for both PrfA and σB in regulating L. monocytogenes internalin gene expression Keywords: Listeria monocytogenes, Internalins, sigB, PrfA, Microarrays
2007-04-28 | GSE6421 | GEO
Project description:External signals are key for bacteria to sense their immediate environment and fine-tune gene expression accordingly. The foodborne pathogen Listeria monocytogenes senses a range of environmental cues in order to activate or deactivate the virulence-inducing transcriptional factor PrfA during transition between infectious and saprophytic lifecycles. Chitin is an abundant biopolymer formed from linked β-(1–4)-N-acetyl-D-glucosamine residues associated with fungi, the exoskeleton of insects and often incorporated into foods as a thickener or stabiliser. L. monocytogenes evolved to hydrolyse chitin, presumably, to facilitate nutrient acquisition from competitive environments such as soil where the polymer is abundant. Since mammals do not produce chitin, we reasoned that the polymer could serve as an environmental signal contributing to repression of L. monocytogenes PrfA-dependent expression outside the host. This study shows a significant downregulation of the core PrfA-regulon during virulence-inducing conditions in vitro in the presence of chitin. Our data suggest this phenomenon occurs through a mechanism that differs from PTS-transport of oligosaccharides generated from either degradation or chitinase-mediated hydrolysis of the polymer. Importantly, an indication that chitin can repress virulence expression of a constitutively active PrfA* mutant is shown, possibly mediated via a post-translational modification inhibiting PrfA* activity. To our knowledge, chitin as a molecule with anti-virulence properties against a pathogenic bacterium has not been previously reported. Thus, our findings identify chitin as a signal which may downregulate the virulence potential of the pathogen and may provide an alternative approach towards reducing disease risk.
2020-12-22 | GSE154844 | GEO
Project description:Mus musculus gastrointestinal tract Raw sequence reads
| PRJNA801221 | ENA
Project description:The foodborne pathogen Listeria monocytogenes uses a number of transcriptional regulators, including the negative regulator HrcA, to control gene expression under different environmental conditions and in response to stress. Gene expression patterns of DhrcA stationary phase cells were compared to wt to identify hrcA-dependent genes. We identified 61 HrcA-dependent genes that showed significant expression ratios (adj. P < 0.05), with ≥ 1.5-fold differential expression between ΔhrcA and wt. Combined with microarray analysis, Hidden Markov Model searches show HrcA directly repress at least 8 genes. Keywords: Listeria monocytogenes, HrcA regulon, stationary phase
2007-11-03 | GSE7517 | GEO