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Sakai M, Shimosaka T, Katsumata K, Yohda M, Narumi I. Developing a new host-vector system for Deinococcus grandis. Front Microbiol 2024; 15:1387296. [PMID: 38863757 PMCID: PMC11165121 DOI: 10.3389/fmicb.2024.1387296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 04/26/2024] [Indexed: 06/13/2024] Open
Abstract
Deinococcus spp. are known for their radiation resistance, toxic compound removal, and production of valuable substances. Therefore, developing gene expression systems for Deinococcus spp. is crucial in advancing genetic engineering applications. To date, plasmid vectors that express foreign genes in D. radiodurans and D. geothermalis have been limited to plasmid pI3 and its derivatives. In contrast, plasmid vectors that express foreign genes in D. grandis include plasmid pZT23 and its derivatives. In this study, we developed a new system for the stable introduction and retention of expression plasmids for D. grandis. Two cryptic plasmids were removed from the wild-type strain to generate the TY3 strain. We then constructed a shuttle vector plasmid, pGRC5, containing the replication initiation region of the smallest cryptic plasmid, pDEGR-3, replication initiation region of the E. coli vector, pACYC184, and an antibiotic resistance gene. We introduced pGRC5, pZT23-derived plasmid pZT29H, and pI3-derived plasmid pRADN8 into strain TY3, and found their coexistence in D. grandis cells. The quantitative PCR assay results found that pGRC5, pZT29H, and pRADN8 had relative copy numbers of 11, 26, and 5 per genome, respectively. Furthermore, we developed a new plasmid in which the luciferase gene was controlled by the promoter region, which contained radiation-desiccation response operator sequences for D. grandis DdrO, a stress response regulon repressor in D. grandis, hence inducing gene expression via ultraviolet-C light irradiation. These plasmids are expected to facilitate the removal and production of toxic and valuable substances, in D. grandis, respectively, particularly of those involving multiple genes.
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Affiliation(s)
- Miyabi Sakai
- Department of Biotechnology and Life Science, Faculty of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Taichi Shimosaka
- Department of Life Sciences, Faculty of Life Sciences, Toyo University, Asaka, Japan
| | | | - Masafumi Yohda
- Department of Biotechnology and Life Science, Faculty of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Issay Narumi
- Department of Life Sciences, Faculty of Life Sciences, Toyo University, Asaka, Japan
- Graduate School of Life Sciences, Toyo University, Asaka, Japan
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2
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Otero-Olarra JE, Díaz-Cárdenas G, Aguilera-Arreola MG, Curiel-Quesada E, Pérez-Valdespino A. Aeromonas trota Is Highly Refractory to Acquire Exogenous Genetic Material. Microorganisms 2024; 12:1091. [PMID: 38930473 PMCID: PMC11206119 DOI: 10.3390/microorganisms12061091] [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: 04/30/2024] [Revised: 05/21/2024] [Accepted: 05/25/2024] [Indexed: 06/28/2024] Open
Abstract
Aeromonas trota is sensitive to most antibiotics and the sole species of this genus susceptible to ampicillin. This susceptibility profile could be related to its inability to acquire exogenous DNA. In this study, A. trota isolates were analyzed to establish their capacity to incorporate foreign DNA. Fourteen strains were identified as A. trota by multilocus phylogenetic analysis (MLPA). Minimal inhibitory concentrations of antibiotics (MIC) were assessed, confirming the susceptibility to most antibiotics tested. To explore their capacity to be transformed, A. trota strains were used as recipients in different horizontal transfer assays. Results showed that around fifty percent of A. trota strains were able to incorporate pBAMD1-2 and pBBR1MCS-3 plasmids after conjugal transfer. In all instances, conjugation frequencies were very low. Interestingly, several isoforms of plasmid pBBR1MCS-3 were observed in transconjugants. Strains could not receive pAr-32, a native plasmid from A. salmonicida. A. trota strains were unable to receive DNA by means of electroporation, natural transformation or vesiduction. These results confirm that A. trota species are extremely refractory to horizontal gene transfer, which could be associated to plasmid instability resulting from oligomerization or to the presence of defense systems against exogenous genetic material in their genomes. To explain the poor results of horizontal gene transfer (HGT), selected genomes were sequenced and analyzed, revealing the presence of defense systems, which could prevent the stable incorporation of exogenous DNA in A. trota.
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Affiliation(s)
- Jorge Erick Otero-Olarra
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás, Mexico City 11340, Mexico; (J.E.O.-O.); (G.D.-C.)
| | - Gilda Díaz-Cárdenas
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás, Mexico City 11340, Mexico; (J.E.O.-O.); (G.D.-C.)
| | - Ma Guadalupe Aguilera-Arreola
- Department of Microbiology, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás, Mexico City 11340, Mexico;
| | - Everardo Curiel-Quesada
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás, Mexico City 11340, Mexico; (J.E.O.-O.); (G.D.-C.)
| | - Abigail Pérez-Valdespino
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás, Mexico City 11340, Mexico; (J.E.O.-O.); (G.D.-C.)
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3
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de la Cruz M, Kunert F, Taymaz-Nikerel H, Sigala JC, Gosset G, Büchs J, Lara AR. Increasing the Pentose Phosphate Pathway Flux to Improve Plasmid DNA Production in Engineered E. coli. Microorganisms 2024; 12:150. [PMID: 38257977 PMCID: PMC10820320 DOI: 10.3390/microorganisms12010150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
The demand of plasmid DNA (pDNA) as a key element for gene therapy products, as well as mRNA and DNA vaccines, is increasing together with the need for more efficient production processes. An engineered E. coli strain lacking the phosphotransferase system and the pyruvate kinase A gene has been shown to produce more pDNA than its parental strain. With the aim of improving pDNA production in the engineered strain, several strategies to increase the flux to the pentose phosphate pathway (PPP) were evaluated. The simultaneous consumption of glucose and glycerol was a simple way to increase the growth rate, pDNA production rate, and supercoiled fraction (SCF). The overexpression of key genes from the PPP also improved pDNA production in glucose, but not in mixtures of glucose and glycerol. Particularly, the gene coding for the glucose 6-phosphate dehydrogenase (G6PDH) strongly improved the SCF, growth rate, and pDNA production rate. A linear relationship between the G6PDH activity and pDNA yield was found. A higher flux through the PPP was confirmed by flux balance analysis, which also estimates relevant differences in fluxes of the tricarboxylic acid cycle. These results are useful for developing further cell engineering strategies to increase pDNA production and quality.
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Affiliation(s)
- Mitzi de la Cruz
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Mexico City 05348, Mexico
| | - Flavio Kunert
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, 52074 Aachen, Germany
| | - Hilal Taymaz-Nikerel
- Department of Genetics and Bioengineering, Istanbul Bilgi University, 34060 Istanbul, Turkey
| | - Juan-Carlos Sigala
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Mexico City 05348, Mexico
| | - Guillermo Gosset
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
| | - Jochen Büchs
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, 52074 Aachen, Germany
| | - Alvaro R. Lara
- Department of Biological and Chemical Engineering, Aarhus University, 8000 Aarhus, Denmark
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4
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Loot C, Millot GA, Richard E, Littner E, Vit C, Lemoine F, Néron B, Cury J, Darracq B, Niault T, Lapaillerie D, Parissi V, Rocha EPC, Mazel D. Integron cassettes integrate into bacterial genomes via widespread non-classical attG sites. Nat Microbiol 2024; 9:228-240. [PMID: 38172619 DOI: 10.1038/s41564-023-01548-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 11/07/2023] [Indexed: 01/05/2024]
Abstract
Integrons are genetic elements involved in bacterial adaptation which capture, shuffle and express genes encoding adaptive functions embedded in cassettes. These events are governed by the integron integrase through site-specific recombination between attC and attI integron sites. Using computational and molecular genetic approaches, here we demonstrate that the integrase also catalyses cassette integration into bacterial genomes outside of its known att sites. Once integrated, these cassettes can be expressed if located near bacterial promoters and can be excised at the integration point or outside, inducing chromosomal modifications in the latter case. Analysis of more than 5 × 105 independent integration events revealed a very large genomic integration landscape. We identified consensus recombination sequences, named attG sites, which differ greatly in sequence and structure from classical att sites. These results unveil an alternative route for dissemination of adaptive functions in bacteria and expand the role of integrons in bacterial evolution.
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Affiliation(s)
- Céline Loot
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Unité Plasticité du Génome Bactérien, Paris, France.
| | - Gael A Millot
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Egill Richard
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Unité Plasticité du Génome Bactérien, Paris, France
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Eloi Littner
- Sorbonne Université, Collège Doctoral, Paris, France
- DGA CBRN Defence, Vert-le-Petit, France
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Microbial Evolutionary Genomics, Paris, France
| | - Claire Vit
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Unité Plasticité du Génome Bactérien, Paris, France
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Frédéric Lemoine
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Bertrand Néron
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Jean Cury
- Université Paris-Saclay, Inria, Laboratoire de Recherche en Informatique, CNRS UMR 8623, Orsay, France
| | - Baptiste Darracq
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Unité Plasticité du Génome Bactérien, Paris, France
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Théophile Niault
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Unité Plasticité du Génome Bactérien, Paris, France
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Delphine Lapaillerie
- Université de Bordeaux, Fundamental Microbiology and Pathogenicity Laboratory, CNRS UMR 5234, Département de Sciences Biologiques et Médicales, Bordeaux, France
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), Bordeaux, France
| | - Vincent Parissi
- Université de Bordeaux, Fundamental Microbiology and Pathogenicity Laboratory, CNRS UMR 5234, Département de Sciences Biologiques et Médicales, Bordeaux, France
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), Bordeaux, France
| | - Eduardo P C Rocha
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Microbial Evolutionary Genomics, Paris, France
| | - Didier Mazel
- Institut Pasteur, Université Paris Cité, CNRS UMR 3525, Unité Plasticité du Génome Bactérien, Paris, France
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5
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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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6
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Dewan I, Uecker H. A mathematician's guide to plasmids: an introduction to plasmid biology for modellers. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001362. [PMID: 37505810 PMCID: PMC10433428 DOI: 10.1099/mic.0.001362] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023]
Abstract
Plasmids, extrachromosomal DNA molecules commonly found in bacterial and archaeal cells, play an important role in bacterial genetics and evolution. Our understanding of plasmid biology has been furthered greatly by the development of mathematical models, and there are many questions about plasmids that models would be useful in answering. In this review, we present an introductory, yet comprehensive, overview of the biology of plasmids suitable for modellers unfamiliar with plasmids who want to get up to speed and to begin working on plasmid-related models. In addition to reviewing the diversity of plasmids and the genes they carry, their key physiological functions, and interactions between plasmid and host, we also highlight selected plasmid topics that may be of particular interest to modellers and areas where there is a particular need for theoretical development. The world of plasmids holds a great variety of subjects that will interest mathematical biologists, and introducing new modellers to the subject will help to expand the existing body of plasmid theory.
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Affiliation(s)
- Ian Dewan
- Research Group Stochastic Evolutionary Dynamics, Department of Theoretical Biology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Hildegard Uecker
- Research Group Stochastic Evolutionary Dynamics, Department of Theoretical Biology, Max Planck Institute for Evolutionary Biology, Plön, Germany
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7
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Siguier P, Rousseau P, Cornet F, Chandler M. A subclass of the IS1202 family of bacterial insertion sequences targets XerCD recombination sites. Plasmid 2023; 127:102696. [PMID: 37302728 DOI: 10.1016/j.plasmid.2023.102696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 06/13/2023]
Abstract
We describe here a new family of IS which are related to IS1202, originally isolated from Streptococcus pneumoniae in the mid-1990s and previously tagged as an emerging IS family in the ISfinder database. Members of this family have impacted some important properties of their hosts. We describe here another potentially important property of certain family members: specific targeting of xrs recombination sites. The family could be divided into three subgroups based on their transposase sequences and the length on the target repeats (DR) they generate on insertion: subgroup IS1202 (24-29 bp); ISTde1 (15-18 bp); and ISAba32 (5-6 bp). Members of the ISAba32 subgroup were repeatedly found abutting Xer recombinase recombination sites (xrs), separated by an intervening copy of a DR. These xrs sites, present in multiple copies in a number of Acinetobacter plasmids flanking antibiotic resistance genes, were proposed to form a new type of mobile genetic element using the chromosomally-encoded XerCD recombinase for mobility. Transposase alignments identified subgroup-specific indels which may be responsible for the differences in the transposition properties of the three subgroups (i.e. DR length and target specificity). We propose that this collection of IS be classed as a new insertion sequence family: the IS1202 family composed of three subgroups, only one of which specifically targets plasmid-borne xrs. We discuss the implications of xrs targeting for gene mobility.
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Affiliation(s)
- Patricia Siguier
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, France.
| | - Philippe Rousseau
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, France
| | - François Cornet
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, France
| | - Michael Chandler
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC, USA.
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Giacone L, Cameranesi MM, Sanchez RI, Limansky AS, Morán-Barrio J, Viale AM. Dynamic state of plasmid genomic architectures resulting from XerC/D-mediated site-specific recombination in Acinetobacter baumannii Rep_3 superfamily resistance plasmids carrying blaOXA-58 - and Tn aphA6-resistance modules. Front Microbiol 2023; 14:1057608. [PMID: 36846794 PMCID: PMC9947245 DOI: 10.3389/fmicb.2023.1057608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/04/2023] [Indexed: 02/11/2023] Open
Abstract
The acquisition of bla OXA genes encoding different carbapenem-hydrolyzing class-D β-lactamases (CHDL) represents a main determinant of carbapenem resistance in the nosocomial pathogen Acinetobacter baumannii. The blaOXA-58 gene, in particular, is generally embedded in similar resistance modules (RM) carried by plasmids unique to the Acinetobacter genus lacking self-transferability. The ample variations in the immediate genomic contexts in which blaOXA-58 -containing RMs are inserted among these plasmids, and the almost invariable presence at their borders of non-identical 28-bp sequences potentially recognized by the host XerC and XerD tyrosine recombinases (pXerC/D-like sites), suggested an involvement of these sites in the lateral mobilization of the gene structures they encircle. However, whether and how these pXerC/D sites participate in this process is only beginning to be understood. Here, we used a series of experimental approaches to analyze the contribution of pXerC/D-mediated site-specific recombination to the generation of structural diversity between resistance plasmids carrying pXerC/D-bounded bla OXA-58- and TnaphA6-containing RM harbored by two phylogenetically- and epidemiologically-closely related A. baumannii strains of our collection, Ab242 and Ab825, during adaptation to the hospital environment. Our analysis disclosed the existence of different bona fide pairs of recombinationally-active pXerC/D sites in these plasmids, some mediating reversible intramolecular inversions and others reversible plasmid fusions/resolutions. All of the identified recombinationally-active pairs shared identical GGTGTA sequences at the cr spacer separating the XerC- and XerD-binding regions. The fusion of two Ab825 plasmids mediated by a pair of recombinationally-active pXerC/D sites displaying sequence differences at the cr spacer could be inferred on the basis of sequence comparison analysis, but no evidence of reversibility could be obtained in this case. The reversible plasmid genome rearrangements mediated by recombinationally-active pairs of pXerC/D sites reported here probably represents an ancient mechanism of generating structural diversity in the Acinetobacter plasmid pool. This recursive process could facilitate a rapid adaptation of an eventual bacterial host to changing environments, and has certainly contributed to the evolution of Acinetobacter plasmids and the capture and dissemination of bla OXA-58 genes among Acinetobacter and non-Acinetobacter populations co-residing in the hospital niche.
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Affiliation(s)
| | | | - Rocío I. Sanchez
- Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Adriana S. Limansky
- Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario (UNR), Rosario, Argentina
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9
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Dheekollu J, Wiedmer A, Ayyanathan K, Deakyne JS, Messick TE, Lieberman PM. Cell-cycle-dependent EBNA1-DNA crosslinking promotes replication termination at oriP and viral episome maintenance. Cell 2021; 184:643-654.e13. [PMID: 33482082 DOI: 10.1016/j.cell.2020.12.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/17/2020] [Accepted: 12/15/2020] [Indexed: 02/08/2023]
Abstract
Epstein-Barr virus (EBV) is an oncogenic human herpesvirus that persists as a multicopy episome in proliferating host cells. Episome maintenance is strictly dependent on EBNA1, a sequence-specific DNA-binding protein with no known enzymatic activities. Here, we show that EBNA1 forms a cell cycle-dependent DNA crosslink with the EBV origin of plasmid replication oriP. EBNA1 tyrosine 518 (Y518) is essential for crosslinking to oriP and functionally required for episome maintenance and generation of EBV-transformed lymphoblastoid cell lines (LCLs). Mechanistically, Y518 is required for replication fork termination at oriP in vivo and for formation of SDS-resistant complexes in vitro. EBNA1-DNA crosslinking corresponds to single-strand endonuclease activity specific to DNA structures enriched at replication-termination sites, such as 4-way junctions. These findings reveal that EBNA1 forms tyrosine-dependent DNA-protein crosslinks and single-strand cleavage at oriP required for replication termination and viral episome maintenance.
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10
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An improved Xer-cise technology for the generation of multiple unmarked mutants in Mycobacteria. Biotechniques 2020; 68:106-110. [PMID: 31937110 DOI: 10.2144/btn-2019-0119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Xer-cise is a technique using antibiotic resistance cassettes flanked by dif sites allowing spontaneous and accurate excision from bacterial chromosomes with a high frequency through the action of the cellular recombinase XerCD. Here, we report a significant improvement of Xer-cise in Mycobacteria. Zeocin resistance cassettes flanked by variants of the natural Mycobacterium tuberculosis dif site were constructed and shown to be effective tools to construct multiple unmarked mutations in M. tuberculosis and in the model species Mycobacterium smegmatis. The dif site variants harbor mutations in the central region and can therefore not recombine with the wild-type or other variants, resulting in mutants of increased genetic stability. The herein described method should be generalizable to virtually any transformable bacterial species.
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11
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Emergence of plasmid stability under non-selective conditions maintains antibiotic resistance. Nat Commun 2019; 10:2595. [PMID: 31197163 PMCID: PMC6565834 DOI: 10.1038/s41467-019-10600-7] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/21/2019] [Indexed: 01/21/2023] Open
Abstract
Plasmid acquisition is an important mechanism of rapid adaptation and niche expansion in prokaryotes. Positive selection for plasmid-coded functions is a major driver of plasmid evolution, while plasmids that do not confer a selective advantage are considered costly and expected to go extinct. Yet, plasmids are ubiquitous in nature, and their persistence remains an evolutionary paradox. Here, we demonstrate that non-mobile plasmids persist over evolutionary timescales without selection for the plasmid function. Evolving a minimal plasmid encoding for antibiotics resistance in Escherichia coli, we discover that plasmid stability emerges in the absence of antibiotics and that plasmid loss is determined by transcription-replication conflicts. We further find that environmental conditions modulate these conflicts and plasmid persistence. Silencing the transcription of the resistance gene results in stable plasmids that become fixed in the population. Evolution of plasmid stability under non-selective conditions provides an evolutionary explanation for the ubiquity of plasmids in nature. It is expected that plasmids are costly and therefore that selection is required to maintain them within bacterial populations. Here, Wein et al. show that plasmid stability can emerge even in the absence of positive selection and that loss may be determined by transcription-replication conflict.
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Timilsina S, Pereira-Martin JA, Minsavage GV, Iruegas-Bocardo F, Abrahamian P, Potnis N, Kolaczkowski B, Vallad GE, Goss EM, Jones JB. Multiple Recombination Events Drive the Current Genetic Structure of Xanthomonas perforans in Florida. Front Microbiol 2019; 10:448. [PMID: 30930868 PMCID: PMC6425879 DOI: 10.3389/fmicb.2019.00448] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/20/2019] [Indexed: 11/23/2022] Open
Abstract
Prior to the identification of Xanthomonas perforans associated with bacterial spot of tomato in 1991, X. euvesicatoria was the only known species in Florida. Currently, X. perforans is the Xanthomonas sp. associated with tomato in Florida. Changes in pathogenic race and sequence alleles over time signify shifts in the dominant X. perforans genotype in Florida. We previously reported recombination of X. perforans strains with closely related Xanthomonas species as a potential driving factor for X. perforans evolution. However, the extent of recombination across the X. perforans genomes was unknown. We used a core genome multilocus sequence analysis approach to identify conserved genes and evaluated recombination-associated evolution of these genes in X. perforans. A total of 1,356 genes were determined to be "core" genes conserved among the 58 X. perforans genomes used in the study. Our approach identified three genetic groups of X. perforans in Florida based on the principal component analysis (PCA) using core genes. Nucleotide variation in 241 genes defined these groups, that are referred as Phylogenetic-group Defining (PgD) genes. Furthermore, alleles of many of these PgD genes showed 100% sequence identity with X. euvesicatoria, suggesting that variation likely has been introduced by recombination at multiple locations throughout the bacterial chromosome. Site-specific recombinase genes along with plasmid mobilization and phage associated genes were observed at different frequencies in the three phylogenetic groups and were associated with clusters of recombinant genes. Our analysis of core genes revealed the extent, source, and mechanisms of recombination events that shaped the current population and genomic structure of X. perforans in Florida.
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Affiliation(s)
- Sujan Timilsina
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | | | - Gerald V. Minsavage
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | | | - Peter Abrahamian
- Gulf Coast Research and Education Center, University of Florida, Gainesville, FL, United States
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Bryan Kolaczkowski
- Microbiology and Cell Science, University of Florida, Gainesville, FL, United States
| | - Gary E. Vallad
- Gulf Coast Research and Education Center, University of Florida, Gainesville, FL, United States
| | - Erica M. Goss
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
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Partridge SR, Kwong SM, Firth N, Jensen SO. Mobile Genetic Elements Associated with Antimicrobial Resistance. Clin Microbiol Rev 2018; 31:e00088-17. [PMID: 30068738 PMCID: PMC6148190 DOI: 10.1128/cmr.00088-17] [Citation(s) in RCA: 1159] [Impact Index Per Article: 193.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Strains of bacteria resistant to antibiotics, particularly those that are multiresistant, are an increasing major health care problem around the world. It is now abundantly clear that both Gram-negative and Gram-positive bacteria are able to meet the evolutionary challenge of combating antimicrobial chemotherapy, often by acquiring preexisting resistance determinants from the bacterial gene pool. This is achieved through the concerted activities of mobile genetic elements able to move within or between DNA molecules, which include insertion sequences, transposons, and gene cassettes/integrons, and those that are able to transfer between bacterial cells, such as plasmids and integrative conjugative elements. Together these elements play a central role in facilitating horizontal genetic exchange and therefore promote the acquisition and spread of resistance genes. This review aims to outline the characteristics of the major types of mobile genetic elements involved in acquisition and spread of antibiotic resistance in both Gram-negative and Gram-positive bacteria, focusing on the so-called ESKAPEE group of organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli), which have become the most problematic hospital pathogens.
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Affiliation(s)
- Sally R Partridge
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, New South Wales, Australia
| | - Stephen M Kwong
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Neville Firth
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Slade O Jensen
- Microbiology and Infectious Diseases, School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- Antibiotic Resistance & Mobile Elements Group, Ingham Institute for Applied Medical Research, Sydney, New South Wales, Australia
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Castillo F, Benmohamed A, Szatmari G. Xer Site Specific Recombination: Double and Single Recombinase Systems. Front Microbiol 2017; 8:453. [PMID: 28373867 PMCID: PMC5357621 DOI: 10.3389/fmicb.2017.00453] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/03/2017] [Indexed: 12/20/2022] Open
Abstract
The separation and segregation of newly replicated bacterial chromosomes can be constrained by the formation of circular chromosome dimers caused by crossing over during homologous recombination events. In Escherichia coli and most bacteria, dimers are resolved to monomers by site-specific recombination, a process performed by two Chromosomally Encoded tyrosine Recombinases (XerC and XerD). XerCD recombinases act at a 28 bp recombination site dif, which is located at the replication terminus region of the chromosome. The septal protein FtsK controls the initiation of the dimer resolution reaction, so that recombination occurs at the right time (immediately prior to cell division) and at the right place (cell division septum). XerCD and FtsK have been detected in nearly all sequenced eubacterial genomes including Proteobacteria, Archaea, and Firmicutes. However, in Streptococci and Lactococci, an alternative system has been found, composed of a single recombinase (XerS) genetically linked to an atypical 31 bp recombination site (difSL). A similar recombination system has also been found in 𝜀-proteobacteria such as Campylobacter and Helicobacter, where a single recombinase (XerH) acts at a resolution site called difH. Most Archaea contain a recombinase called XerA that acts on a highly conserved 28 bp sequence dif, which appears to act independently of FtsK. Additionally, several mobile elements have been found to exploit the dif/Xer system to integrate their genomes into the host chromosome in Vibrio cholerae, Neisseria gonorrhoeae, and Enterobacter cloacae. This review highlights the versatility of dif/Xer recombinase systems in prokaryotes and summarizes our current understanding of homologs of dif/Xer machineries.
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Affiliation(s)
- Fabio Castillo
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, MontréalQC, Canada
| | | | - George Szatmari
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, MontréalQC, Canada
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The IntXO-PSL Recombination System Is a Key Component of the Second Maintenance System for Bacillus anthracis Plasmid pXO1. J Bacteriol 2016; 198:1939-1951. [PMID: 27137503 DOI: 10.1128/jb.01004-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED We previously identified three noncontiguous regions on Bacillus anthracis plasmid pXO1 that comprise a system for accurate plasmid partitioning and maintenance. However, deletion of these regions did not decrease retention of certain shortened pXO1 plasmids during vegetative growth. Using two genetic tools developed for DNA manipulation in B. anthracis (the Cre-loxP and Flp-FRT systems), we found two other noncontiguous pXO1 regions that together are sufficient for plasmid stability. This second pXO1 maintenance system includes the tubZ and tubR genes, characteristic of a type III partitioning system, and the IntXO recombinase gene (GBAA_RS29165), encoding a tyrosine recombinase, along with its adjacent 37-bp perfect stem-loop (PSL) target. Insertion of either the tubZ and tubR genes or the IntXO-PSL system into an unstable mini-pXO1 plasmid did not restore plasmid stability. The need for the two components of the second pXO1 maintenance system follows from the sequential roles of IntXO-PSL in generating monomeric circular daughter pXO1 molecules (thereby presumably preventing dimer catastrophe) and of TubZ/TubR in partitioning the monomers during cell division. We show that the IntXO recombinase deletes DNA regions located between two PSL sites in a manner similar to the actions of the Cre-loxP and Flp-FRT systems. IMPORTANCE Tyrosine recombinases catalyze cutting and joining reactions between short specific DNA sequences. Three types of reactions occur: integration and excision of DNA segments, inversion of DNA segments, and separation of monomeric forms from replicating circular DNA molecules. Here we show that the newly discovered site-specific IntXO-PSL recombinase system that contributes to the maintenance of the B. anthracis plasmid pXO1 can be used for genome engineering in a manner similar to that of the Cre-loxP or Flp-FRT system.
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FtsK translocation permits discrimination between an endogenous and an imported Xer/dif recombination complex. Proc Natl Acad Sci U S A 2016; 113:7882-7. [PMID: 27317749 DOI: 10.1073/pnas.1523178113] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In bacteria, the FtsK/Xer/dif (chromosome dimer resolution site) system is essential for faithful vertical genetic transmission, ensuring the resolution of chromosome dimers during their segregation to daughter cells. This system is also targeted by mobile genetic elements that integrate into chromosomal dif sites. A central question is thus how Xer/dif recombination is tuned to both act in chromosome segregation and stably maintain mobile elements. To explore this question, we focused on pathogenic Neisseria species harboring a genomic island in their dif sites. We show that the FtsK DNA translocase acts differentially at the recombination sites flanking the genomic island. It stops at one Xer/dif complex, activating recombination, but it does not stop on the other site, thus dismantling it. FtsK translocation thus permits cis discrimination between an endogenous and an imported Xer/dif recombination complex.
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