RpoN/Sfa2-dependent activation of the Pseudomonas aeruginosa H2-T6SS and its cognate arsenal of antibacterial toxins
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PROVIDER: PRJNA768878 | ENA |
REPOSITORIES: ENA
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Project description:Pseudomonas aeruginosa uses three type six secretion systems (H1-, H2- and H3-T6SS) to manipulate its environment, subvert host cells and compete with microbial competitors. These T6SS machines can be loaded with a variety of effectors/toxins, many being associated with a specific VgrG. How P. aeruginosa transcriptionally coordinates the three main T6SS clusters and the multiple vgrG islands spread through the genome is unknown. Here we show an unprecedented level of control of the regulator RsmA in repressing most known T6SS-related genes. Moreover, it is noticeable that a sigma factor activator (SFA) protein is encoded in each of H2- and H3-T6SS clusters, Sfa2 and Sfa3, respectively. SFA proteins are enhancer binding proteins that usually work in concert with the sigma factor RpoN. Using a combination of RNA-seq, ChIP-seq and molecular biology approaches, we demonstrate that RpoN coordinates the T6SSs of P. aeruginosa by activating the H2-T6SS but repressing the H1- and H3-T6SS. Furthermore, RpoN and Sfa2 control the expression of all H2-T6SS-linked VgrG and effector arsenal to enable very effective interbacterial killing. Such RpoN-dependent control is exerted both directly and indirectly. The function of the SFA protein is specific since the H3-T6SS associated Sfa3 cannot complement loss of Sfa2. Our study further delineates the multiple regulatory mechanisms that modulate the deployment of an arsenal of T6SS effectors likely to respond and adapt to a range of environmental conditions that a versatile organism like P. aeruginosa would encounter.
2022-02-23 | GSE185398 | GEO
Project description:Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen of humans, most notably those with cystic fibrosis or whose immune systems are compromised. As a global regulator, RpoN has been characterized to control a group of virulence-related factors and quorum sensing (QS) genes in P. aeruginosa, but its detailed molecular regulatory mechanism is largely elusive. To further gain insights into the direct targets of RpoN in vivo, this study focused on identifying the potential targets of RpoN directly regulating QS system and T6SS. We performed a chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-seq) assay that identified 1, 068 binding sites of RpoN, including mostly metabolic genes, a group of genes in QS (lasI, rhlI and pqsR) and type VI secretion system (T6SS) (hcpA and hcpB). The direct regulation of these genes by RpoN has been biochemically and genetically verified. Results revealed that, on one hand, the deletion of rpoN resulted in reduced production of pyocyanin, motility and proteolytic activity. On the other hand, the production of rhamnolipids and biofilm formation was higher in the RpoN mutant than in the wild-type. In sum, the results indicated that RpoN had direct and profound effects on QS and T6SS, which provides new cues to better understand the detailed regulatory networks of virulence.
2018-06-30 | GSE110445 | GEO
Project description:The RpoN-RpoS alternative sigma factor pathway is essential for key adaptive responses by Borrelia burgdorferi, particularly those involved in the infection of a mammalian host. A putative response regulator, Rrp2, ostensibly is required for activation of the RpoN-dependent transcription of rpoS. However, questions remain regarding the extent to which the three major constituents of this pathway (Rrp2, RpoN, and RpoS) act interdependently. To assess the functional interplay between Rrp2, RpoN, and RpoS, we employed microarray analyses to compare gene expression levels in rrp2, rpoN, or rpoS mutants of parental strain 297. We identified 98 genes that were similarly regulated by Rrp2, RpoN and RpoS, and an additional 47 genes were determined to be likely regulated by this pathway. The substantial overlap between genes regulated by RpoS and RpoN provides compelling evidence that these two alternative sigma factors form a congruous pathway and that RpoN regulates B. burgdorferi gene expression through RpoS. Although several known B. burgdorferi virulence determinants were regulated by the RpoN-RpoS pathway, a defined function has yet to be ascribed to most of the genes substantially regulated by Rrp2, RpoN and RpoS, therefore providing additional avenues for future research into the genetic determinants contributing to virulence expression by B. burgdorferi. Keywords: gene profiling
2008-09-09 | GSE11284 | GEO
Project description:The RpoN-RpoS alternative sigma factor pathway is essential for key adaptive responses by Borrelia burgdorferi, particularly those involved in the infection of a mammalian host. A putative response regulator, Rrp2, ostensibly is required for activation of the RpoN-dependent transcription of rpoS. However, questions remain regarding the extent to which the three major constituents of this pathway (Rrp2, RpoN, and RpoS) act interdependently. To assess the functional interplay between Rrp2, RpoN, and RpoS, we employed microarray analyses to compare gene expression levels in rrp2, rpoN, or rpoS mutants of parental strain 297. We identified 98 genes that were similarly regulated by Rrp2, RpoN and RpoS, and an additional 47 genes were determined to be likely regulated by this pathway. The substantial overlap between genes regulated by RpoS and RpoN provides compelling evidence that these two alternative sigma factors form a congruous pathway and that RpoN regulates B. burgdorferi gene expression through RpoS. Although several known B. burgdorferi virulence determinants were regulated by the RpoN-RpoS pathway, a defined function has yet to be ascribed to most of the genes substantially regulated by Rrp2, RpoN and RpoS, therefore providing additional avenues for future research into the genetic determinants contributing to virulence expression by B. burgdorferi. Keywords: gene profiling 297 (wt) vs rpoS mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rpoN mutant: 5 slides, 10 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rrp2 mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 5A18 (wt) vs XY424.3 (rrp2 mutant): 5 slides, 10 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rpoS mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rpoN mutant: 5 slides, 10 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rrp2 mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 5A18 (wt) vs XY424.3 (rrp2 mutant): 5 slides, 10 hybridizations (including dyeswaps), three biological replicates
2008-09-09 | E-GEOD-11284 | biostudies-arrayexpress
Project description:comparison of total RNA profiles obtained from wt and rpoN mutant strains in presence of the dctDAAA peptide and chIP/chip experiments to define rpoN targeted DNA segments
2010-12-07 | GSE25849 | GEO
Project description:Experiment conducted to investigate the genetic factors associated with variable and heterogeneous non-planktonic in a mutant lacking rpoN unique to CFT073 bacteria. The aim was to try to understand why RpoN suppresses this heterogeneity in the wild-type during colony growth, but also asses why this phenotype does not occur in other pathogenic strains by also sequencing transcripts from EHEC EDL933. The rpoN mutant strains was complemented with plasmid-borne rpoN containing its native promoter to ensure any differences in gene expression could solely be attributed to the absence of rpoN alone.
2022-01-13 | E-MTAB-11288 | biostudies-arrayexpress
Project description:E. faecalis, wildtype, rpoN deletion mutant and rpoN complement strains were grown in colony biofilms on a defined medium with glucose. Gene expression differences were recorded.
2018-08-10 | GSE40237 | GEO
Project description:The bacterial transcription factor RpoN regulates an extensive network of genes whose products are involved in diverse biological functions. We constructed a small peptide termed the RpoN molecular roadblock, which binds to and blocks transcription from RpoN promoters. This RpoN molecular roadblock can be used in any bacterium to obtain information on the RpoN regulon. We expressed the RpoN molecular roadblock in P. aeruginosa PAO1 and used microarrays to identify genes that were differentially transcribed due to the RpoN molecular roadblock.
2012-02-09 | GSE35632 | GEO
Project description:Rearrangement hot spots (Rhs) proteins are members of the broad family of polymorphic toxins. Polymorphic toxins are modular proteins composed of an N-terminal region that specifies their mode of secretion into the medium or into the target cell, a central delivery module and a C-terminal domain that has toxic activity. Here, we structurally and functionally characterize the C-terminal toxic domain of the antibacterial Rhsmain protein, which is delivered by the Type VI secretion system of Salmonella enterica Typhimurium. We show that this domain adopts an ADP-ribosyltransferase fold and inhibits protein synthesis by transferring an ADP-ribose group from NAD+ to the elongation factor EFTu. This modification is specifically placed on the sidechain of the conserved D21 residue located on the P-loop of the EF-Tu G-domain. Finally, we demonstrate that its cognate immunity protein neutralizes Rhsmain C-terminal toxin activity by acting like a lid that closes the catalytic site and traps the NAD+.
2023-03-11 | PXD033100 | Pride
Project description:There is increasing evidence to support a role for sigma factor 54 (RpoN) in the regulation of stress resistance factors and protein secretion systems important to bacterial transmission and pathogenesis. In enterohemorrhagic E. coli O157:H7, acid resistance and type III secretion are essential determinants of gastric passage and colonization. This study thus described the transcriptome of an rpoN null strain of E. coli O157:H7 (EcJR-8) to determine the influence of RpoN on virulence and stress resistance gene regulation, and further explored its contribution to glutamate-dependent acid resistance (GDAR). Inactivation of rpoN resulted in the growth phase-dependent, differential expression of 104 genes. This included type III secretion structural and regulatory genes encoded on the locus of enterocyte effacement (LEE), as well as GDAR genes gadA, gadBC and gadE. Upregulation of gad transcript levels in EcJR-8 during logarithmic growth correlated with increased GDAR and survival in a model stomach. Acid susceptibility was reconstituted in EcJR-8 complemented in trans with wild-type rpoN. Acid resistance in EcJR-8 was dependent on exogenous glutamate, gadE and rpoS, but was independent of hns. Results also suggest that GDAR may be controlled by RpoN at multiple regulatory levels. This study supports the hypothesis that RpoN is an important regulator of virulence and stress resistance factors in E. coli O157:H7, and is the first to examine the mechanism by which it represses GDAR.
2009-08-08 | GSE17467 | GEO