1
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Khachaturyan M, Santer M, Reusch TBH, Dagan T. Heteroplasmy Is Rare in Plant Mitochondria Compared with Plastids despite Similar Mutation Rates. Mol Biol Evol 2024; 41:msae135. [PMID: 38934796 PMCID: PMC11245704 DOI: 10.1093/molbev/msae135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 06/11/2024] [Accepted: 06/20/2024] [Indexed: 06/28/2024] Open
Abstract
Plant cells harbor two membrane-bound organelles containing their own genetic material-plastids and mitochondria. Although the two organelles coexist and coevolve within the same plant cells, they differ in genome copy number, intracellular organization, and mode of segregation. How these attributes affect the time to fixation or, conversely, loss of neutral alleles is currently unresolved. Here, we show that mitochondria and plastids share the same mutation rate, yet plastid alleles remain in a heteroplasmic state significantly longer compared with mitochondrial alleles. By analyzing genetic variants across populations of the marine flowering plant Zostera marina and simulating organelle allele dynamics, we examine the determinants of allele segregation and allele fixation. Our results suggest that the bottlenecks on the cell population, e.g. during branching or seeding, and stratification of the meristematic tissue are important determinants of mitochondrial allele dynamics. Furthermore, we suggest that the prolonged plastid allele dynamics are due to a yet unknown active plastid partition mechanism. The dissimilarity between plastid and mitochondrial novel allele fixation at different levels of organization may manifest in differences in adaptation processes. Our study uncovers fundamental principles of organelle population genetics that are essential for further investigations of long-term evolution and molecular dating of divergence events.
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Affiliation(s)
- Marina Khachaturyan
- Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Institute of General Microbiology, University of Kiel, Kiel, Germany
| | - Mario Santer
- Institute of General Microbiology, University of Kiel, Kiel, Germany
| | - Thorsten B H Reusch
- Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Tal Dagan
- Institute of General Microbiology, University of Kiel, Kiel, Germany
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2
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Murányi G, Szabó M, Acsai K, Kiss J. Two birds with one stone: SGI1 can stabilize itself and expel the IncC helper by hijacking the plasmid parABS system. Nucleic Acids Res 2024; 52:2498-2518. [PMID: 38300764 PMCID: PMC10954446 DOI: 10.1093/nar/gkae050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/11/2024] [Accepted: 01/16/2024] [Indexed: 02/03/2024] Open
Abstract
The SGI1 family integrative mobilizable elements, which are efficient agents in distribution of multidrug resistance in Gammaproteobacteria, have a complex, parasitic relationship with their IncC conjugative helper plasmids. Besides exploiting the transfer apparatus, SGI1 also hijacks IncC plasmid control mechanisms to time its own excision, replication and expression of self-encoded T4SS components, which provides advantages for SGI1 over its helpers in conjugal transfer and stable maintenance. Furthermore, SGI1 destabilizes its helpers in an unknown, replication-dependent way when they are concomitantly present in the same host. Here we report how SGI1 exploits the helper plasmid partitioning system to displace the plasmid and simultaneously increase its own stability. We show that SGI1 carries two copies of sequences mimicking the parS sites of IncC plasmids. These parS-like elements bind the ParB protein encoded by the plasmid and increase SGI1 stability by utilizing the parABS system of the plasmid for its own partitioning, through which SGI1 also destabilizes the helper plasmid. Furthermore, SGI1 expresses a small protein, Sci, which significantly strengthens this plasmid-destabilizing effect, as well as SGI1 maintenance. The plasmid-induced replication of SGI1 results in an increased copy-number of parS-like sequences and Sci expression leading to strong incompatibility with the helper plasmid.
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Affiliation(s)
- Gábor Murányi
- Department of Microbiology and Applied Biotechnology, Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, H2100 Hungary
| | - Mónika Szabó
- Department of Microbiology and Applied Biotechnology, Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, H2100 Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Gödöllő, H2100 Hungary
| | - Károly Acsai
- Ceva Animal Health, Ceva-Phylaxia, Budapest, H1107 Hungary
| | - János Kiss
- Department of Microbiology and Applied Biotechnology, Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, H2100 Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Gödöllő, H2100 Hungary
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3
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Cornet F, Blanchais C, Dusfour-Castan R, Meunier A, Quebre V, Sekkouri Alaoui H, Boudsoq F, Campos M, Crozat E, Guynet C, Pasta F, Rousseau P, Ton Hoang B, Bouet JY. DNA Segregation in Enterobacteria. EcoSal Plus 2023; 11:eesp00382020. [PMID: 37220081 PMCID: PMC10729935 DOI: 10.1128/ecosalplus.esp-0038-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 04/13/2023] [Indexed: 01/28/2024]
Abstract
DNA segregation ensures that cell offspring receive at least one copy of each DNA molecule, or replicon, after their replication. This important cellular process includes different phases leading to the physical separation of the replicons and their movement toward the future daughter cells. Here, we review these phases and processes in enterobacteria with emphasis on the molecular mechanisms at play and their controls.
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Affiliation(s)
- François Cornet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Corentin Blanchais
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Romane Dusfour-Castan
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Alix Meunier
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Valentin Quebre
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Hicham Sekkouri Alaoui
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - François Boudsoq
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Manuel Campos
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Estelle Crozat
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Catherine Guynet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Franck Pasta
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Philippe Rousseau
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Bao Ton Hoang
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Jean-Yves Bouet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
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4
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Tian D, Zhao M, Zheng S, Jiang X, Zhang B. Involvement of Tn3 transposon in formation and transmission of hypervirulent and carbapenem-resistant Klebsiella pneumoniae. Microbiol Spectr 2023; 11:e0303823. [PMID: 37982629 PMCID: PMC10714771 DOI: 10.1128/spectrum.03038-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/14/2023] [Indexed: 11/21/2023] Open
Abstract
IMPORTANCE Carbapenem-resistant Klebsiella pneumoniae (CRKP) is resistant to most common antibiotics, becoming the most important and prevalent nosocomial opportunity pathogen. Besides, K. pneumoniae can also cause severe community-acquired infections, such as primary liver abscess and endophthalmitis. These pathogens are commonly referred to as hvKp. CRKP and hvKp have evolved separately, each occupying its own clonal lineage and exhibiting a variety of properties. Our study provides important insights into the evolutionary events related to the arousal of virulence and drug resistance in K. pneumoniae through plasmid transmission, mediated by Tn3 transposon. Our study also provides evidence that multiple mechanisms contribute to the successful transfer of non-conjugative virulence plasmid, and the involvement of transposons enhances the efficiency. A good knowledge of its transmission mechanisms is fundamental to finding effective strategies to combat these threatening pathogens. Transposons are widely present in bacteria, spreading resistance and virulence genes between the environment and humans. Therefore, emerging transposon-mediated hypervirulent and carbapenem-resistant pathogens should be highly valued.
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Affiliation(s)
- Dongxing Tian
- Department of Clinical Laboratory, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, China
- Postdoctoral Mobile Station of Shandong University of Traditional Chinese Medicine, Jinan, Shandong Province, China
| | - Mingqi Zhao
- Affiliated Hospital of Jining Medical University, Jining, Shandong Province, China
| | - Sasa Zheng
- Department of Oncology, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, China
| | - Xiaofei Jiang
- Department of Clinical Laboratory, Huashan Hospital, Fudan University, Shanghai, China
| | - Bin Zhang
- Department of Clinical Laboratory, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, China
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5
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Weisberg AJ, Chang JH. Mobile Genetic Element Flexibility as an Underlying Principle to Bacterial Evolution. Annu Rev Microbiol 2023; 77:603-624. [PMID: 37437216 DOI: 10.1146/annurev-micro-032521-022006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Mobile genetic elements are key to the evolution of bacteria and traits that affect host and ecosystem health. Here, we use a framework of a hierarchical and modular system that scales from genes to populations to synthesize recent findings on mobile genetic elements (MGEs) of bacteria. Doing so highlights the role that emergent properties of flexibility, robustness, and genetic capacitance of MGEs have on the evolution of bacteria. Some of their traits can be stored, shared, and diversified across different MGEs, taxa of bacteria, and time. Collectively, these properties contribute to maintaining functionality against perturbations while allowing changes to accumulate in order to diversify and give rise to new traits. These properties of MGEs have long challenged our abilities to study them. Implementation of new technologies and strategies allows for MGEs to be analyzed in new and powerful ways.
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Affiliation(s)
- Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA;
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA;
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6
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Kazi TA, Mukhopadhyay BC, Mandal S, Biswas SR. Molecular characterization of five novel plasmids from Enterococcus italicus SD1 isolated from fermented milk: An insight into understanding plasmid incompatibility. Gene 2023; 856:147154. [PMID: 36574936 DOI: 10.1016/j.gene.2022.147154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/15/2022] [Accepted: 12/23/2022] [Indexed: 12/25/2022]
Abstract
Enterococcal plasmids have attracted considerable interest because of their indispensable role in the pathogenesis and dissemination of multidrug-resistance. In this work, five novel plasmids pSRB2, pSRB3, pSRB4, pSRB5 and pSRB7 have been identified and characterised, coexisting in Eneterococcus italicus SD1 from fermented milk. The plasmids pSRB2, pSRB3 and pSRB5 were found to replicate via theta mode of replication while pSRB4 and pSRB7 were rolling-circle plasmids. Comparative analysis of SD1-plasmids dictated that the plasmids are mosaic with novel architecture. Plasmids pSRB2 and pSRB5 are comprised of a typical iteron-based class-A theta type origin of replication, whereas pSRB3 has a Class-D theta type replication origin like pAMβ1. The plasmids pSRB4 and pSRB7 shared similar ori as in pWV01. The SD1 class-A theta type plasmids shared significant homology between their replication proteins with differences in their DNA-binding domain and comprises of distinct iterons. The differences in their iterons and replication proteins restricts the "handcuff" formation for inhibition of plasmid replication, rendering to their compatibility to coexist. Similarly, for SD1 rolling circle plasmids the differences in the replication protein binding site in the origin and the replication protein supports their coexistence by inhibiting the crosstalk between the origins and replication proteins. The phylogenetic tree of their replication proteins revealed their distant kinship. The results indicate that the identified plasmids are unique to E. italicus SD1, providing further opportunities to study their utility in designing multiple gene expression systems for the simultaneous production of proteins in enterococci with the renewed concept of plasmid incompatibility.
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Affiliation(s)
- Tawsif Ahmed Kazi
- Department of Botany, Visva-Bharati University, Santiniketan 731235, West Bengal, India
| | | | - Sukhendu Mandal
- Laboratory of Molecular Bacteriology, Department of Microbiology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, India
| | - Swadesh Ranjan Biswas
- Department of Botany, Visva-Bharati University, Santiniketan 731235, West Bengal, India.
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7
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Pilosof S. Conceptualizing microbe-plasmid communities as complex adaptive systems. Trends Microbiol 2023:S0966-842X(23)00025-2. [PMID: 36822952 DOI: 10.1016/j.tim.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/29/2022] [Accepted: 01/23/2023] [Indexed: 02/24/2023]
Abstract
Plasmids shape microbial communities' diversity, structure, and function. Nevertheless, we lack a mechanistic understanding of how community structure and dynamics emerge from local microbe-plasmid interactions and coevolution. Addressing this gap is challenging because multiple processes operate simultaneously at multiple levels of organization. For example, immunity operates between a plasmid and a cell, but incompatibility mechanisms regulate coexistence between plasmids. Conceptualizing microbe-plasmid communities as complex adaptive systems is a promising approach to overcoming these challenges. I illustrate how agent-based evolutionary modeling, extended by network analysis, can be used to quantify the relative importance of local processes governing community dynamics. These theoretical developments can advance our understanding of plasmid ecology and evolution, especially when combined with empirical data.
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Affiliation(s)
- Shai Pilosof
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel.
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8
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The Specificity of ParR Binding Determines the Incompatibility of Conjugative Plasmids in Clostridium perfringens. mBio 2022; 13:e0135622. [PMID: 35726914 PMCID: PMC9426499 DOI: 10.1128/mbio.01356-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Plasmids that encode the same replication machinery are generally unable to coexist in the same bacterial cell. However, Clostridium perfringens strains often carry multiple conjugative toxin or antibiotic resistance plasmids that are closely related and encode similar Rep proteins. In many bacteria, plasmid partitioning upon cell division involves a ParMRC system; in C. perfringens plasmids, there are approximately 10 different ParMRC families, with significant differences in amino acid sequences between each ParM family (15% to 54% identity). Since plasmids carrying genes belonging to the same ParMRC family are not observed in the same strain, these families appear to represent the basis for plasmid compatibility in C. perfringens. To understand this process, we examined the key recognition steps between ParR DNA-binding proteins and their parC binding sites. The ParR proteins bound to sequences within a parC site from the same ParMRC family but could not interact with a parC site from a different ParMRC family. These data provide evidence that compatibility of the conjugative toxin plasmids of C. perfringens is mediated by their parMRC-like partitioning systems. This process provides a selective advantage by enabling the host bacterium to maintain separate plasmids that encode toxins that are specific for different host targets.
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9
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Coluzzi C, Garcillán-Barcia MP, de la Cruz F, Rocha EPC. Evolution of plasmid mobility: origin and fate of conjugative and non-conjugative plasmids. Mol Biol Evol 2022; 39:6593704. [PMID: 35639760 PMCID: PMC9185392 DOI: 10.1093/molbev/msac115] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Conjugation drives the horizontal transfer of adaptive traits across prokaryotes. One-fourth of the plasmids encode the functions necessary to conjugate autonomously, the others being eventually mobilizable by conjugation. To understand the evolution of plasmid mobility, we studied plasmid size, gene repertoires, and conjugation-related genes. Plasmid gene repertoires were found to vary rapidly in relation to the evolutionary rate of relaxases, for example, most pairs of plasmids with 95% identical relaxases have fewer than 50% of homologs. Among 249 recent transitions of mobility type, we observed a clear excess of plasmids losing the capacity to conjugate. These transitions are associated with even greater changes in gene repertoires, possibly mediated by transposable elements, including pseudogenization of the conjugation locus, exchange of replicases reducing the problem of incompatibility, and extensive loss of other genes. At the microevolutionary scale of plasmid taxonomy, transitions of mobility type sometimes result in the creation of novel taxonomic units. Interestingly, most transitions from conjugative to mobilizable plasmids seem to be lost in the long term. This suggests a source-sink dynamic, where conjugative plasmids generate nonconjugative plasmids that tend to be poorly adapted and are frequently lost. Still, in some cases, these relaxases seem to have evolved to become efficient at plasmid mobilization in trans, possibly by hijacking multiple conjugative systems. This resulted in specialized relaxases of mobilizable plasmids. In conclusion, the evolution of plasmid mobility is frequent, shapes the patterns of gene flow in bacteria, the dynamics of gene repertoires, and the ecology of plasmids.
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Affiliation(s)
- Charles Coluzzi
- Institut Pasteur, Université de Paris Cité, CNRS, UMR3525, Microbial Evolutionary Genomics, Paris, 75015, France
| | - M Pilar Garcillán-Barcia
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, C/Albert Einstein 22, 39011, Santander, Spain
| | - Fernando de la Cruz
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, C/Albert Einstein 22, 39011, Santander, Spain
| | - Eduardo P C Rocha
- Institut Pasteur, Université de Paris Cité, CNRS, UMR3525, Microbial Evolutionary Genomics, Paris, 75015, France
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10
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Examination of Rickettsial Host Range for Shuttle Vectors Based on dnaA and parA Genes from the pRM Plasmid of Rickettsia monacensis. Appl Environ Microbiol 2022; 88:e0021022. [PMID: 35323021 PMCID: PMC9004397 DOI: 10.1128/aem.00210-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The genus Rickettsia encompasses a diverse group of obligate intracellular bacteria that are highly virulent disease agents of mankind as well as symbionts of arthropods. Native plasmids of Rickettsia amblyommatis (AaR/SC) have been used as models to construct shuttle vectors for genetic manipulation of several Rickettsia species. Here, we report on the isolation of the complete plasmid (pRM658B) from Rickettsia monacensis IrR/Munich mutant Rmona658B and the construction of shuttle vectors based on pRM. To identify regions essential for replication, we made vectors containing the dnaA and parA genes of pRM with various portions of the region surrounding these genes and a selection reporter cassette conferring resistance to spectinomycin and expression of green fluorescent protein. Rickettsia amblyommatis (AaR/SC), R. monacensis (IrR/Munich), Rickettsia bellii (RML 369-C), Rickettsia parkeri (Tate’s Hell), and Rickettsia montanensis (M5/6) were successfully transformed with shuttle vectors containing pRM parA and dnaA. PCR assays targeting pRM regions not included in the vectors revealed that native pRM was retained in R. monacensis transformants. Determination of native pRM copy number using a plasmid-carried gene (RM_p5) in comparison to chromosomally carried gltA indicated reduced copy numbers in R. monacensis transformants. In transformed R. monacensis strains, native pRM and shuttle vectors with homologous parA and dnaA formed native plasmid-shuttle vector complexes. These studies provide insight on the maintenance of plasmids and shuttle vectors in rickettsiae. IMPORTANCERickettsia spp. are found in a diverse array of organisms, from ticks, mites, and fleas to leeches and insects. Many are not pathogenic, but others, such as Rickettsia rickettsii and Rickettsia prowazeckii, can cause severe illness or death. Plasmids are found in a large percentage of nonpathogenic rickettsiae, but not in species that cause severe disease. Studying these plasmids can reveal their role in the biology of these bacteria, as well as the molecular mechanism whereby they are maintained and replicate in rickettsiae. Here, we describe a new series of shuttle plasmids for the transformation of rickettsiae based on parA and dnaA sequences of plasmid pRM from Rickettsia monacensis. These shuttle vectors support transformation of diverse rickettsiae, including the native host of pRM, and are useful for investigating genetic determinants that govern rickettsial virulence or their ability to function as symbionts.
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11
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Igler C, Huisman JS, Siedentop B, Bonhoeffer S, Lehtinen S. Plasmid co-infection: linking biological mechanisms to ecological and evolutionary dynamics. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200478. [PMID: 34839701 PMCID: PMC8628072 DOI: 10.1098/rstb.2020.0478] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/09/2021] [Indexed: 12/27/2022] Open
Abstract
As infectious agents of bacteria and vehicles of horizontal gene transfer, plasmids play a key role in bacterial ecology and evolution. Plasmid dynamics are shaped not only by plasmid-host interactions but also by ecological interactions between plasmid variants. These interactions are complex: plasmids can co-infect the same cell and the consequences for the co-resident plasmid can be either beneficial or detrimental. Many of the biological processes that govern plasmid co-infection-from systems that exclude infection by other plasmids to interactions in the regulation of plasmid copy number-are well characterized at a mechanistic level. Modelling plays a central role in translating such mechanistic insights into predictions about plasmid dynamics and the impact of these dynamics on bacterial evolution. Theoretical work in evolutionary epidemiology has shown that formulating models of co-infection is not trivial, as some modelling choices can introduce unintended ecological assumptions. Here, we review how the biological processes that govern co-infection can be represented in a mathematical model, discuss potential modelling pitfalls, and analyse this model to provide general insights into how co-infection impacts ecological and evolutionary outcomes. In particular, we demonstrate how beneficial and detrimental effects of co-infection give rise to frequency-dependent selection on plasmid variants. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.
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Affiliation(s)
- Claudia Igler
- Institute of Integrative Biology, Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland
| | - Jana S. Huisman
- Institute of Integrative Biology, Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Berit Siedentop
- Institute of Integrative Biology, Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland
| | - Sebastian Bonhoeffer
- Institute of Integrative Biology, Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland
| | - Sonja Lehtinen
- Institute of Integrative Biology, Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland
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12
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Oluwadare M, Lee MD, Grim CJ, Lipp EK, Cheng Y, Maurer JJ. The Role of the Salmonella spvB IncF Plasmid and Its Resident Entry Exclusion Gene traS on Plasmid Exclusion. Front Microbiol 2020; 11:949. [PMID: 32499773 PMCID: PMC7242723 DOI: 10.3389/fmicb.2020.00949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/21/2020] [Indexed: 11/30/2022] Open
Abstract
Salmonella enterica cause significant illnesses worldwide. There has been a marked increase in resistance to fluoroquinolones and β-lactams/cephalosporins, antibiotics commonly used to treat salmonellosis. However, S. enterica serovars vary in their resistance to these and other antibiotics. The systemic virulence of some Salmonella serovars is due to a low copy number, IncF plasmid (65-100 kb) that contains the ADP-ribosylating toxin, SpvB. This virulence plasmid is present in only nine Salmonella serovars. It is possible that the spvB-virulence plasmid excludes other plasmids and may explain why antibiotic resistance is slow to develop in certain Salmonella serovars such as S. Enteritidis. The distribution of plasmid entry exclusion genes traS/traT and traY/excA are variable in Salmonella IncF and IncI plasmids, respectively and may account for differences in emergent antimicrobial resistance for some Salmonella serovars. The goal of this study is to determine the contribution of the Salmonella spvB-virulence plasmid in F-plasmid exclusion. From conjugation experiments, S. Typhimurium exhibited lower conjugation frequency with incFI and incFII plasmids when the spvB-virulence plasmid is present. Furthermore, introduction of cloned incFI traS into a "plasmidless" S. Typhimurium LT2 strain and Escherichia coli DH5α excluded incFI plasmid. However, deletion of the virulence plasmid traS did not affect plasmid exclusion significantly compared to a spvB control deletion. In addition, differences in F plasmid conjugation in natural Salmonella isolates did not correlate with IncF or SpvB-virulence plasmid genotype. There appear to be other plasmid or chromosomal genes at play in plasmid exclusion that may be responsible for the slow development of antibiotic resistance in certain serovars.
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Affiliation(s)
- Mopelola Oluwadare
- Department of Population Health, University of Georgia, Athens, GA, United States
| | - Margie D. Lee
- Department of Population Health, University of Georgia, Athens, GA, United States
- Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Christopher J. Grim
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, United States
| | - Erin K. Lipp
- Department of Environmental Health Science, University of Georgia, Athens, GA, United States
| | - Ying Cheng
- Department of Population Health, University of Georgia, Athens, GA, United States
| | - John J. Maurer
- Department of Population Health, University of Georgia, Athens, GA, United States
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
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13
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Abstract
Plasmids are ubiquitous in the microbial world and have been identified in almost all species of bacteria that have been examined. Their localization inside the bacterial cell has been examined for about two decades; typically, they are not randomly distributed, and their positioning depends on copy number and their mode of segregation. Low-copy-number plasmids promote their own stable inheritance in their bacterial hosts by encoding active partition systems, which ensure that copies are positioned in both halves of a dividing cell. High-copy plasmids rely on passive diffusion of some copies, but many remain clustered together in the nucleoid-free regions of the cell. Here we review plasmid localization and partition (Par) systems, with particular emphasis on plasmids from Enterobacteriaceae and on recent results describing the in vivo localization properties and molecular mechanisms of each system. Partition systems also cause plasmid incompatibility such that distinct plasmids (with different replicons) with the same Par system cannot be stably maintained in the same cells. We discuss how partition-mediated incompatibility is a consequence of the partition mechanism.
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14
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Yano H, Shintani M, Tomita M, Suzuki H, Oshima T. Reconsidering plasmid maintenance factors for computational plasmid design. Comput Struct Biotechnol J 2018; 17:70-81. [PMID: 30619542 PMCID: PMC6312765 DOI: 10.1016/j.csbj.2018.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 12/08/2018] [Accepted: 12/09/2018] [Indexed: 12/18/2022] Open
Abstract
Plasmids are genetic parasites of microorganisms. The genomes of naturally occurring plasmids are expected to be polished via natural selection to achieve long-term persistence in the microbial cell population. However, plasmid genomes are extremely diverse, and the rules governing plasmid genomes are not fully understood. Therefore, computationally designing plasmid genomes optimized for model and nonmodel organisms remains challenging. Here, we summarize current knowledge of the plasmid genome organization and the factors that can affect plasmid persistence, with the aim of constructing synthetic plasmids for use in gram-negative bacteria. Then, we introduce publicly available resources, plasmid data, and bioinformatics tools that are useful for computational plasmid design.
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Affiliation(s)
- Hirokazu Yano
- Graduate School of Life Sciences, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Masaki Shintani
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, 3-5-1, Hamamatsu 432-8561, Japan
- Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, 3-5-1, Hamamatsu 432-8561, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, 14-1, Baba-cho, Tsuruoka, Yamagata 997-0035, Japan
- Faculty of Environment and Information Studies, Keio University, 5322, Endo, Fujisawa, Kanagawa 252-0882, Japan
| | - Haruo Suzuki
- Institute for Advanced Biosciences, Keio University, 14-1, Baba-cho, Tsuruoka, Yamagata 997-0035, Japan
- Faculty of Environment and Information Studies, Keio University, 5322, Endo, Fujisawa, Kanagawa 252-0882, Japan
| | - Taku Oshima
- Department of Biotechnology, Toyama Prefectural University, 5180, Kurokawa, Imizu, Toyama 939-0398, Japan
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15
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Watts TD, Johanesen PA, Lyras D, Rood JI, Adams V. Evidence that compatibility of closely related replicons in Clostridium perfringens depends on linkage to parMRC-like partitioning systems of different subfamilies. Plasmid 2017; 91:68-75. [PMID: 28390955 DOI: 10.1016/j.plasmid.2017.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 11/17/2022]
Abstract
Clostridium perfringens produces an extensive repertoire of toxins and extracellular enzymes, many of which are intimately involved in the progression of disease and are encoded by genes on conjugative plasmids. In addition, many C. perfringens strains can carry up to five of these conjugative toxin or antimicrobial resistance plasmids, each of which has a similar 35kb backbone. This conserved backbone includes the tcp conjugation locus and the central control region (CCR), which encodes genes involved in plasmid regulation, replication and partitioning, including a parMRC partitioning locus. Most conjugative plasmids in C. perfringens have a conserved replication protein, raising questions as to how multiple, closely related plasmids are maintained within a single strain. Bioinformatics analysis has highlighted the presence of at least 10 different parMRC partitioning system families (parMRCA-J) in these plasmids, with differences in amino acid sequence identity between each ParM family ranging from 15% to 54%. No two plasmids that encode genes belonging to the same partitioning family have been observed in a single strain, suggesting that these families represent the basis for plasmid incompatibility. In an attempt to validate the proposed parMRC incompatibility groups, genetically marked C. perfringens plasmids encoding identical parMRCC or parMRCD homologues or different combinations of parMRCA, parMRCC and parMRCD family homologues were introduced into a single strain via conjugation. The stability of each plasmid was determined using an incompatibility assay in which the plasmid profile of each strain was monitored over the course of two days in the absence of direct selection. The results showed that plasmids with identical parMRCC or parMRCD homologues were incompatible and could not coexist in the absence of external selection. By contrast, plasmids that encoded different parMRC homologues were compatible and could coexist in the same cell in the absence of selection, with the exception of strains housing parMRCC and parMRCD combinations, which showed a minor incompatibility phenotype. In conclusion, we have provided the first direct evidence of plasmid incompatibility in Clostridium spp. and have shown experimentally that the compatibility of conjugative C. perfringens plasmids correlates with the presence of parMRC-like partitioning systems of different phylogenetic subfamilies.
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Affiliation(s)
- Thomas D Watts
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Priscilla A Johanesen
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Dena Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Julian I Rood
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Vicki Adams
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Victoria 3800, Australia.
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16
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Yamamoto S, Agustina V, Sakai A, Moriguchi K, Suzuki K. An extra repABC locus in the incRh2 Ti plasmid pTiBo542 exerts incompatibility toward an incRh1 plasmid. Plasmid 2017; 90:20-29. [PMID: 28238706 DOI: 10.1016/j.plasmid.2017.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/26/2017] [Accepted: 02/13/2017] [Indexed: 10/20/2022]
Abstract
Ti/Ri plasmids in pathogenic Agrobacterium species are repABC replicons that are stably maintained by the function of repABC genes. Two Ti plasmids, pTiBo542 and pTiS4, belonging to incRh2 and incRh4 incompatibility groups, respectively, were reported to carry two repABC loci. In the present study, to reveal the roles of the two repABC loci in the two plasmids, we constructed mini-replicons carrying any one or both of the repABC loci (referred to as repABC1 and repABC2 here) and examined their replication and incompatibility properties. The introduction of mini-replicons into A. tumefaciens C58C1 strains suggested that repABC1 functions as replicator genes but repABC2 does not in both the Ti plasmids. Because the components of repABC2 of pTiBo542 have highly similar amino acid and nucleotide sequences to those of the incRh1-type repABC replicon, we introduced repABC2-containing replicons into cells harboring an incRh1 plasmid in order to check their incompatibility traits. As a result, the repABC2-containing replicon expelled the resident incRh1 plasmid, indicating that the extra repABC locus is dispensable for replication and could work as an incompatibility determinant against incRh1 group plasmids. We suggest that the locus contributes to plasmid retention by eliminating the burden of co-existing competitive plasmids in host cells through its incompatibility.
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Affiliation(s)
- Shinji Yamamoto
- Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
| | - Vita Agustina
- Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Ayako Sakai
- Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Kazuki Moriguchi
- Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Katsunori Suzuki
- Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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Messerschmidt SJ, Schindler D, Zumkeller CM, Kemter FS, Schallopp N, Waldminghaus T. Optimization and Characterization of the Synthetic Secondary Chromosome synVicII in Escherichia coli. Front Bioeng Biotechnol 2016; 4:96. [PMID: 28066763 PMCID: PMC5179572 DOI: 10.3389/fbioe.2016.00096] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 12/09/2016] [Indexed: 11/15/2022] Open
Abstract
Learning by building is one of the core ideas of synthetic biology research. Consequently, building synthetic chromosomes is the way to fully understand chromosome characteristics. The last years have seen exciting synthetic chromosome studies. We had previously introduced the synthetic secondary chromosome synVicII in Escherichia coli. It is based on the replication mechanism of the secondary chromosome in Vibrio cholerae. Here, we present a detailed analysis of its genetic characteristics and a selection approach to optimize replicon stability. We probe the origin diversity of secondary chromosomes from Vibrionaceae by construction of several new respective replicons. Finally, we present a synVicII version 2.0 with several innovations including its full compatibility with the popular modular cloning (MoClo) assembly system.
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Affiliation(s)
- Sonja J Messerschmidt
- LOEWE Center for Synthetic Microbiology, SYNMIKRO, Philipps-Universität Marburg , Marburg , Germany
| | - Daniel Schindler
- LOEWE Center for Synthetic Microbiology, SYNMIKRO, Philipps-Universität Marburg , Marburg , Germany
| | - Celine M Zumkeller
- LOEWE Center for Synthetic Microbiology, SYNMIKRO, Philipps-Universität Marburg , Marburg , Germany
| | - Franziska S Kemter
- LOEWE Center for Synthetic Microbiology, SYNMIKRO, Philipps-Universität Marburg , Marburg , Germany
| | - Nadine Schallopp
- LOEWE Center for Synthetic Microbiology, SYNMIKRO, Philipps-Universität Marburg , Marburg , Germany
| | - Torsten Waldminghaus
- LOEWE Center for Synthetic Microbiology, SYNMIKRO, Philipps-Universität Marburg , Marburg , Germany
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18
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Abstract
The omnipresence of Arthrobacter species in polluted and toxic soils indicates their great potential in environmental biotechnologies, but practical applications of these bacteria are scarce mainly due to the availability of useful genetic engineering tools. Although many fully sequenced Arthrobacter genomes have been deposited in GenBank, little is known about the biology of their plasmids, especially the core functions: replication and partition. In this study the available Arthrobacter plasmid sequences were analyzed in order to identify their putative replication origin. At least the oris from the cryptic plasmids pXZ10142, pCG1, and pBL1 appear to work in this genus. Based on ParA homolog sequences, the Arthrobacter specific plasmids were classified into 4 clades. Iteron-like sequences were identified on most of the plasmids, indicating the position of the putative Arthrobacter specific oris. Although attempts were made to identify the core gene set required for plasmid replication in this genus, it was not possible. The plasmid proteomes showed a rather low similarity.
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20
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Diaz R, Rech J, Bouet JY. Imaging centromere-based incompatibilities: Insights into the mechanism of incompatibility mediated by low-copy number plasmids. Plasmid 2015; 80:54-62. [DOI: 10.1016/j.plasmid.2015.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 03/24/2015] [Accepted: 03/30/2015] [Indexed: 11/15/2022]
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Abstract
ABSTRACT
Whole-genome sequencing is revolutionizing the analysis of bacterial genomes. It leads to a massive increase in the amount of available data to be analyzed. Bacterial genomes are usually composed of one main chromosome and a number of accessory chromosomes, called plasmids. A recently developed methodology called PLACNET (for
pla
smid
c
onstellation
net
works) allows the reconstruction of the plasmids of a given genome. Thus, it opens an avenue for plasmidome analysis on a global scale. This work reviews our knowledge of the genetic determinants for plasmid propagation (conjugation and related functions), their diversity, and their prevalence in the variety of plasmids found by whole-genome sequencing. It focuses on the results obtained from a collection of 255
Escherichia coli
plasmids reconstructed by PLACNET. The plasmids found in
E. coli
represent a nonaleatory subset of the plasmids found in proteobacteria. Potential reasons for the prevalence of some specific plasmid groups will be discussed and, more importantly, additional questions will be posed.
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Characterization of a P1-like bacteriophage carrying an SHV-2 extended-spectrum β-lactamase from an Escherichia coli strain. Antimicrob Agents Chemother 2014; 58:6550-7. [PMID: 25136025 DOI: 10.1128/aac.03183-14] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
P1 bacteriophages lysogenize bacteria as independent plasmid-like elements. We describe here a P1-like bacteriophage, RCS47, carrying a blaSHV-2 gene, isolated from a clinical strain of Escherichia coli from phylogroup B1, and we report the prevalence of P1-like prophages in natural E. coli isolates. We found that 70% of the sequence of RCS47, a 115-kb circular molecule, was common to the reference P1 bacteriophage under GenBank accession no. AF234172.1, with the shared sequences being 99% identical. RCS47 had acquired two main foreign DNA fragments: a 9,636-bp fragment mobilized by two IS26 elements containing a blaSHV-2 gene, and an 8,544-bp fragment mobilized by two IS5 elements containing an operon encoding a dimethyl sulfoxide reductase. The reference P1 prophage plasmid replication gene belonged to the IncY incompatibility group, whereas that of RCS47 was from an unknown group. The lytic capacity of RCS47 and blaSHV-2 gene transduction, through the lysogenization of RCS47 in the recipient E. coli strains, were not demonstrated. The prevalence of P1-like prophages in various animal and human E. coli strain collections, as determined by the PCR detection of repL, the lytic replication gene, was 12.6%. No differences in the prevalences of these prophages were found between extended-spectrum β-lactamase (ESBL)-producing and non-ESBL-producing strains (P = 0.69), but this prevalence was lower in phylogroup B2 than in the other phylogroups (P = 0.008), suggesting epistatic interactions between P1 family phages and the genetic background of E. coli strains. P1-like phages are part of the mobile elements that carry antibiotic resistance. The high prevalence of P1-like prophages suggests their role may be underestimated.
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23
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Million-Weaver S, Camps M. Mechanisms of plasmid segregation: have multicopy plasmids been overlooked? Plasmid 2014; 75:27-36. [PMID: 25107339 DOI: 10.1016/j.plasmid.2014.07.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 07/20/2014] [Accepted: 07/21/2014] [Indexed: 11/29/2022]
Abstract
Plasmids are self-replicating pieces of DNA typically bearing non-essential genes. Given that plasmids represent a metabolic burden to the host, mechanisms ensuring plasmid transmission to daughter cells are critical for their stable maintenance in the population. Here we review these mechanisms, focusing on two active partition strategies common to low-copy plasmids: par systems type I and type II. Both involve three components: an adaptor protein, a motor protein, and a centromere, which is a sequence area in the plasmid that is recognized by the adaptor protein. The centromere-bound adaptor nucleates polymerization of the motor, leading to filament formation, which can pull plasmids apart (par I) or push them towards opposite poles of the cell (par II). No such active partition mechanisms are known to occur in high copy number plasmids. In this case, vertical transmission is generally considered stochastic, due to the random distribution of plasmids in the cytoplasm. We discuss conceptual and experimental lines of evidence questioning the random distribution model and posit the existence of a mechanism for segregation in high copy number plasmids that moves plasmids to cell poles to facilitate transmission to daughter cells. This mechanism would involve chromosomally-encoded proteins and the plasmid origin of replication. Modulation of this proposed mechanism of segregation could provide new ways to enhance plasmid stability in the context of recombinant gene expression, which is limiting for large-scale protein production and for bioremediation.
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Affiliation(s)
- Samuel Million-Weaver
- Department of Microbiology, University of Washington, Box 357735, Seattle, WA 98195-77352, United States
| | - Manel Camps
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, CA 95064, United States
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24
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A model for the evolution of biological specificity: a cross-reacting DNA-binding protein causes plasmid incompatibility. J Bacteriol 2014; 196:3002-11. [PMID: 24914185 DOI: 10.1128/jb.01811-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Few biological systems permit rigorous testing of how changes in DNA sequence give rise to adaptive phenotypes. In this study, we sought a simplified experimental system with a detailed understanding of the genotype-to-phenotype relationship that could be altered by environmental perturbations. We focused on plasmid fitness, i.e., the ability of plasmids to be stably maintained in a bacterial population, which is dictated by the plasmid's replication and segregation machinery. Although plasmid replication depends on host proteins, the type II plasmid partitioning (Par) machinery is entirely plasmid encoded and relies solely on three components: parC, a centromere-like DNA sequence, ParR, a DNA-binding protein that interacts with parC, and ParM, which forms actin-like filaments that push two plasmids away from each other at cell division. Interactions between the Par operons of two related plasmids can cause incompatibility and the reduced transmission of one or both plasmids. We have identified segregation-dependent plasmid incompatibility between the highly divergent Par operons of plasmids pB171 and pCP301. Genetic and biochemical studies revealed that the incompatibility is due to the functional promiscuity of the DNA-binding protein ParRpB171, which interacts with both parC DNA sequences to direct plasmid segregation, indicating that the lack of DNA binding specificity is detrimental to plasmid fitness in this environment. This study therefore successfully utilized plasmid segregation to dissect the molecular interactions between genotype, phenotype, and fitness.
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25
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Abstract
Evolutionary selection for optimal genome preservation, replication, and expression should yield similar chromosome organizations in any type of cells. And yet, the chromosome organization is surprisingly different between eukaryotes and prokaryotes. The nuclear versus cytoplasmic accommodation of genetic material accounts for the distinct eukaryotic and prokaryotic modes of genome evolution, but it falls short of explaining the differences in the chromosome organization. I propose that the two distinct ways to organize chromosomes are driven by the differences between the global-consecutive chromosome cycle of eukaryotes and the local-concurrent chromosome cycle of prokaryotes. Specifically, progressive chromosome segregation in prokaryotes demands a single duplicon per chromosome, while other "precarious" features of the prokaryotic chromosomes can be viewed as compensations for this severe restriction.
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26
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Wajima T, Sabui S, Kano S, Ramamurthy T, Chatterjee NS, Hamabata T. Entire sequence of the colonization factor coli surface antigen 6-encoding plasmid pCss165 from an enterotoxigenic Escherichia coli clinical isolate. Plasmid 2013; 70:343-52. [DOI: 10.1016/j.plasmid.2013.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 07/15/2013] [Accepted: 07/28/2013] [Indexed: 11/15/2022]
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RepA and RepB exert plasmid incompatibility repressing the transcription of the repABC operon. Plasmid 2013; 70:362-76. [PMID: 24016735 DOI: 10.1016/j.plasmid.2013.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/06/2013] [Accepted: 08/16/2013] [Indexed: 11/22/2022]
Abstract
Rhizobium etli CFN42 has a multipartite genome composed of one chromosome and six large plasmids with low copy numbers, all belonging to the repABC plasmid family. All elements essential for replication and segregation of these plasmids are encoded within the repABC operon. RepA and RepB direct plasmid segregation and are involved in the transcriptional regulation of the operon, and RepC is the initiator protein of the plasmid. Here we show that in addition to RepA (repressor) and RepB (corepressor), full transcriptional repression of the operon located in the symbiotic plasmid (pRetCFN42d) of this strain requires parS, the centromere-like sequence, and the operator sequence. However, the co-expression of RepA and RepB is sufficient to induce the displacement of the parental plasmid. RepA is a Walker-type ATPase that self associates in vivo and in vitro and binds specifically to the operator region in its RepA-ADP form. In contrast, RepA-ATP is capable of binding to non-specific DNA. RepA and RepB form high molecular weight DNA-protein complexes in the presence of ATP and ADP. RepA carrying ATP-pocket motif mutations induce full repression of the repABC operon without the participation of RepB and parS. These mutants specifically bind the operator sequence in their ATP or ADP bound forms. In addition, their expression in trans exerts plasmid incompatibility against the parental plasmid. RepA and RepB expressed in trans induce plasmid incompatibility because of their ability to repress the repABC operon and not only by their capacity to distort the plasmid segregation process.
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28
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Lin MH, Fu JF, Liu ST. A repeat sequence causes competition of ColE1-type plasmids. PLoS One 2013; 8:e61668. [PMID: 23613898 PMCID: PMC3628316 DOI: 10.1371/journal.pone.0061668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 03/11/2013] [Indexed: 11/18/2022] Open
Abstract
Plasmid pSW200 from Pantoea stewartii contains 41 copies of 15-bp repeats and has a replicon that is homologous to that of ColE1. Although deleting the repeats (pSW207) does not change the copy number and stability of the plasmid. The plasmid becomes unstable and is rapidly lost from the host when a homoplasmid with the repeats (pSW201) is present. Deleting the repeats is found to reduce the transcriptional activity of RNAIp and RNAIIp by about 30%, indicating that the repeats promote the transcription of RNAI and RNAII, and how the RNAI that is synthesized by pSW201 inhibits the replication of pSW207. The immunoblot analysis herein demonstrates that RNA polymerase β subunit and σ(70) in the lysate from Escherichia coli MG1655 bind to a biotin-labeled DNA probe that contains the entire sequence of the repeat region. Electrophoretic mobility shift assay also reveals that purified RNA polymerase shifts a DNA probe that contains four copies of the repeats. These results thus obtained reveal that RNA polymerase holoenzyme binds to the repeats. The repeats also exchange RNA polymerase with RNAIp and RNAIIp in vitro, revealing the mechanism by which the transcription is promoted. This investigation elucidates a mechanism by which a plasmid prevents the invasion of an incompatible plasmid and maintains its stability in the host cell during evolution.
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Affiliation(s)
- Mei-Hui Lin
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Research Center for Pathogenic Bacteria, Chang Gung University, Taoyuan, Taiwan
| | - Jen-Fen Fu
- Department of Medical Research, Chang Gung Memorial Hospital, and Graduate Institute of Clinical Medical Sciences Taoyuan, Taiwan
| | - Shih-Tung Liu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Research Center for Pathogenic Bacteria, Chang Gung University, Taoyuan, Taiwan
- * E-mail:
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29
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Bleicher A, Schöfl G, Rodicio MDR, Saluz HP. The plasmidome of a Salmonella enterica serovar Derby isolated from pork meat. Plasmid 2013; 69:202-10. [PMID: 23333216 DOI: 10.1016/j.plasmid.2013.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/04/2013] [Accepted: 01/06/2013] [Indexed: 10/27/2022]
Abstract
The complete nucleotide sequences of four plasmids hosted by a Salmonella enterica serovar. Derby strain 6MK1 isolated from pork were determined by shotgun Sanger sequencing. A 107,637 base pairs (bp) conjugative plasmid pSD107 containing 150 putative coding sequences (CDS) could be assigned to the narrow host range incompatibility group IncI1. A detailed annotation of all CDS was carried out, revealing the presence of genes needed for plasmid replication, conjugal transfer, plasmid partitioning and stability as well as resistance to antimicrobials. The resistance determinants dhfrA1, aadA1, qacEΔ1, sul1 (supplied by a class 1 integron), blaTEM-1b (carried by a truncated Tn2 flanked by IS26), sul2 and strAB confer multidrug resistance to the host bacterium. In addition to pSD107, three small cryptic plasmids pSD4.0, pSD4.6 and pSD5.6 were identified, showing significant sequence similarities to already known replicons of Escherichia coli and S. enterica. In conjugation experiments performed on solid medium, pSD107 was successfully transferred to a nalidixic acid resistant E. coli DH5α, mobilizing pSD4.0 and, more infrequently, also pSD4.6. All transferred plasmids were stably propagated in the recipient strain without selective pressure for approximately 66 generations. The absolute plasmid copy numbers were determined in real time PCR experiments, revealing an approximate 1:1:1:1 ratio of the four replicons compared to the chromosome. The evolutionary position of pSD107 within the IncI1 family of plasmids was inferred from a maximum likelihood phylogenetic tree and by comparison of genetic key elements in a set of 17 IncI1 reference plasmids.
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Affiliation(s)
- Anne Bleicher
- Leibniz-Institute for Natural Product Research and Infection Biology, Beutenbergstrasse 11a, Cell and Molecular Biology, D-07745 Jena, Germany.
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Demarre G, Galli E, Barre FX. The FtsK Family of DNA Pumps. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 767:245-62. [PMID: 23161015 DOI: 10.1007/978-1-4614-5037-5_12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Interest for proteins of the FtsK family initially arose from their implication in many primordial processes in which DNA needs to be transported from one cell compartment to another in eubacteria. In the first section of this chapter, we address a list of the cellular functions of the different members of the FtsK family that have been so far studied. Soon after their discovery, interest for the FstK proteins spread because of their unique biochemical properties: most DNA transport systems rely on the assembly of complex multicomponent machines. In contrast, six FtsK proteins are sufficient to assemble into a fast and powerful DNA pump; the pump transports closed circular double stranded DNA molecules without any covalent-bond breakage nor topological alteration; transport is oriented despite the intrinsic symmetrical nature of the double stranded DNA helix and can occur across cell membranes. The different activities required for the oriented transport of DNA across cell compartments are achieved by three separate modules within the FtsK proteins: a DNA translocation module, an orientation module and an anchoring module. In the second part of this chapter, we review the structural and biochemical properties of these different modules.
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Affiliation(s)
- Gaëlle Demarre
- Centre de Génétique Moléculaire, CNRS, Gif sur Yvette, Cedex, France,
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31
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Sequence of two plasmids from Clostridium perfringens chicken necrotic enteritis isolates and comparison with C. perfringens conjugative plasmids. PLoS One 2012. [PMID: 23189158 PMCID: PMC3506638 DOI: 10.1371/journal.pone.0049753] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Twenty-six isolates of Clostridium perfringens of different MLST types from chickens with necrotic enteritis (NE) (15 netB-positive) or from healthy chickens (6 netB-positive, 5 netB-negative) were found to contain 1–4 large plasmids, with most netB-positive isolates containing 3 large and variably sized plasmids which were more numerous and larger than plasmids in netB-negative isolates. NetB and cpb2 were found on different plasmids consistent with previous studies. The pathogenicity locus NELoc1, which includes netB, was largely conserved in these plasmids whereas NeLoc3, present in the cpb2 containing plasmids, was less well conserved. A netB-positive and a cpb2-positive plasmid were likely to be conjugative, and the plasmids were completely sequenced. Both plasmids possessed the intact tcp conjugative region characteristic of C. perfringens conjugative plasmids. Comparative genomic analysis of nine CpCPs, including the two plasmids described here, showed extensive gene rearrangements including pathogenicity locus and accessory gene insertions around rather than within the backbone region. The pattern that emerges from this analysis is that the major toxin-containing regions of the variety of virulence-associated CpCPs are organized as complex pathogenicity loci. How these different but related CpCPs can co-exist in the same host has been an unanswered question. Analysis of the replication-partition region of these plasmids suggests that this region controls plasmid incompatibility, and that CpCPs can be grouped into at least four incompatibility groups.
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Miyakoshi M, Shintani M, Inoue K, Terabayashi T, Sai F, Ohkuma M, Nojiri H, Nagata Y, Tsuda M. ParI, an orphan ParA family protein from Pseudomonas putida KT2440-specific genomic island, interferes with the partition system of IncP-7 plasmids. Environ Microbiol 2012; 14:2946-59. [PMID: 22925377 DOI: 10.1111/j.1462-2920.2012.02861.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 07/26/2012] [Accepted: 07/28/2012] [Indexed: 01/09/2023]
Abstract
Pseudomonas putida KT2440 is an ideal soil bacterium for expanding the range of degradable compounds via the recruitment of various catabolic plasmids. In the course of our investigation of the host range of IncP-7 catabolic plasmids pCAR1, pDK1 and pWW53, we found that the IncP-7 miniplasmids composed of replication and partition loci were exceptionally unstable in KT2440, which is the authentic host of the archetypal IncP-9 plasmid pWW0. This study identified ParI, a homologue of ParA family of plasmid partitioning proteins encoded on the KT2440-specific cryptic genomic island, as a negative host factor for the maintenance of IncP-7 plasmids. The miniplasmids were destabilized by ectopic expression of ParI, and the loss rate correlated with the copy number of ParB binding sites in the centromeric parS region. Mutations in the conserved ATPase domains of ParI abolished destabilization of miniplasmids. Furthermore, ParI destabilized miniplasmid derivatives carrying the partition-deficient parA mutations but failed to impact the stability of miniplasmid derivatives with parB mutations in the putative arginine finger. Altogether, these results indicate that ParI interferes with the IncP-7 plasmid partition system. This study extends canonical partition-mediated incompatibility of plasmids beyond heterogeneous mobile genetic elements, namely incompatibility between plasmid and genomic island.
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Affiliation(s)
- Masatoshi Miyakoshi
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan.
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Siddique A, Figurski DH. Different phenotypes of Walker-like A box mutants of ParA homolog IncC of broad-host-range IncP plasmids. Plasmid 2012; 68:93-104. [PMID: 22579980 DOI: 10.1016/j.plasmid.2012.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 03/27/2012] [Accepted: 04/02/2012] [Indexed: 11/30/2022]
Abstract
The promiscuous IncPα plasmids RK2 and R995 encode a broad-host-range partition system, whose essential components include the incC and korB genes and a DNA site (O(B)) to which the korB product binds. IncC2, the smaller of the two incC products, is sufficient for stabilization of R995ΔincC. It is a member of the type Ia ParA family of partition ATPases. To better understand the role of ATP in partition, we constructed three alanine-substitution mutants of IncC2. Each mutation changed a different residue of the Walker-like ATP-binding and hydrolysis motif, including a lysine (K10) conserved solely among members of the ParA and MinD families. All three IncC2 mutants were defective in plasmid partition, but they differed from one another in other respects. The IncC2 T16A mutant, predicted to be defective in Mg²⁺ coordination, was severely impaired in all activities tested. IncC2 K10A, predicted to be defective in ATP hydrolysis, mediated enhanced incompatibility with R995 derivatives. IncC2 K15A, predicted to be defective in ATP binding, exhibited two distinct incompatibility properties depending on the genotype of the target plasmid. When in trans to plasmids carrying a complementable incC deletion, IncC2 K15A caused dramatic plasmid loss, even at low levels of expression. In trans to wild-type R995 or to R995ΔincC carrying a functional P1 partition system, IncC2 K15A-mediated incompatibility was significantly less than that caused by wild-type IncC2. All three Walker-like A box mutants were also defective for the host toxicity that normally results from co-overexpression of incC and korB. The phenotypes of the mutants support a model in which nucleotide hydrolysis is required for separation of paired plasmid complexes and possible interaction with a host factor.
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Affiliation(s)
- Azeem Siddique
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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ParAB-mediated intermolecular association of plasmid P1 parS sites. Virology 2011; 421:192-201. [PMID: 22018490 DOI: 10.1016/j.virol.2011.09.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/05/2011] [Accepted: 09/28/2011] [Indexed: 11/20/2022]
Abstract
The P1 plasmid partition system depends on ParA-ParB proteins acting on centromere-like parS sites for a faithful plasmid segregation during the Escherichia coli cell cycle. In vivo we placed parS into host E. coli chromosome and on a Sop(+) F plasmid and found that the stability of a P1 plasmid deleted for parA-parB could be partially restored when parB was expressed in trans. In vitro, parS, conjugated to magnetic beads could capture free parS DNA fragment in presence of ParB. In vitro, ParA stimulated ParB-mediated association of intermolecular parS sites in an ATP-dependent manner. However, in the presence of ADP, ParA reduced ParB-mediated pairing to levels below that seen by ParB alone. ParB of P1 pairs the parS sites of plasmids in vivo and fragments in vitro. Our findings support a model whereby ParB complexes P1 plasmids, ParA-ATP stimulates this interaction and ParA-ADP inhibits ParB pairing activity in a parS-independent manner.
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Guynet C, de la Cruz F. Plasmid segregation without partition. Mob Genet Elements 2011; 1:236-241. [PMID: 22312593 DOI: 10.4161/mge.1.3.18229] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 09/27/2011] [Indexed: 11/19/2022] Open
Abstract
Low-copy number plasmids need a segregation mechanism to assort one half of the plasmid copies to each daughter cell during cell division. This can be achieved directly by partitioning plasmid copies through a mechanism reminiscent of eukaryotic mitosis. Briefly, plasmid copies are paired around a centromere-like site, and then separated toward the daughter cells at cell division. Partition mechanisms are used by a majority of well-studied plasmids. They involve two proteins, a DNA-binding protein and a motor protein, besides the centromeric site. However, some plasmids do not encode typical partition systems, so alternative segregation mechanisms must be considered. For instance, chromosome segregation could provide the driving force for plasmid movement, through a "pilot-fish"-like mechanism. In support of this assumption, we recently demonstrated that plasmid R388 segregation, which does not involve a plasmid-encoded motor protein, requires a single plasmid-encoded DNA-binding protein. Besides, the new segregation system becomes essential when the plasmid encodes conjugation machinery, providing a new understanding of how plasmids integrate conjugative transfer with segregation.
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Affiliation(s)
- Catherine Guynet
- IBBTEC; Instituto de Biomedicina y Biotecnologia de Cantabria (CSIC-UC-SODERCAN); Facultad de Medicina; Universidad de Cantabria; Santander, Spain
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Acquisition of antimicrobial resistance determinants by virulence plasmids specific for nontyphoid serovars of Salmonella enterica. ACTA ACUST UNITED AC 2011. [DOI: 10.1097/mrm.0b013e328346d87d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Baquero F. The 2010 Garrod Lecture: The dimensions of evolution in antibiotic resistance: ex unibus plurum et ex pluribus unum. J Antimicrob Chemother 2011; 66:1659-72. [DOI: 10.1093/jac/dkr214] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Pillet F, Sanchez A, Lane D, Anton Leberre V, Bouet JY. Centromere binding specificity in assembly of the F plasmid partition complex. Nucleic Acids Res 2011; 39:7477-86. [PMID: 21653553 PMCID: PMC3177203 DOI: 10.1093/nar/gkr457] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The segregation of plasmid F of Escherichia coli is highly reliable. The Sop partition locus, responsible for this stable maintenance, is composed of two genes, sopA and sopB and a centromere, sopC, consisting of 12 direct repeats of 43 bp. Each repeat carries a 16-bp inverted repeat motif to which SopB binds to form a nucleoprotein assembly called the partition complex. A database search for sequences closely related to sopC revealed unexpected features that appeared highly conserved. We have investigated the requirements for specific SopB-sopC interactions using a surface plasmon resonance imaging technique. We show that (i) only 10 repeats interact specifically with SopB, (ii) no base outside the 16-bp sopC sites is involved in binding specificity, whereas five bases present in each arm are required for interactions, and (iii) the A-C central bases contribute to binding efficiency by conforming to a need for a purine-pyrimidine dinucleotide. We have refined the SopB-sopC binding pattern by electro-mobility shift assay and found that all 16 bp are necessary for optimal SopB binding. These data and the model we propose, define the basis of the high binding specificity of F partition complex assembly, without which, dispersal of SopB over DNA would result in defective segregation.
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Affiliation(s)
- Flavien Pillet
- Université de Toulouse, INSA, UPS, INP, LISBP, Toulouse, France
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Guynet C, Cuevas A, Moncalián G, de la Cruz F. The stb operon balances the requirements for vegetative stability and conjugative transfer of plasmid R388. PLoS Genet 2011; 7:e1002073. [PMID: 21625564 PMCID: PMC3098194 DOI: 10.1371/journal.pgen.1002073] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 03/24/2011] [Indexed: 11/24/2022] Open
Abstract
The conjugative plasmid R388 and a number of other plasmids carry an operon, stbABC, adjacent to the origin of conjugative transfer. We investigated the role of the stbA, stbB, and stbC genes. Deletion of stbA affected both conjugation and stability. It led to a 50-fold increase in R388 transfer frequency, as well as to high plasmid loss. In contrast, deletion of stbB abolished conjugation but provoked no change in plasmid stability. Deletion of stbC showed no effect, neither in conjugation nor in stability. Deletion of the entire stb operon had no effect on conjugation, which remained as in the wild-type plasmid, but led to a plasmid loss phenotype similar to that of the R388ΔstbA mutant. We concluded that StbA is required for plasmid stability and that StbA and StbB control conjugation. We next observed the intracellular positioning of R388 DNA molecules and showed that they localize as discrete foci evenly distributed in live Escherichia coli cells. Plasmid instability of the R388ΔΔstbA mutant correlated with aberrant localization of the plasmid DNA molecules as clusters, either at one cell pole, at both poles, or at the cell center. In contrast, plasmid molecules in the R388ΔΔstbB mutant were mostly excluded from the cell poles. Thus, results indicate that defects in both plasmid maintenance and transfer are a consequence of variations in the intracellular positioning of plasmid DNA. We propose that StbA and StbB constitute an atypical plasmid stabilization system that reconciles two modes of plasmid R388 physiology: a maintenance mode (replication and segregation) and a propagation mode (conjugation). The consequences of this novel concept in plasmid physiology will be discussed. The ability of bacteria to evolve and adapt to new environments most often results from the acquisition of new genes by horizontal transfer. Plasmids have a preponderant role in gene exchanges through their ability to transfer DNA by conjugation, a process that transports DNA between bacteria. Besides, plasmids are autonomous DNA molecules that are faithfully transmitted to cell progeny during vegetative cell multiplication. In this study, we report a system composed of two proteins, StbA and StbB, which act to balance plasmid R388 physiology between two modes: a maintenance mode (vertical transmission) and a propagation mode (horizontal transmission). We demonstrate that StbA is essential to ensure faithful assortment of plasmid copies to daughter cells. In turn, StbB is required for plasmid R388 adequate localization for conjugation. This is the first report of a system which reconciles plasmid segregation and conjugation. Furthermore, R388 belongs to the IncW family of conjugative plasmids, which are of particular interest due to their exceptionally broad host range. We show that the StbAB system is conserved among a wide variety of conjugative plasmids, mainly broad host range plasmids. Thus, the Stb system could constitute an interesting therapeutic target to prevent the spread of adaptive genes.
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Affiliation(s)
- Catherine Guynet
- IBBTEC, Instituto de Biomedicina y Biotecnologia de Cantabria (CSIC-UC-SODERCAN), Facultad de Medicina, Universidad de Cantabria, Santander, Spain
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Dam B. A type Ib plasmid segregation machinery of the Advenella kashmirensis plasmid pBTK445. Plasmid 2010; 65:185-91. [PMID: 21192970 DOI: 10.1016/j.plasmid.2010.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 12/17/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
Abstract
pBTK445 is a newly described large (∼60Kb), low-copy number, conjugative plasmid indigenous to the sulfur-chemolithoautotroph Advenella kashmirensis. Based on its minimal replication region, a shuttle vector, pBTKS was constructed which can be used for diverse Alcaligenaceae members. The construct was found to be stably maintained both in the native host as well as in Escherichia coli in the absence of selective pressure which indicated that pBTKS harbors the stabilizing system of pBTK445, that are commonly coded by low-copy-number plasmids. Deletion analyzes of pBTKS confirmed the essentiality of parA (encoding a Walker-type ATPase of 214 amino acids) and the downstream located small parB (encoding an 85 amino acid protein having no sequence homolog in the database) in the faithful partitioning of pBTK445. A 1075bp PCR product, containing parA, parB and an upstream sequence having nine 11bp direct repeats (parS site) was found to comprise the partition functions of pBTK445, stabilizing both low-copy or high-copy number homologous and heterologous replicons in diverse hosts. The incompatibility determinant and the par promoter, P(par) were both found to be present within a 191bp iterated sequence present upstream of parA. ParB was found to regulate the expression of the Par proteins from P(par). The presence of a typical Walker-type ATPase motif in ParA, a short phylogenetically unrelated ParB, that acts as a repressor of P(par), and location of the iterated parS site upstream of parA, confirm that the active partition system of pBTK445 belongs to the type Ib.
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Affiliation(s)
- Bomba Dam
- Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Karl Von Frisch Strasse 10, D-35043 Marburg, Germany.
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Petersen J, Brinkmann H, Berger M, Brinkhoff T, Päuker O, Pradella S. Origin and evolution of a novel DnaA-like plasmid replication type in Rhodobacterales. Mol Biol Evol 2010; 28:1229-40. [PMID: 21097494 DOI: 10.1093/molbev/msq310] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Large extrachromosomal elements are widespread among Alphaproteobacteria, but it is unclear how up to a dozen low-copy plasmids can stably coexist within the same cell. We systematically analyzed the distribution of different replicons in about 40 completely sequenced genomes of the Roseobacter clade (Rhodobacterales) and surprisingly identified a novel plasmid replicon type. The conserved replication module comprises the characteristic partitioning operon (parAB) and a hitherto unknown replicase. The latter shows a weak homology to the chromosomal replication initiator DnaA and was accordingly named "DnaA-like." Phylogenetic analyses of the adjacent parAB genes document a common ancestry with repA- and repB-type plasmids and moreover indicate the presence of two dnaA-like compatibility groups. This conclusion is supported by conserved palindrome sequences within the replication module that probably represent crucial centromeric anchors for plasmid partitioning. The functionality of dnaA-like replicons was proven by transformation experiments in Phaeobacter gallaeciensis BS107 (DSM 17395). This Roseobacter strain furthermore allows the phenotypical monitoring of plasmid incompatibility, based on a 262-kb dnaA-like replicon required for the brown pigmentation of the bacterium. Uptake of an incompatible construct induces its loss, hence resulting in white colonies. Accordingly, we could substantiate the in silico predictions about stable maintenance of dnaA-like plasmids and thereby functionally validate our approach of plasmid classification based on phylogenetic analyses.
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Affiliation(s)
- Jörn Petersen
- DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Department of Molecular Systematics, Braunschweig, Germany.
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Characterization of toxin plasmids in Clostridium perfringens type C isolates. Infect Immun 2010; 78:4860-9. [PMID: 20823204 DOI: 10.1128/iai.00715-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Clostridium perfringens type C isolates cause enteritis necroticans in humans or necrotizing enteritis and enterotoxemia in domestic animals. Type C isolates always produce alpha toxin and beta toxin but often produce additional toxins, e.g., beta2 toxin or enterotoxin. Since plasmid carriage of toxin-encoding genes has not been systematically investigated for type C isolates, the current study used Southern blot hybridization of pulsed-field gels to test whether several toxin genes are plasmid borne among a collection of type C isolates. Those analyses revealed that the surveyed type C isolates carry their beta toxin-encoding gene (cpb) on plasmids ranging in size from ∼65 to ∼110 kb. When present in these type C isolates, the beta2 toxin gene localized to plasmids distinct from the cpb plasmid. However, some enterotoxin-positive type C isolates appeared to carry their enterotoxin-encoding cpe gene on a cpb plasmid. The tpeL gene encoding the large clostridial cytotoxin was localized to the cpb plasmids of some cpe-negative type C isolates. The cpb plasmids in most surveyed isolates were found to carry both IS1151 sequences and the tcp genes, which can mediate conjugative C. perfringens plasmid transfer. A dcm gene, which is often present near C. perfringens plasmid-borne toxin genes, was identified upstream of the cpb gene in many type C isolates. Overlapping PCR analyses suggested that the toxin-encoding plasmids of the surveyed type C isolates differ from the cpe plasmids of type A isolates. These findings provide new insight into plasmids of proven or potential importance for type C virulence.
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Tsuchida Y, Kimura S, Suzuki N, Inui M, Yukawa H. Characterization of a 24-kb plasmid pCGR2 newly isolated from Corynebacterium glutamicum. Appl Microbiol Biotechnol 2010; 87:1855-66. [DOI: 10.1007/s00253-010-2701-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 05/24/2010] [Accepted: 05/25/2010] [Indexed: 11/25/2022]
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Wide dispersal and possible multiple origins of low-copy-number plasmids in rickettsia species associated with blood-feeding arthropods. Appl Environ Microbiol 2010; 76:1718-31. [PMID: 20097813 DOI: 10.1128/aem.02988-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Plasmids are mobile genetic elements of bacteria that can impart important adaptive traits, such as increased virulence or antibiotic resistance. We report the existence of plasmids in Rickettsia (Rickettsiales; Rickettsiaceae) species, including Rickettsia akari, "Candidatus Rickettsia amblyommii," R. bellii, R. rhipicephali, and REIS, the rickettsial endosymbiont of Ixodes scapularis. All of the rickettsiae were isolated from humans or North and South American ticks. R. parkeri isolates from both continents did not possess plasmids. We have now demonstrated plasmids in nearly all Rickettsia species that we have surveyed from three continents, which represent three of the four major proposed phylogenetic groups associated with blood-feeding arthropods. Gel-based evidence consistent with the existence of multiple plasmids in some species was confirmed by cloning plasmids with very different sequences from each of two "Ca. Rickettsia amblyommii" isolates. Phylogenetic analysis of rickettsial ParA plasmid partitioning proteins indicated multiple parA gene origins and plasmid incompatibility groups, consistent with possible multiple plasmid origins. Phylogenetic analysis of potentially host-adaptive rickettsial small heat shock proteins showed that hsp2 genes were plasmid specific and that hsp1 genes, found only on plasmids of "Ca. Rickettsia amblyommii," R. felis, R. monacensis, and R. peacockii, were probably acquired independently of the hsp2 genes. Plasmid copy numbers in seven Rickettsia species ranged from 2.4 to 9.2 per chromosomal equivalent, as determined by real-time quantitative PCR. Plasmids may be of significance in rickettsial evolution and epidemiology by conferring genetic plasticity and host-adaptive traits via horizontal gene transfer that counteracts the reductive genome evolution typical of obligate intracellular bacteria.
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Yi H, Xi Y, Liu J, Wang J, Wu J, Xu T, Chen W, Chen B, Lin M, Wang H, Zhou M, Li J, Xu Z, Jin S, Bao Q. Sequence analysis of pKF3-70 in Klebsiella pneumoniae: probable origin from R100-like plasmid of Escherichia coli. PLoS One 2010; 5:e8601. [PMID: 20066042 PMCID: PMC2797631 DOI: 10.1371/journal.pone.0008601] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Accepted: 12/01/2009] [Indexed: 11/25/2022] Open
Abstract
Background Klebsiella pneumoniae is a clinically significant species of bacterium which causes a variety of diseases. Clinical treatment of this bacterial infection is greatly hindered by the emergence of multidrug-resistant strains. The resistance is largely due to the acquisition of plasmids carrying drug-resistant as well as pathogenic genes, and its conjugal transfer facilitates the spread of resistant phenotypes. Methodology/Principal Findings The 70,057 bp plasmid pKF3-70, commonly found in Klebsiella pneumoniae, is composed of five main functional modules, including regions involved in replication, partition, conjugation, transfer leading, and variable regions. This plasmid is more similar to several Escherichia coli plasmids than any previously reported K. pneumoniae plasmids and pKF3-70 like plasmids share a common and conserved backbone sequence. The replication system of the pKF3-70 is 100% identical to that of RepFII plasmid R100 from E. coli. A beta-lactamase gene ctx-m-14 with its surrounding insertion elements (ISEcp1, truncated IS903 and a 20 bp inverted repeat sequence) may compose an active transposon which is directly bordered by two putative target repeats “ATTAC.” Conclusions/Significance The K. pneumoniae plasmid pKF3-70 carries an extended-spectrum beta-lactamase gene, ctx-m-14. The conjugative characteristic makes it a widespread plasmid among genetically relevant genera which poses significant threat to public health.
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Affiliation(s)
- Huiguang Yi
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
- T-Life Research Center, Fudan University, Shanghai, China
| | - Yali Xi
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Jing Liu
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Junrong Wang
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Jinyu Wu
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Teng Xu
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Wei Chen
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Biaobang Chen
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Meili Lin
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Huan Wang
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Mingming Zhou
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Jinsong Li
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Zuyuan Xu
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
| | - Shouguang Jin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
| | - Qiyu Bao
- Institute of Biomedical Informatics/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China
- * E-mail:
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Norman A, Hansen LH, Sørensen SJ. Conjugative plasmids: vessels of the communal gene pool. Philos Trans R Soc Lond B Biol Sci 2009; 364:2275-89. [PMID: 19571247 DOI: 10.1098/rstb.2009.0037] [Citation(s) in RCA: 312] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Comparative whole-genome analyses have demonstrated that horizontal gene transfer (HGT) provides a significant contribution to prokaryotic genome innovation. The evolution of specific prokaryotes is therefore tightly linked to the environment in which they live and the communal pool of genes available within that environment. Here we use the term supergenome to describe the set of all genes that a prokaryotic 'individual' can draw on within a particular environmental setting. Conjugative plasmids can be considered particularly successful entities within the communal pool, which have enabled HGT over large taxonomic distances. These plasmids are collections of discrete regions of genes that function as 'backbone modules' to undertake different aspects of overall plasmid maintenance and propagation. Conjugative plasmids often carry suites of 'accessory elements' that contribute adaptive traits to the hosts and, potentially, other resident prokaryotes within specific environmental niches. Insight into the evolution of plasmid modules therefore contributes to our knowledge of gene dissemination and evolution within prokaryotic communities. This communal pool provides the prokaryotes with an important mechanistic framework for obtaining adaptability and functional diversity that alleviates the need for large genomes of specialized 'private genes'.
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Affiliation(s)
- Anders Norman
- Department of Biology, Section for Evolution and Microbiology, University of Copenhagen, Copenhagen K, Denmark.
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Abstract
An 8,883-bp mini-pXO1 plasmid containing a replicon from Bacillus anthracis pXO1 (181.6 kb) was identified by making large deletions in the original plasmid using a newly developed Cre-loxP system. Portions of the truncated mini-pXO1 were cloned into an Escherichia coli vector unable to replicate in B. anthracis. A 5.95-kb region encompassing three putative genes was identified as the minimal pXO1 fragment required for replication of the resulting recombinant shuttle plasmid (named pMR) in B. anthracis. Deletion analysis showed that the only genes essential for replication were the pXO1-14 and pXO1-16 genes, which are transcribed in opposite directions and encode predicted proteins of 66.5 and 67.1 kDa, respectively. The ORF14 protein contains a helix-turn-helix motif, while the ORF16 upstream region contains attributes of a theta-replicating plasmid origin of replication (Ori), namely, an exclusively A+T-containing segment, five 9-bp direct repeats, an inverted repeat, and a sigma(A)-dependent promoter for the putative replication initiator Rep protein (ORF16). Spontaneous mutations generated in the ORF14, ORF16, and Ori regions of pMR during PCR amplification produced a temperature-sensitive plasmid that is unable to replicate in B. anthracis at 37 degrees C. The efficacy of transformation of plasmid-free B. anthracis Ames and Sterne strains by the original pMR was approximately 10(3) CFU/microg, while Bacillus cereus strains 569 and ATCC 10987 were transformed with efficiencies of 10(4) and 10(2) CFU/microg, respectively. Around 95% of B. anthracis cells retained pMR after one round of sporulation and germination.
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Breton M, Duret S, Arricau-Bouvery N, Béven L, Renaudin J. Characterizing the replication and stability regions of Spiroplasma citri plasmids identifies a novel replication protein and expands the genetic toolbox for plant-pathogenic spiroplasmas. MICROBIOLOGY-SGM 2008; 154:3232-3244. [PMID: 18832328 DOI: 10.1099/mic.0.2008/019562-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Spiroplasma citri strain GII3 contains seven plasmids, pSciA and pSci1-6, that share extensive regions of sequence homology and display a mosaic gene organization. Plasmid pSci2 comprises 12 coding sequences (CDS), three of which encode polypeptides homologous to proteins Soj/ParA, involved in chromosome partitioning, and TrsE and Mob/TraG, implicated in the type IV secretion pathway. One CDS encodes the adhesin-like protein ScARP3d whereas the other eight encode polypeptides with no homology to known proteins. The pSci2 CDS pE and soj have counterparts in all seven plasmids. Through successive deletions, various pSci2 derivatives were constructed and assessed for their ability to replicate by transformation of S. citri 44, a strain which has no plasmid. The smallest functional replicon was found to contain a single CDS (pE) and its flanking intergenic regions. Shuttle (S. citri/Escherichia coli) plasmids, in which CDS pE was disrupted, failed to replicate in S. citri, suggesting that PE is the replication protein of the S. citri plasmids. Successive propagations of pSci2-derived transformed spiroplasmas, in the absence of selection pressure, revealed that only pSci2 derivatives having an intact soj gene were stably maintained, indicating that the soj-encoded polypeptide is most likely involved in plasmid partitioning. Upon transformation, pSci2 derivatives, including shuttle (S. citri/E. coli) plasmids, were shown to replicate in all S. citri strains tested regardless of whether the strain possesses endogenous plasmids, such as strain GII3, or not, such as strain R8A2. In addition, the pSci replicons were introduced efficiently into the plant-pathogenic spiroplasmas Spiroplasma kunkelii and Spiroplasma phoeniceum, the transformation of which had never, to our knowledge, been described before. These studies show that, besides their implications for the biology of S. citri, the pSci plasmids hold considerable promise as vectors of general use for genetic studies of plant-pathogenic spiroplasmas. As an example, a HA-tagged S. citri protein was expressed in S. kunkelii. Detection of pE-hybridizing sequences in various group I spiroplasma species indicated that pE replicating plasmids were not restricted to the three plant-pathogenic spiroplasmas.
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Affiliation(s)
- Marc Breton
- Université de Bordeaux 2, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
| | - Sybille Duret
- Université de Bordeaux 2, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
| | - Nathalie Arricau-Bouvery
- Université de Bordeaux 2, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
| | - Laure Béven
- Université de Bordeaux 2, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
| | - Joël Renaudin
- Université de Bordeaux 2, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
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49
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Tsuchida Y, Kimura S, Suzuki N, Inui M, Yukawa H. Characterization of a new 2.4-kb plasmid of Corynebacterium casei and development of stable corynebacterial cloning vector. Appl Microbiol Biotechnol 2008; 81:1107-15. [PMID: 18936936 DOI: 10.1007/s00253-008-1746-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 10/02/2008] [Accepted: 10/02/2008] [Indexed: 10/21/2022]
Abstract
A new plasmid pCASE1 was isolated from Gram-positive Corynebacterium casei JCM 12072. It comprised a 2.4-kb nucleotide sequence with three ORFs, two of which were indispensable for autonomous replication in Corynebacterium glutamicum. Homology search identified these two ORFs as repA and repB, areas coding proteins involved in plasmid replication. repA sequence showed high similarity to theta-replicating Escherichia coli ColE2-P9 plasmids and even higher similarity to plasmids derived from Gram-positive bacteria belonging to a subfamily of this ColE2-P9 group. An E. coli-C. glutamicum shuttle vector was constructed with pCASE1 fragment including repA and repB to transform C. glutamicum and showed compatibility with corynebacterial plasmids from different plasmid families. The copy number of the shuttle vector in C. glutamicum was 13 and the vector showed stability for 102 generations with no selective pressure.
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Affiliation(s)
- Yoshiki Tsuchida
- Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
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50
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Abstract
Recent in vitro and in vivo studies of the proteins responsible for the active partitioning of bacterial plasmids suggest that it will be possible to develop a quantitative, molecular understanding of this form of DNA segregation.
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Affiliation(s)
- Daniel J Needleman
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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