Listeria monocytogenes
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PROVIDER: PRJNA106563 | ENA |
REPOSITORIES: ENA
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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: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: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:Comparison of Listeria monocytogenes transcripts in different growth conditions (exponential phase 37 degrees C, stationary phase 37 degrees C, exponential phase 30 degrees C, hypoxia, human blood, murine intestinal lumen) and different mutant strains (wild-type versus prfA, sigB and hfq deletion mutants).
2009-04-24 | E-MEXP-2142 | biostudies-arrayexpress
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:This study was conducted to evaluate which SigB regulator proteins participated in SigB activation of Listeria monocytogenes rpsUG50C mutants.
2024-02-28 | PXD045800 | Pride
Project description:The foodborne pathogen Listeria monocytogenes has the ability to develop biofilm in food-processing environment, which becomes a major concern for the food safety. PrfA, a key transcriptional activator that regulates most of the known listerial virulence gene expression, has been shown to promote L. monocytogenes biofilm formation. In this study, the whole genome microarray was used to identify differentially expressed genes associated with the putative interaction between biofilm formation and PrfA in L. monocytogenes. Comparative transcriptome analyses indicated over 21.9% of the L. monocytogenes EGDe genes (627 out of 2857 predicted) were altered in their expression in biofilm cells relative to planktonic cell populations. These genes were classed into different functional categories which cover most of the biochemical functions encountered in bacterial cells, especially involved in ion transport, DNA repair, and cell wall biosynthesis based on significant enrichment of GO terms. Among them, 185 genes were identified to be associated with PrfA and biofilm formation by comparison of the whole gene expression profiles of L. monocytogenes EGDe and its M-NM-^TprfA mutant. The expression tendency of these PrfA-associated and biofilm-specific genes were mainly opposite in M-NM-^TprfA biofilm, and most of them are involved in phage-related function, membrane bioenergetics, and cell wall. Our results indicated that L. monocytogenes biofilm formation is probably controlled by the complex regulation network involved variable genes required for the different biological pathways. This regulatory network is modified in the prfA deletion mutant in order to maintain its stable biofilm lifestyle. Gene expression of planktonic cells and biofilm cells in Listeria monocytogenes EGDe and prfA isogenic deletion strain EGDeM-NM-^TprfA with cultivated in MEM and BHI for 48 hours, were mesasued using Agilent Listeria monocytogenes customized whole-genome microarray 8x15 array. Three replicates.
2013-05-01 | E-GEOD-43052 | biostudies-arrayexpress
Project description:Listeria monocytogenes strain 10403S has been studied extensively for stress response activity toward multiple stressors (acid, osmotic, cold, high temperature, etc.) as well as multiple stress regulons (SigB, CtsR, HrcA, etc.). Here we aimed to determine the transcriptional response of Listeria monocytogenes in early log phase towards the strong oxidative stress imposed by ClO2. The elucidation of such a response allows for further a more completel understanding of the mechanism of inactivation by sanitizers, specifically ClO2.
2014-03-07 | GSE48187 | GEO
Project description:Phosphopeptides were identified in Listeria monocytogesn strain constitutivally expressing PrfA. Also, the phosphoproteins and proteins were identified that are overexpressed/underextressed in response to PrfA.
2014-10-29 | PXD001108 | Pride
Project description:Listeria monocytogenes is well known to have the ability to survive and grow under a variety of stress conditions. The ability to survive and grow under osmotic stress conditions in particular appears to be important for both growth in certain foods and food associated environments as well as for host infection. To characterize the contributions of transcriptional regulators important for stress response and virulence (i.e., Sigma B - σB and PrfA), we initially analyzed three L. monocytogenes parent strains and isogenic mutants ( delta sigB, delta prfA, and delta sigB delta prfA), representing different serotypes and lineages, for their ability to grow in BHI with 11% NaCl (1.9M) at 25°C. No significant differences were observed in terms of growth between the parent strains and their respective mutants lacking prfA (i.e. delta prfA, and delta sigB delta prfA mutant strains). While for all strains, the delta sigB mutant showed a prolonged lag phase as compared to the parent strains, maximum growth rates were only reduced for the delta sigB mutant of lineage I and IV strains. Interestingly, for the serotype 1/2b strain, the delta sigB mutant reached a higher maximum cell density than the parent strain or the delta prfA mutant. Caco-2 intestinal epithelial cells invasion assays and hemolytic activity assays showed a significant role for σB in the former and for PrfA in the latter. To initially explore the mechanism that may contribute to the extended lag phase in the delta sigB mutant, microarray was performed to compare transcript levels between the lineage I, serotype 1/2b, parent strain and its isogenic delta sigB mutant in lag phase at 25°C in the presence of 11% NaCl. Microarray data showed significant lower and higher transcript levels for 135 and 173 genes, respectively, in the parent strain as compared to the delta sigB strains. Overall, 51 of the 173 σB up-regulated genes had previously been found among the 249 σB-dependent genes identified in a microarray study conducted in stationary phase cells, indicating that up to 122 genes may be transcribed in a σB-dependent manner during lag phase under salt stress. Notable genes that showed higher transcript levels in the parent strain include inlD (encoding an internalin protein that may be involved in virulence), sigH (encoding an alternative σ factor), glpK (encoding a glycerol kinase) and resD (encoding a two-component response regulator ResD); while, genes that showed lower transcript levels in the parent strain include dnaK (encoding a dihydroxyacetone kinase), groES (encoding a class I heat-shock protein GroES), grpE (encoding a co-chaperone GrpE) and fri (encoding a non-heme iron-binding ferritin). These data showed that although PrfA does not contribute to growth under osmotic stress at 25°C, σB does contribute to survival of L. monocytogenes under high salt conditions. Moreover, the σB-dependent transcriptome of L. monocytogenes lag phase cells under salt stress was characterized and includes previously identified as well as novel σB-dependent genes, including a number of stress response and virulence-associated genes.
2013-07-20 | GSE49056 | GEO