Blue Light Sensing in Listeria monocytogenes Is Temperature-Dependent and the Transcriptional Response to It Is Predominantly SigB-Dependent
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PROVIDER: PRJNA542147 | ENA |
REPOSITORIES: ENA
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Project description:In this study the global transcriptional response of L. monocytogenes to blue light was elucidated using an RNAseq-based approach. A transcriptomic analysis of the response to sub-lethal levels of blue light found that the changes in transcription were almost entirely SigB-dependent. A mutant where the light sensing mechanism of RsbL was inactivated through an amino acid substitution (Cys56Ala) was found to have an attenuated response to blue light, but residual activation of SigB-dependent genes suggested that alternative routes for activation of SigB by light are likely to exist.
2019-10-30 | GSE130971 | GEO
Project description: Not available
| S-EPMC6874125 | biostudies-literature
Project description:Background: The Bacillus cereus Sigma B (SigB) dependent general stress response is activated via the two-component RsbKY system, which involves a phosphate transfer from RsbK to RsbY. It has been hypothesized that the Hpr-like phosphocarrier protein (Bc1009) encoded by bc1009 in the SigB gene cluster may play a role in this transfer, thereby acting as a regulator of SigB activation. Alternatively, Bc1009 may be involved in the activation of a subset of SigB regulon members. Results: We first investigated the potential role of bc1009 to act as a SigB regulator but ruled out this possibility as the deletion of bc1009 did not affect the expression of sigB and other SigB gene cluster members. The SigB-dependent functions of Bc1009 were further examined in B. cereus ATCC14579 via comparative proteome profiling (backed up by transcriptomics) of wt, Δbc1009 and ΔsigB deletion mutants under heat stress at 42°C. This revealed 284 proteins displaying SigB-dependent alterations in protein expression levels in heat-stressed cells, including a subgroup of 138 proteins for which alterations were also Bc1009-dependent. Next to proteins with roles in stress defense, newly identified SigB and Bc1009-dependent proteins have roles in cell motility, signal transduction, transcription, cell wall biogenesis, and amino acid transport and metabolism. Analysis of lethal stress survival at 50°C after pre-adaptation at 42°C showed intermediate survival efficacy of Δbc1009 cells, highest survival of wt, and lowest survival of ΔsigB cells, respectively. Additional comparative proteome analysis of non-stressed wt and mutant cells at 30°C revealed 96 proteins with SigB and Bc1009-dependent differences in levels, 51 were also identified under heat stress, and 45 showed significant differential expression at 30°C, including proteins with roles in carbohydrate/ion transport and metabolism. Overlapping functions at 30°C and 42°C included proteins involved in motility, and ΔsigB and Δbc1009 cells showed reduced motility compared to wt cells in swimming assays at both temperatures. Conclusion: our results extend the B. cereus SigB regulon to >300 members, with a novel role of SigB-dependent Bc1009 in the activation of a subregulon of >180 members, conceivably via phosphotransfer-based interactions with other transcriptional regulatory networks.
2023-03-02 | GSE213958 | 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
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:To investigate whether salt-stress dependent activation of SigB is mitigated when cells are pre-loaded with the compatible solute glycine betaine, we analyzed salt induction of the SigB regulon in the presence of the precursor choline at a genome-wide level. The median expression value of SigB-regulated genes was 1.7-fold higher in cells that received choline immediately before salt stress compared to cells where choline was added 60 minutes prior to the salt stress.
2020-03-01 | GSE141882 | GEO
Project description:Acclimation of cyanobacterium Synechocystis sp. PCC6803 to suboptimal conditions is largely dependent on adjustments of gene expression, which is highly controlled by the σ factor subunits of RNA polymerase (RNAP). The SigB and SigD σ factors are close homologues. Here we show that sigB and sigD genes are both induced in bright light and high temperature stresses. Comparison of transcriptomes of the control strain (CS), ΔsigB, ΔsigD, ΔsigBCE (SigD is an only functional group 2 σ factor), and ΔsigCDE (SigD is an only functional group 2 σ factor) strains in standard, bright light and high temperature conditions revealed that the SigB and SigD factors regulate different set of genes, and that SigB and SigD regulons are highly dependent on stress conditions. The SigB regulon is bigger than the SigD regulon at high temperature, whereas in bright light the SigD regulon is bigger the SigB regulon. Furthermore, our results show that favoring the SigB or SigD factor by deleting other group 2 σ factors do not lead to superior acclimation to bright light or high temperature conditions, indicating that all group 2 σ factors play roles in acclimation processes.
2022-01-19 | GSE192357 | GEO
Project description:In this study, RNA-seq was used to compare the transcriptomes of Listeria monocytogenes 10403S::ΔBCHL Prha-sigB and ΔBCHL Prha. RNA-seq was performed on ΔBCHL Prha-sigB and ΔBCHL Prha RNA samples representing three independent biological replicates at log phase in Brain Heart Infusion (BHI) broth under rhamnose induction. Indexed and purified cDNA libraries (6 libraries including 3 replicates for 2 strains) were loaded together onto an independent flow cell without any other samples; sequencing was carried out by running Hiseq 2500 (single-end, 150-bp per read). Reads alignment was carried out using the Burrows-Wheeler Aligner (BWA). Differential expression of genes in different strains was statistically assessed using the BaySeq method. To identify sigB-dependent promoters, a method of moving sliding windows of 50 nt along the whole genome was used to compare the normalized RNA-seq coverage (NRC) between the two strains. Using the standard whole gene differential expression analysis, significant upregulation of 255 genes was found in the sigB overexpressing strain. While with the sliding windiow analysis, 18 σB-dependent promoters were newly identified.
2017-10-31 | GSE94284 | GEO
Project description:Global expression analysis comparing gene expression of wild-type and sigB mutant in the SH1000 background
2016-11-14 | GSE87036 | GEO
Project description:Background. Infections caused by Staphylococcus aureus are associated with significant morbidity and mortality and are an increasing threat not only in hospital settings. The expression of the staphylococcal virulence factor repertoire is known to be affected by the alternative sigma factor B (SigB). However, its impact during infection still is a matter of debate. Methods. Kidney tissue of controls or mice infected with S. aureus HG001 or its isogenic sigB mutant was analyzed by transcriptome profiling to monitor the host response, and additionally expression of selected S. aureus genes was monitored by RT-qPCR. Results. Direct transcript analysis by RT-qPCR revealed significant SigB activity in all mice infected with the wild type strain (WT), but not in its isogenic sigB mutant (p<0.0001). Despite a clear cut difference in the SigB-dependent transcription pattern of virulence genes (clfA, aur, and hla), the host reaction to infection (either WT or sigB mutant) was almost identical. Conclusions. Despite its significant activity in vivo, loss of SigB did not have an effect on the outcome of infection as well as on murine kidney gene expression pattern. Thus, these data support the role of SigB as virulence modulator rather than being a virulence determinant by itself.
2011-10-24 | GSE28540 | GEO