Host response to plasmid replication and maintenance
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE298911 | GEO | 2025/06/04
REPOSITORIES: GEO
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Project description:Many species of pathogenic bacteria harbor critical plasmid-encoded virulence factors, and yet the regulation of plasmid replication is often poorly understood despite playing key role in plasmid-encoded gene expression. Human pathogenic Yersinia, including the plague agent Yersinia. pestis and its close relative Y. pseudotuberculosis, require the type III secretion system (T3SS) virulence factor to subvert host defense mechanisms and colonize host tissues. The Yersinia T3SS is encoded on the IncFII plasmid for Yersinia virulence (pYV). Several layers of gene regulation enables a large increase in expression of Yersinia T3SS genes at mammalian body temperature. Surprisingly, T3SS expression is also controlled at the level of gene dosage. The number of pYV molecules relative to the number of chromosomes per cell, referred to as plasmid copy number, increases with temperature. The ability to increase and maintain elevated pYV plasmid copy number, and therefore T3SS gene dosage, at 37˚C is important for Yersinia virulence. In addition, pYV is highly stable in Yersinia at all temperatures, despite being dispensable for growth outside the host. Yet how Yersinia reinforces elevated plasmid replication and plasmid stability remains unclear. In this study, we show that the chromosomal gene pcnB encoding the polyadenylase PAP I is required for regulation of pYV plasmid copy number (PCN), maintenance of pYV in the bacterial population outside the host, robust T3SS activity, and Yersinia virulence in a mouse infection model. Likewise, pcnB/PAP I is also required for robust expression of the Shigella flexneri virulence plasmid-encoded T3SS that, similar to Yersinia, is encoded on a virulence plasmid whose replication is regulated by sRNA. Furthermore, Yersinia and Shigella pcnB/PAP I is required for maintaining normal PCN of model antimicrobial resistance (AMR) plasmids whose replication is regulated by sRNA, thereby increasing antibiotic resistance by ten-fold. These data suggest that pcnB/PAP I contributes to the spread and stabilization of sRNA-regulated virulence and AMR plasmids in bacterial pathogens, and is essential in maintaining the gene dosage required to mediate plasmid-encoded traits. Importantly pcnB/PAP I has been bioinformatically identified in many species of bacteria despite being studied in only a few species to date. Our work highlights the potential importance of pcnB/PAP I in antibiotic resistance, and shows for the first time that pcnB/PAP I reinforces PCN andpromotes virulence plasmid stability in natural pathogenic hosts with a direct impact on bacterial virulence.
2025-03-20 | GSE292107 | GEO
Project description:Plasmids are extrachromosomal genetic elements commonly found in bacteria. Plasmids are known to fuel bacterial evolution through horizontal gene transfer (HGT), but recent analyses indicate that they can also promote intragenomic adaptations. However, the role of plasmids as catalysts of bacterial evolution beyond HGT remains poorly explored. In this study, we investigate the impact of a widespread conjugative plasmid, pOXA-48, on the evolution of various multidrug-resistant clinical enterobacteria. Combining experimental and within-patient evolution analyses, we unveil that plasmid pOXA-48 promotes bacterial evolution through the transposition of plasmid-encoded IS1 elements. Specifically, IS1-mediated gene inactivations expedite the adaptation rate of clinical strains in vitro and foster within-patient adaptation in the gut. We decipher the mechanism underlying the plasmid-mediated surge in IS1 transposition, revealing a negative feedback loop regulated by the genomic copy number of IS1. Given the overrepresentation of IS elements in bacterial plasmids, our findings propose that plasmid-mediated IS transposition represents a crucial mechanism for swift bacterial adaptation.
2024-07-16 | GSE255663 | GEO
Project description:<p>Gut environments harbour dense microbial ecosystems in which plasmids are widely distributed. Plasmids facilitate the exchange of genetic material among microorganisms while enabling the transfer of a diverse array of accessory functions. However, their precise impact on microbial community composition and function remains largely unexplored. Here we identify a prevalent bacterial toxin and a plasmid-encoded resistance mechanism that mediates the interaction between Lactobacilli and Enterococci. This plasmid is widespread across ecosystems, including the rumen and human gut microbiota. Biochemical characterization of the plasmid revealed a defence mechanism against reuterin, a toxin produced by various gut microbes, such as Limosilactobacillus reuteri. Using a targeted metabolomic approach, we find reuterin to be prevalent across rumen ecosystems with impacts on microbial community structure. Enterococcus strains carrying the protective plasmid were isolated and their interactions with L. reuteri, the toxin producer, were studied in vitro. Interestingly, we found that by conferring resistance against reuterin, the plasmid mediates metabolic exchange between the defending and the attacking microbial species, resulting in a beneficial relationship or mutualism. Hence, we reveal here an ecological role for a plasmid-coded defence system in mediating a beneficial interaction. </p>
2023-08-10 | MTBLS7248 | MetaboLights
Project description:Adeno-associated viral vectors (AAV) are a leading delivery system for gene therapy in animal models and humans. With several FDA-approved AAV gene therapies on the market, issues related to vector manufacturing have become increasingly important. In this study, we focused on potentially toxic DNA contaminants that can arise from AAV proviral plasmids, the raw materials required for manufacturing recombinant AAV in eukaryotic cells. Typical AAV proviral plasmids are circular DNAs containing a therapeutic gene cassette flanked by natural AAV inverted terminal repeat (ITR) sequences, and a plasmid backbone carrying prokaryotic sequences required for plasmid replication and selection in bacteria. While the majority of AAV particles package the intended therapeutic payload, some capsids instead package the bacterial sequences located on the proviral plasmid backbone. Since ITR sequences also have promoter activity, potentially toxic bacterial open reading frames can be produced in vivo, thereby representing a safety risk. In this study, we describe a new AAV proviral plasmid for vector manufacturing that (1) significantly decreases cross-packaged bacterial sequences; (2) increases correctly packaged AAV payloads; and (3) blunts ITR-driven transcription of cross-packaged material to avoid expressing potentially toxic bacterial sequences. This system may help improve the safety of AAV vector products.
2024-07-26 | GSE272650 | GEO
Project description:Adeno-associated viral vectors (AAV) are a leading delivery system for gene therapy in animal models and humans. With several FDA-approved AAV gene therapies on the market, issues related to vector manufacturing have become increasingly important. In this study, we focused on potentially toxic DNA contaminants that can arise from AAV proviral plasmids, the raw materials required for manufacturing recombinant AAV in eukaryotic cells. Typical AAV proviral plasmids are circular DNAs containing a therapeutic gene cassette flanked by natural AAV inverted terminal repeat (ITR) sequences, and a plasmid backbone carrying prokaryotic sequences required for plasmid replication and selection in bacteria. While the majority of AAV particles package the intended therapeutic payload, some capsids instead package the bacterial sequences located on the proviral plasmid backbone. Since ITR sequences also have promoter activity, potentially toxic bacterial open reading frames can be produced in vivo, thereby representing a safety risk. In this study, we describe a new AAV proviral plasmid for vector manufacturing that (1) significantly decreases cross-packaged bacterial sequences; (2) increases correctly packaged AAV payloads; and (3) blunts ITR-driven transcription of cross-packaged material to avoid expressing potentially toxic bacterial sequences. This system may help improve the safety of AAV vector products.
2024-07-26 | GSE272649 | GEO
Project description:Plasmid fitness is directed by two orthogonal processes—vertical transfer through cell division and horizontal transfer through conjugation. When considered individually, improvements in either mode of transfer can promote how well a plasmid spreads and persists. Together, however, the metabolic cost of conjugation could create a tradeoff that constrains plasmid evolution. Here we present evidence for the presence, consequences, and molecular basis of a conjugation-growth tradeoff across 40 plasmids derived from clinical E. coli pathogens. We discover that most plasmids operate below a conjugation efficiency threshold for major growth effects, indicating strong natural selection for vertical transfer. Below this threshold, E. coli demonstrates a remarkable growth tolerance to over four orders of magnitude change in conjugation efficiency. This tolerance fades as nutrients become scarce and horizontal transfer attracts a greater share of host resources. Our results provide insight into evolutionary constraints directing plasmid fitness and strategies to combat the spread of antibiotic resistance.
2022-12-23 | GSE219270 | GEO
Project description:L. lactis NIAI712 carries five different plasmids, including an 8.7-kb plasmid designated pAG6. In this study, genome-wide expression profiles of the pAG6-cured variant was compared to the wild-type strain.
2013-08-31 | GSE48143 | GEO
Project description:The model organism Dinoroseobacter shibae and many other marine Rhodobacterales (Roseobacteraceae, Alphaproteobacteria) are characterized by a multipartite genome organization. Here we show that the original isolate (Dshi-6) contained six extrachromosomal replicons (ECRs), whereas the strain deposited at the DSMZ (Dshi-5) lacked a 102 kb plasmid. To determine the role of the sixth plasmid, we investigated the genomic and physiological differences between the two strains. Therefore, both genomes were (re-)sequenced and gene expression, growth and substrate utilization were examined. For comparison, we included additional plasmid-cured strains in the genome analysis. In the Dshi-6 population, the conjugative 102 kb RepABC-9 plasmid was only present in about 50 % of the cells, irrespective of its experimentally validated stability. In the presence of the sixth plasmid, copy number changes of other ECRs, in particular a decrease of the 86 kb plasmid, were observed. The most conspicuous finding was the strong influence of plasmids on the chromosomal gene expression, especially the repression of the CtrA regulon and the activation of the denitrification gene cluster. The expression is inversely controlled either by the presence of the 102 kb or the absence of the 86 kb plasmid. We identified global regulatory genes on both plasmids, i.e. a sigma 70 factor, and a quorum sensing synthase, that might be responsible for these major changes. The tremendous effects challenge the current understanding of the relevance of volatile plasmids not only for the original host, but also for new recipients after conjugation.
2022-03-13 | GSE198318 | GEO
Project description:Bacterial defence systems are tightly regulated to avoid autoimmunity. In Type I restriction-modification (R-M) systems, a specific mechanism called restriction alleviation (RA) controls the activity of the restriction module. In the case of the Escherichia coli Type I R-M system EcoKI, RA proceeds through ClpXP-mediated proteolysis of restriction complexes bound to non-methylated sites that appear after replication or reparation of host DNA. Here, we show that RA is also induced in the presence of plasmids carrying EcoKI recognition sites, a phenomenon we refer to as plasmid-induced RA. Further, we show that the anti-restriction behavior of plasmid-borne non-conjugative transposons such as Tn5053, previously attributed to their ardD loci, is due to plasmid-induced RA. Plasmids carrying both EcoKI and Chi sites induce RA in RecA- and RecBCD-dependent manner. However, inactivation of both RecA and RecBCD restores RA, indicating that there exists an alternative, RecA-independent, homologous recombination pathway that is blocked in the presence of RecBCD. Indeed, plasmid-induced RA in a RecBCD-deficient background does not depend on the presence of Chi sites. We propose that processing of random dsDNA breaks in plasmid DNA via homologous recombination generates non-methylated EcoKI sites, which attract EcoKI restriction complexes channeling them for ClpXP-mediated proteolysis.
2024-06-23 | PXD050621 | Pride
Project description:Conjugative plasmids are the main vehicle for the horizontal spread of antimicrobial resistance (AMR). Although AMR plasmids provide advantages to their hosts under antibiotic pressure, they can also disrupt the cell’s regulatory network, impacting the fitness of their hosts. Despite the importance of plasmid-bacteria interactions on the evolution of AMR, the effects of plasmid carriage on host physiology has remained underexplored, and most studies have focused on model bacteria and plasmids that lack clinical relevance. Here, we analyzed the transcriptional response of 11 clinical enterobacterial strains (2 Escherichia coli, 1 Citrobacter freundii and 8 Klebsiella spp.) and the laboratory-adapted E. coli MG1655 to carriage of pOXA-48, one of the most widely spread carbapenem-resistance plasmids. Our analyses revealed that pOXA-48 produces variable responses on their hosts, but commonly affects processes related to metabolism, transport, response to stimulus, cellular organization and motility. More notably, the presence of pOXA-48 caused an increase in the expression of a small chromosomal operon of unknown function in Klebsiella spp. and C. freundii, which is not present in E. coli. Phylogenetic analysis suggested that this operon has been horizontally mobilized across different Proteobacteria species. We demonstrate that a pOXA-48-encoded LysR transcriptional regulator controls the expression of the operon in Klebsiella spp. and C. freundii. In summary, our results highlight a crosstalk between pOXA-48 and the chromosome of its natural hosts.
2024-07-16 | GSE269852 | GEO