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Foley SL, Kaldhone PR, Ricke SC, Han J. Incompatibility Group I1 (IncI1) Plasmids: Their Genetics, Biology, and Public Health Relevance. Microbiol Mol Biol Rev 2021; 85:e00031-20. [PMID: 33910982 PMCID: PMC8139525 DOI: 10.1128/mmbr.00031-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bacterial plasmids are extrachromosomal genetic elements that often carry antimicrobial resistance (AMR) genes and genes encoding increased virulence and can be transmissible among bacteria by conjugation. One key group of plasmids is the incompatibility group I1 (IncI1) plasmids, which have been isolated from multiple Enterobacteriaceae of food animal origin and clinically ill human patients. The IncI group of plasmids were initially characterized due to their sensitivity to the filamentous bacteriophage If1. Two prototypical IncI1 plasmids, R64 and pColIb-P9, have been extensively studied, and the plasmids consist of unique regions associated with plasmid replication, plasmid stability/maintenance, transfer machinery apparatus, single-stranded DNA transfer, and antimicrobial resistance. IncI1 plasmids are somewhat unique in that they encode two types of sex pili, a thick, rigid pilus necessary for mating and a thin, flexible pilus that helps stabilize bacteria for plasmid transfer in liquid environments. A key public health concern with IncI1 plasmids is their ability to carry antimicrobial resistance genes, including those associated with critically important antimicrobials used to treat severe cases of enteric infections, including the third-generation cephalosporins. Because of the potential importance of these plasmids, this review focuses on the distribution of the plasmids, their phenotypic characteristics associated with antimicrobial resistance and virulence, and their replication, maintenance, and transfer.
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Affiliation(s)
- Steven L Foley
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Pravin R Kaldhone
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
- Center for Food Safety and Food Science Department, University of Arkansas, Fayetteville, Arkansas, USA
| | - Steven C Ricke
- Meat Science & Animal Biologics Discovery Program, Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin, USA
| | - Jing Han
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
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2
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Nyong EC, Zaia SR, Allué-Guardia A, Rodriguez AL, Irion-Byrd Z, Koenig SSK, Feng P, Bono JL, Eppinger M. Pathogenomes of Atypical Non-shigatoxigenic Escherichia coli NSF/SF O157:H7/NM: Comprehensive Phylogenomic Analysis Using Closed Genomes. Front Microbiol 2020; 11:619. [PMID: 32351476 PMCID: PMC7175801 DOI: 10.3389/fmicb.2020.00619] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
The toxigenic conversion of Escherichia coli strains by Shiga toxin-converting (Stx) bacteriophages were prominent and recurring events in the stepwise evolution of enterohemorrhagic E. coli (EHEC) O157:H7 from an enteropathogenic (EPEC) O55:H7 ancestor. Atypical, attenuated isolates have been described for both non-sorbitol fermenting (NSF) O157:H7 and SF O157:NM serotypes, which are distinguished by the absence of Stx, the characteristic virulence hallmark of Stx-producing E. coli (STEC). Such atypical isolates either never acquired Stx-phages or may have secondarily lost stx during the course of infection, isolation, or routine subculture; the latter are commonly referred to as LST (Lost Shiga Toxin)-isolates. In this study we analyzed the genomes of 15 NSF O157:H7 and SF O157:NM strains from North America, Europe, and Asia that are characterized by the absence of stx, the virulence hallmark of STEC. The individual genomic basis of the Stx (-) phenotype has remained largely undetermined as the majority of STEC genomes in public genome repositories were generated using short read technology and are in draft stage, posing a major obstacle for the high-resolution whole genome sequence typing (WGST). The application of LRT (long-read technology) sequencing provided us with closed genomes, which proved critical to put the atypical non-shigatoxigenic NSF O157:H7 and SF O157:NM strains into the phylogenomic context of the stepwise evolutionary model. Availability of closed chromosomes for representative Stx (-) NSF O157:H7 and SF O157:NM strains allowed to describe the genomic basis and individual evolutionary trajectories underlying the absence of Stx at high accuracy and resolution. The ability of LRT to recover and accurately assemble plasmids revealed a strong correlation between the strains' featured plasmid genotype and chromosomally inferred clade, which suggests the coevolution of the chromosome and accessory plasmids. The identified ancestral traits in the pSFO157 plasmid of NSF O157:H7 strain LSU-61 provided additional evidence for its intermediate status. Taken together, these observations highlight the utility of LRTs for advancing our understanding of EHEC O157:H7/NM pathogenome evolution. Insights into the genomic and phenotypic plasticity of STEC on a lineage- and genome-wide scale are foundational to improve and inform risk assessment, biosurveillance, and prevention strategies.
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Affiliation(s)
- Emmanuel C. Nyong
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Sam R. Zaia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Anna Allué-Guardia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Armando L. Rodriguez
- Research Computing Support Group, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Zaina Irion-Byrd
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Sara S. K. Koenig
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | | | - James L. Bono
- United States Meat Animal Research Center, Agricultural Research Service, United States Department of Agriculture (ARS-USDA), Clay Center, NE, United States
| | - Mark Eppinger
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
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3
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Mo SS, Telke AA, Osei KO, Sekse C, Slettemeås JS, Urdahl AM, Ilag HK, Leangapichart T, Sunde M. bla CTX-M- 1/IncI1-Iγ Plasmids Circulating in Escherichia coli From Norwegian Broiler Production Are Related, but Distinguishable. Front Microbiol 2020; 11:333. [PMID: 32194533 PMCID: PMC7066084 DOI: 10.3389/fmicb.2020.00333] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/17/2020] [Indexed: 01/04/2023] Open
Abstract
Escherichia coli carrying blaCTX–M–1 mediating resistance to extended-spectrum cephalosporins was recently described as a new genotype in Norwegian broiler production. The aim of this study was to characterize these isolates (n = 31) in order to determine whether the emergence of the genotype was caused by clonal expansion or horizontal dissemination of blaCTX–M–1-carrying plasmids. All included isolates were subjected to whole genome sequencing. Plasmid transferability was determined by conjugation, and plasmid replicons in the transconjugants were described using PCR-based replicon typing. Plasmid sizes were determined using S1 nuclease digestion. Plasmids in a subset of strains were reconstructed and compared to plasmids from broiler production in other European countries. The isolates belonged to nine different sequence types (STs), with the largest group being ST57 (n = 12). The vast majority of blaCTX–M–1-carrying plasmids were conjugative. All transconjugants were positive for the IncI1-Iγ replicon, and several also harbored the IncFIB replicon. Highly similar plasmids were present in different E. coli STs. Additionally, high similarity to previously published plasmids was detected. A reconstructed plasmid from an ST57 isolate harbored both IncI1-Iγ and IncFIB replicons and was considered to be co-integrated. The presence of one large plasmid was confirmed by S1 nuclease digestion. Our results show that dissemination of blaCTX–M–1 in Norwegian broiler production is due to both clonal expansion and horizontal transfer of plasmids carrying blaCTX–M–1. The blaCTX–M–1/IncI1-Iγ plasmids grouped into two main lineages, namely clonal complex (CC)-3 and CC-7. The genetic diversity at both strain and plasmid level indicates multiple introductions to Norway. We also show that the blaCTX–M–1 plasmids circulating in Norwegian broiler production are highly similar to plasmids previously described in other countries.
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Affiliation(s)
- Solveig Sølverød Mo
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway
| | - Amar Anandrao Telke
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway
| | - Kingsley Oteng Osei
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway.,Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Camilla Sekse
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway
| | - Jannice Schau Slettemeås
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway
| | - Anne Margrete Urdahl
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway
| | - Hanna Karin Ilag
- Section for Microbiology, Department of Analysis and Diagnostics, Norwegian Veterinary Institute, Oslo, Norway
| | - Thongpan Leangapichart
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway
| | - Marianne Sunde
- Section for Food Safety and Animal Health Research, Department of Animal Helath, Welfare and Food Safety, Norwegian Veterinary Institute, Oslo, Norway
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Carattoli A, Villa L, Fortini D, García-Fernández A. Contemporary IncI1 plasmids involved in the transmission and spread of antimicrobial resistance in Enterobacteriaceae. Plasmid 2018; 118:102392. [PMID: 30529488 DOI: 10.1016/j.plasmid.2018.12.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 11/22/2018] [Accepted: 12/05/2018] [Indexed: 10/27/2022]
Abstract
IncI1 has become one of the most common plasmid families in contemporary Enterobacteriaceae from both human and animal sources. In clinical epidemiology, this plasmid type ranks first as the confirmed vehicle of transmission of extended spectrum beta-lactamase and plasmid AmpC genes in isolates from food-producing animals. In this review, we describe the epidemiology and evolution of IncI1 plasmids and closely related IncIγ plasmids. We highlight the emergence of epidemic plasmids circulating among different bacterial hosts in geographically distant countries, and we address the phylogeny of the IncI1 and IncIγ family based on plasmid Multilocus Sequence Typing.
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Affiliation(s)
- Alessandra Carattoli
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Laura Villa
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Daniela Fortini
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Aurora García-Fernández
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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Poidevin M, Sato M, Altinoglu I, Delaplace M, Sato C, Yamaichi Y. Mutation in ESBL Plasmid from Escherichia coli O104:H4 Leads Autoagglutination and Enhanced Plasmid Dissemination. Front Microbiol 2018; 9:130. [PMID: 29456528 PMCID: PMC5801416 DOI: 10.3389/fmicb.2018.00130] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 01/18/2018] [Indexed: 12/02/2022] Open
Abstract
Conjugative plasmids are one of the main driving force of wide-spreading of multidrug resistance (MDR) bacteria. They are self-transmittable via conjugation as carrying the required set of genes and cis-acting DNA locus for direct cell-to-cell transfer. IncI incompatibility plasmids are nowadays often associated with extended-spectrum beta-lactamases producing Enterobacteria in clinic and environment. pESBL-EA11 was isolated from Escherichia coli O104:H4 outbreak strain in Germany in 2011. During the previous study identifying transfer genes of pESBL-EA11, it was shown that transposon insertion at certain DNA region of the plasmid, referred to as Hft, resulted in great enhancement of transfer ability. This suggested that genetic modifications can enhance dissemination of MDR plasmids. Such ‘superspreader’ mutations have attracted little attention so far despite their high potential to worsen MDR spreading. Present study aimed to gain our understanding on regulatory elements that involved pESBL transfer. While previous studies of IncI plasmids indicated that immediate downstream gene of Hft, traA, is not essential for conjugative transfer, here we showed that overexpression of TraA in host cell elevated transfer rate of pESBL-EA11. Transposon insertion or certain nucleotide substitutions in Hft led strong TraA overexpression which resulted in activation of essential regulator TraB and likely overexpression of conjugative pili. Atmospheric Scanning Electron Microscopy observation suggested that IncI pili are distinct from other types of conjugative pili (such as long filamentous F-type pili) and rather expressed throughout the cell surface. High transfer efficiency in the mutant pESBL-EA11 was involved with hyperpiliation which facilitates cell-to-cell adhesion, including autoagglutination. The capability of plasmids to evolve to highly transmissible mutant is alarming, particularly it might also have adverse effect on host pathogenicity.
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Affiliation(s)
- Mickaël Poidevin
- Institute for Integrative Biology of the Cell, Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France
| | - Mari Sato
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Ipek Altinoglu
- Institute for Integrative Biology of the Cell, Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.,Graduate School of Structure and Dynamics of Living Systems, Université Paris-Sud, Orsay, France
| | - Manon Delaplace
- Institute for Integrative Biology of the Cell, Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.,Master of Science and Technology, University Pierre and Marie Curie, Paris, France
| | - Chikara Sato
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Yoshiharu Yamaichi
- Institute for Integrative Biology of the Cell, Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France
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6
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Aviv G, Rahav G, Gal-Mor O. Horizontal Transfer of the Salmonella enterica Serovar Infantis Resistance and Virulence Plasmid pESI to the Gut Microbiota of Warm-Blooded Hosts. mBio 2016; 7:e01395-16. [PMID: 27601577 PMCID: PMC5013300 DOI: 10.1128/mbio.01395-16] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Salmonella enterica serovar Infantis is one of the prevalent salmonellae worldwide. Recently, we showed that the emergence of S Infantis in Israel was facilitated by the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Here we elucidate the ecology, transmission properties, and regulation of pESI. We show that despite its large size (~280 kb), pESI does not impose a significant metabolic burden in vitro and that it has been recently fixed in the domestic S Infantis population. pESI conjugation and the transcription of its pilus (pil) genes are inhibited at the ambient temperature (27°C) and by ≥1% bile but increased under temperatures of 37 to 41°C, oxidative stress, moderate osmolarity, and the microaerobic conditions characterizing the intestinal environment of warm-blooded animals. The pESI-encoded protein TraB and the oxygen homeostasis regulator Fnr were identified as transcriptional regulators of pESI conjugation. Using the mouse model, we show that following S Infantis infection, pESI can be horizontally transferred to the gut microbiota, including to commensal Escherichia coli strains. Possible transfer, but not persistence, of pESI was also observed into Gram-positive mouse microbiota species, especially Lactobacillus reuteri Moreover, pESI was demonstrated to further disseminate from gut microbiota to S. enterica serovar Typhimurium, in the context of gastrointestinal infection. These findings exhibit the ability of a selfish clinically relevant megaplasmid to distribute to and from the microbiota and suggest an overlooked role of the microbiota as a reservoir of mobile genetic elements and intermediator in the spread of resistance and virulence genes between commensals and pathogenic bacteria. IMPORTANCE Plasmid conjugation plays a key role in microbial evolution, enabling the acquisition of new phenotypes, including resistance and virulence. Salmonella enterica serovar Infantis is one of the ubiquitous salmonellae worldwide and a major cause of foodborne infections. Previously, we showed that the emergence of S Infantis in Israel has involved the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Recently, the emergence of another S Infantis strain carrying a pESI-like plasmid was identified in Italy, suggesting that the acquisition of pESI may be common to different emergent S Infantis populations globally. Transmission of this plasmid to other strains or bacterial species is an alarming scenario. Understanding the ecology, regulation, and transmission properties of clinically relevant plasmids and the role of the microbiota in their spreading offers a new mechanism explaining the emergence of new pathogenic and resistant biotypes and may assist in the development of appropriate surveillance and prevention measures.
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Affiliation(s)
- Gili Aviv
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Galia Rahav
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ohad Gal-Mor
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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7
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Horizontal Transfer of the Salmonella enterica Serovar Infantis Resistance and Virulence Plasmid pESI to the Gut Microbiota of Warm-Blooded Hosts. mBio 2016. [PMID: 27601577 DOI: 10.1128/mbio.01395‐16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Salmonella enterica serovar Infantis is one of the prevalent salmonellae worldwide. Recently, we showed that the emergence of S Infantis in Israel was facilitated by the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Here we elucidate the ecology, transmission properties, and regulation of pESI. We show that despite its large size (~280 kb), pESI does not impose a significant metabolic burden in vitro and that it has been recently fixed in the domestic S Infantis population. pESI conjugation and the transcription of its pilus (pil) genes are inhibited at the ambient temperature (27°C) and by ≥1% bile but increased under temperatures of 37 to 41°C, oxidative stress, moderate osmolarity, and the microaerobic conditions characterizing the intestinal environment of warm-blooded animals. The pESI-encoded protein TraB and the oxygen homeostasis regulator Fnr were identified as transcriptional regulators of pESI conjugation. Using the mouse model, we show that following S Infantis infection, pESI can be horizontally transferred to the gut microbiota, including to commensal Escherichia coli strains. Possible transfer, but not persistence, of pESI was also observed into Gram-positive mouse microbiota species, especially Lactobacillus reuteri Moreover, pESI was demonstrated to further disseminate from gut microbiota to S. enterica serovar Typhimurium, in the context of gastrointestinal infection. These findings exhibit the ability of a selfish clinically relevant megaplasmid to distribute to and from the microbiota and suggest an overlooked role of the microbiota as a reservoir of mobile genetic elements and intermediator in the spread of resistance and virulence genes between commensals and pathogenic bacteria. IMPORTANCE Plasmid conjugation plays a key role in microbial evolution, enabling the acquisition of new phenotypes, including resistance and virulence. Salmonella enterica serovar Infantis is one of the ubiquitous salmonellae worldwide and a major cause of foodborne infections. Previously, we showed that the emergence of S Infantis in Israel has involved the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Recently, the emergence of another S Infantis strain carrying a pESI-like plasmid was identified in Italy, suggesting that the acquisition of pESI may be common to different emergent S Infantis populations globally. Transmission of this plasmid to other strains or bacterial species is an alarming scenario. Understanding the ecology, regulation, and transmission properties of clinically relevant plasmids and the role of the microbiota in their spreading offers a new mechanism explaining the emergence of new pathogenic and resistant biotypes and may assist in the development of appropriate surveillance and prevention measures.
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8
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Yamaichi Y, Chao MC, Sasabe J, Clark L, Davis BM, Yamamoto N, Mori H, Kurokawa K, Waldor MK. High-resolution genetic analysis of the requirements for horizontal transmission of the ESBL plasmid from Escherichia coli O104:H4. Nucleic Acids Res 2015; 43:348-60. [PMID: 25477379 PMCID: PMC4288162 DOI: 10.1093/nar/gku1262] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/12/2014] [Accepted: 11/17/2014] [Indexed: 12/20/2022] Open
Abstract
Horizontal dissemination of the genes encoding extended spectrum beta-lactamases (ESBLs) via conjugative plasmids is facilitating the increasingly widespread resistance of pathogens to beta-lactam antibiotics. However, there is relatively little known about the regulatory factors and mechanisms that govern the spread of these plasmids. Here, we carried out a high-throughput, transposon insertion site sequencing analysis (TnSeq) to identify genes that enable the maintenance and transmission of pESBL, an R64 (IncI1)-related resistance plasmid that was isolated from Escherichia coli O104:H4 linked to a recent large outbreak of gastroenteritis. With a few exceptions, the majority of the genes identified as required for maintenance and transmission of pESBL matched those of their previously defined R64 counterparts. However, our analyses of the high-density transposon insertion library in pESBL also revealed two very short and linked regions that constitute a previously unrecognized regulatory system controlling spread of IncI1 plasmids. In addition, we investigated the function of the pESBL-encoded M.EcoGIX methyltransferase, which is also encoded by many other IncI1 and IncF plasmids. This enzyme proved to protect pESBL from restriction in new hosts, suggesting it aids in expanding the plasmid's host range. Collectively, our work illustrates the power of the TnSeq approach to enable rapid and comprehensive analyses of plasmid genes and sequences that facilitate the dissemination of determinants of antibiotic resistance.
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Affiliation(s)
- Yoshiharu Yamaichi
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris-Sud, Gif-sur-Yvette 91198, France
| | - Michael C. Chao
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jumpei Sasabe
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
- Department of Anatomy, Keio University School of Medicine, Shinjuku-ku, Tokyo160-8582, Japan
| | - Lars Clark
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Brigid M. Davis
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Nozomi Yamamoto
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan
| | - Hiroshi Mori
- Department of Biological Information, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan
| | - Ken Kurokawa
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan
- Department of Biological Information, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan
| | - Matthew K. Waldor
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Boston, MA 02115, USA
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9
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Li S, Zhao H, Li Y, Niu S, Cai B. Complete nucleotide sequence of plasmid pND6-2 from Pseudomonas putida ND6 and characterization of conjugative genes. Gene 2013; 512:148-56. [DOI: 10.1016/j.gene.2012.09.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/22/2012] [Accepted: 09/12/2012] [Indexed: 11/27/2022]
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10
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Sakuma T, Tazumi S, Furuya N, Komano T. ExcA proteins of IncI1 plasmid R64 and IncIγ plasmid R621a recognize different segments of their cognate TraY proteins in entry exclusion. Plasmid 2012. [PMID: 23201046 DOI: 10.1016/j.plasmid.2012.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Entry exclusion is a process whereby plasmid transfer between donor and recipient cells harboring identical or closely related conjugative plasmids is inhibited. Exclusion proteins in the recipient cells are responsible for entry exclusion. Although IncI1 Plasmid R64 and IncIγ plasmid R621a exhibit similar genome structure in replication, transfer, and leading regions, they belong to different incompatibility and exclusion groups. The amino acid sequences of TraY and ExcA proteins are significantly different between R64 and R621a. In the present study, TraY proteins of R64 and R621a were exchanged. Transfer of R64 derivative carrying R621a TraY was inhibited by recipient R621a ExcA but not R64 ExcA and transfer of R621a derivative carrying R64 TraY was inhibited by recipient R64 ExcA but not R621a ExcA. This indicates that R64 and R621a TraY proteins in the donor cells are the targets of cognate ExcA proteins in the recipient proteins. Since two segments, an internal and a C-terminal segment, were found to vary between R64 and R621a TraY proteins, various chimera TraY proteins were constructed. Conjugation experiments suggested that the R64 internal variable segment recognizes R64 ExcA protein and the R621a C-terminal variable segment recognizes R621a ExcA protein.
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Affiliation(s)
- Takahiro Sakuma
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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11
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Madsen JS, Burmølle M, Hansen LH, Sørensen SJ. The interconnection between biofilm formation and horizontal gene transfer. ACTA ACUST UNITED AC 2012; 65:183-95. [PMID: 22444301 DOI: 10.1111/j.1574-695x.2012.00960.x] [Citation(s) in RCA: 364] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 03/08/2012] [Accepted: 03/08/2012] [Indexed: 12/24/2022]
Abstract
Recent research has revealed that horizontal gene transfer and biofilm formation are connected processes. Although published research investigating this interconnectedness is still limited, we will review this subject in order to highlight the potential of these observations because of their believed importance in the understanding of the adaptation and subsequent evolution of social traits in bacteria. Here, we discuss current evidence for such interconnectedness centred on plasmids. Horizontal transfer rates are typically higher in biofilm communities compared with those in planktonic states. Biofilms, furthermore, promote plasmid stability and may enhance the host range of mobile genetic elements that are transferred horizontally. Plasmids, on the other hand, are very well suited to promote the evolution of social traits such as biofilm formation. This, essentially, transpires because plasmids are independent replicons that enhance their own success by promoting inter-bacterial interactions. They typically also carry genes that heighten their hosts' direct fitness. Furthermore, current research shows that the so-called mafia traits encoded on mobile genetic elements can enforce bacteria to maintain stable social interactions. It also indicates that horizontal gene transfer ultimately enhances the relatedness of bacteria carrying the mobile genetic elements of the same origin. The perspective of this review extends to an overall interconnectedness between horizontal gene transfer, mobile genetic elements and social evolution of bacteria.
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12
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Complete DNA sequence analysis of enterohemorrhagic Escherichia coli plasmid pO157_2 in β-glucuronidase-positive E. coli O157:H7 reveals a novel evolutionary path. J Bacteriol 2012; 194:3457-63. [PMID: 22522897 DOI: 10.1128/jb.00197-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Strains of enterohemorragic Escherichia coli (EHEC) O157:H7 that are non-sorbitol fermenting (NSF) and β-glucuronidase negative (GUD(-)) carry a large virulence plasmid, pO157 (>90,000 bp), whereas closely related sorbitol-fermenting (SF) E. coli O157:H(-) strains carry plasmid pSFO157 (>120,000 bp). GUD(+) NSF O157:H7 strains are presumed to be precursors of GUD(-) NSF O157:H7 strains that also carry pO157. In this study, we report the complete sequence of a novel virulence plasmid, pO157-2 (89,762 bp), isolated from GUD(+) NSF O157:H7 strain G5101. PCR analysis confirmed the presence of pO157-2 in six other strains of GUD(+) NSF O157:H7. pO157-2 carries genes associated with virulence (e.g., hemolysin genes) and conjugation (tra and trb genes) but lacks katP and espP present in pO157. Comparative analysis of the three EHEC plasmids shows that pO157-2 is highly related to pO157 and pSFO157 but not ancestral to pO157. These results indicated that GUD(+) NSF O157:H7 strains might not be direct precursors to GUD(-) NSF O157:H7 as previously proposed but rather have evolved independently from a common ancestor.
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13
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Archer CT, Kim JF, Jeong H, Park JH, Vickers CE, Lee SY, Nielsen LK. The genome sequence of E. coli W (ATCC 9637): comparative genome analysis and an improved genome-scale reconstruction of E. coli. BMC Genomics 2011; 12:9. [PMID: 21208457 PMCID: PMC3032704 DOI: 10.1186/1471-2164-12-9] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 01/06/2011] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Escherichia coli is a model prokaryote, an important pathogen, and a key organism for industrial biotechnology. E. coli W (ATCC 9637), one of four strains designated as safe for laboratory purposes, has not been sequenced. E. coli W is a fast-growing strain and is the only safe strain that can utilize sucrose as a carbon source. Lifecycle analysis has demonstrated that sucrose from sugarcane is a preferred carbon source for industrial bioprocesses. RESULTS We have sequenced and annotated the genome of E. coli W. The chromosome is 4,900,968 bp and encodes 4,764 ORFs. Two plasmids, pRK1 (102,536 bp) and pRK2 (5,360 bp), are also present. W has unique features relative to other sequenced laboratory strains (K-12, B and Crooks): it has a larger genome and belongs to phylogroup B1 rather than A. W also grows on a much broader range of carbon sources than does K-12. A genome-scale reconstruction was developed and validated in order to interrogate metabolic properties. CONCLUSIONS The genome of W is more similar to commensal and pathogenic B1 strains than phylogroup A strains, and therefore has greater utility for comparative analyses with these strains. W should therefore be the strain of choice, or 'type strain' for group B1 comparative analyses. The genome annotation and tools created here are expected to allow further utilization and development of E. coli W as an industrial organism for sucrose-based bioprocesses. Refinements in our E. coli metabolic reconstruction allow it to more accurately define E. coli metabolism relative to previous models.
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Affiliation(s)
- Colin T Archer
- Australian Institute for Bioengineering and Nanotechnology, Cnr Cooper and College Rds, The University of Queensland, St Lucia, Queensland 4072 Australia
| | - Jihyun F Kim
- Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon, Korea
| | - Haeyoung Jeong
- Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon, Korea
| | - Jin Hwan Park
- Department of Chemical and Biomolecular Engineering (BK21 program) and Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Claudia E Vickers
- Australian Institute for Bioengineering and Nanotechnology, Cnr Cooper and College Rds, The University of Queensland, St Lucia, Queensland 4072 Australia
| | - Sang Yup Lee
- Department of Chemical and Biomolecular Engineering (BK21 program) and Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Lars K Nielsen
- Australian Institute for Bioengineering and Nanotechnology, Cnr Cooper and College Rds, The University of Queensland, St Lucia, Queensland 4072 Australia
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14
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Hurst MRH, Becher SA, O'Callaghan M. Nucleotide sequence of the Serratia entomophila plasmid pADAP and the Serratia proteamaculans pU143 plasmid virulence associated region. Plasmid 2010; 65:32-41. [PMID: 20950642 DOI: 10.1016/j.plasmid.2010.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 10/05/2010] [Accepted: 10/06/2010] [Indexed: 10/19/2022]
Abstract
Some strains of Serratia entomophila and S. proteamaculans cause amber disease of the New Zealand grass grub Costelytra zealandica (Coleoptera: Scarabaeidae), an important pasture pest in New Zealand. The disease determinants of S. entomophila, are encoded on a 153,404-bp plasmid, termed pADAP for amber disease associated plasmid. The S. proteamaculans strain 143 (Sp143) exhibits an unusual pathotype, where only 60-70% of C. zealandica larvae infected with the bacterium succumb to disease. DNA sequence analysis of the Sp143 pU143 virulence associated region identified high DNA similarity to the pADAP sep virulence associated region, with DNA sequence variation in the sepA gene and the variable region of the sepC component. No pADAP anti-feeding prophage orthologue was detected in the Sp143 genome. The region of pADAP replication was cloned and found to replicate in S. entomophila but not in Escherichia coli. DNA sequence analysis of the plasmid pSG348 repA gene from the French isolate of Serratia grimesii, identified 93% DNA identity to the pADAP repA gene. A comparison of the pU143 virulence associated region with the completed pADAP nucleotide sequence is given.
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Affiliation(s)
- Mark R H Hurst
- Biocontrol and Biosecurity, AgResearch, Lincoln Research Centre, Private Bag 4749, Christchurch 8140, New Zealand.
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15
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Complete genome sequence of the incompatibility group I1 plasmid R64. Plasmid 2010; 64:92-103. [DOI: 10.1016/j.plasmid.2010.05.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 05/24/2010] [Accepted: 05/26/2010] [Indexed: 11/20/2022]
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16
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Venturini C, Beatson SA, Djordjevic SP, Walker MJ. Multiple antibiotic resistance gene recruitment onto the enterohemorrhagic
Escherichia coli
virulence plasmid. FASEB J 2009; 24:1160-6. [PMID: 19917674 DOI: 10.1096/fj.09-144972] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Carola Venturini
- School of Biological SciencesUniversity of WollongongWollongong New South Wales Australia
| | - Scott A. Beatson
- School of Chemistry and Molecular BioscienceUniversity of QueenslandBrisbane Queensland Australia
| | - Steven P. Djordjevic
- NSW Department of Primary IndustriesMenangle New South Wales Australia
- Institute for the Biotechnology of Infectious DiseasesUniversity of Technology SydneySydney New South Wales Australia
| | - Mark J. Walker
- School of Biological SciencesUniversity of WollongongWollongong New South Wales Australia
- School of Chemistry and Molecular BioscienceUniversity of QueenslandBrisbane Queensland Australia
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17
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Golubov A, Neubauer H, Nölting C, Heesemann J, Rakin A. Structural organization of the pFra virulence-associated plasmid of rhamnose-positive Yersinia pestis. Infect Immun 2004; 72:5613-21. [PMID: 15385458 PMCID: PMC517582 DOI: 10.1128/iai.72.10.5613-5621.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 137,036-bp plasmid pG8786 from rhamnose-positive Yersinia pestis G8786 isolated from the high mountainous Caucasian plague focus in Georgia is an enlarged form of the pFra virulence-associated plasmid containing genes for synthesis of the antigen fraction 1 and phospholipase D. In addition to the completely conserved genes of the pFra backbone, pG8786 contains two large regions consisting of 4,642 and 32,617 bp, designated regions 1 and 2, respectively. Region 1 retains a larger part of Salmonella enterica serovar Typhi plasmid pHCM2 resembling the backbone of pFra replicons, while region 2 contains 25 open reading frames with high levels of similarity to the transfer genes of the F-like plasmids. Surprisingly, region 1 is also present in the pFra plasmid of avirulent Y. pestis strain 91001 isolated in Inner Mongolia, People's Republic of China. Despite the fact that some genes typically involved in conjugative transfer of the F-like replicons are missing in pG8786, we cannot exclude the possibility that pG8786 might be transmissive under certain conditions. pG8786 seems to be an ancient form of the pFra group of plasmids that were conserved due to the strict geographical isolation of rhamnose-positive Y. pestis strains in the high mountainous Caucasian plague locus.
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Affiliation(s)
- Andrey Golubov
- Max von Pettenkofer Institute for Hygiene and Medical Microbiology, Munich, Germany
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18
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Leyton DL, Sloan J, Hill RE, Doughty S, Hartland EL. Transfer region of pO113 from enterohemorrhagic Escherichia coli: similarity with R64 and identification of a novel plasmid-encoded autotransporter, EpeA. Infect Immun 2003; 71:6307-19. [PMID: 14573650 PMCID: PMC219559 DOI: 10.1128/iai.71.11.6307-6319.2003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2003] [Revised: 05/20/2003] [Accepted: 07/15/2003] [Indexed: 11/20/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a prominent, food-borne cause of diarrhea, bloody diarrhea, and the hemolytic uremic syndrome in industrialized countries. Most strains of EHEC carry the locus for enterocyte effacement (LEE) pathogenicity island, but a proportion of isolates from patients with severe disease do not carry LEE and very little is known about virulence factors in these organisms. LEE-negative strains of EHEC typically express Shiga toxin 2 and carry a large plasmid that encodes the production of EHEC hemolysin. In this study, we determined the nucleotide sequence of the transfer region of pO113, the large hemolysin plasmid from LEE-negative EHEC O113:H21 (EH41). This 63.9-kb region showed a high degree of similarity with the transfer region of R64, and pO113 was capable of self-transmission at low frequencies. Unlike R64 and the related dot/icm system of Legionella pneumophila, however, pO113 was unable to mobilize RSF1010. In addition, the pO113 transfer region encoded a novel high-molecular-weight serine protease autotransporter of Enterobacteriaceae (SPATE) protein, termed EpeA. Like other SPATEs, EpeA exhibited protease activity and mucinase activity, but expression was not associated with a cytopathic effect on epithelial cells. Analysis of a second high-molecular-weight secreted protein revealed that pO113 also encodes EspP, a cytopathic SPATE identified previously in EHEC O157:H7. The nucleotide sequences encoding the predicted beta-domains of espP and epeA were identical and also shared significant homology with a third SPATE protein, EspI. Both espP and epeA were detected in several LEE-negative clinical isolates of EHEC and thus may contribute to the pathogenesis of this subset of EHEC.
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Affiliation(s)
- Denisse L Leyton
- Department of Microbiology, School of Biomedical Sciences, Monash University, Clayton 3800, Victoria, Australia
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19
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Furuya N, Komano T. NikAB- or NikB-dependent intracellular recombination between tandemly repeated oriT sequences of plasmid R64 in plasmid or single-stranded phage vectors. J Bacteriol 2003; 185:3871-7. [PMID: 12813081 PMCID: PMC161590 DOI: 10.1128/jb.185.13.3871-3877.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The origin of transfer (oriT) of a bacterial plasmid plays a key role in both the initiation and termination of conjugative DNA transfer. We have previously shown that a conjugation-dependent recombination between the tandem R64 oriT sequences cloned into pHSG398 occurred, resulting in the deletion of the intervening sequence during DNA transfer. In this study, we tandemly cloned two oriT sequences of IncI1 plasmid R64 into pUC18. Specific recombination between the two oriT sequences in pUC18 was observed within Escherichia coli cells harboring mini-R64. This recombination was found to be independent of both the recA gene and conjugative DNA transfer. The R64 genes nikA and nikB, required for conjugal DNA processing, were essential for this recombination. Although a fully active 92-bp oriT sequence was required at one site for the recombination, the 44-bp oriT core sequence was sufficient at the other site. Furthermore, when two oriT sequences were tandemly cloned into the single-stranded phage vector M13 and propagated within E. coli cells, recombination between the two oriT sequences was observed, depending on the nikB gene. These results suggest that the R64 relaxase protein NikB can execute cleavage and rejoining of single-stranded oriT DNA within E. coli cells, whereas such a reaction in double-stranded oriT DNA requires collaboration of the two relaxosome proteins, NikA and NikB.
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Affiliation(s)
- Nobuhisa Furuya
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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20
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Furuya N, Komano T. Initiation and termination of DNA transfer during conjugation of IncI1 plasmid R64: roles of two sets of inverted repeat sequences within oriT in termination of R64 transfer. J Bacteriol 2000; 182:3191-6. [PMID: 10809699 PMCID: PMC94506 DOI: 10.1128/jb.182.11.3191-3196.2000] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intercellular transfer of plasmid DNA during bacterial conjugation initiates and terminates at a specific origin of transfer, oriT. We have investigated the oriT structure of conjugative plasmid R64 with regard to the initiation and termination of DNA transfer. Using recombinant plasmids containing two tandemly repeated R64 oriT sequences with or without mutations, the subregions required for initiation and termination were determined by examining conjugation-mediated deletion between the repeated oriTs. The oriT subregion required for initiation was found to be identical to the 44-bp oriT core sequence consisting of two units, the conserved nick region sequence and the 17-bp repeat A sequence, that are recognized by R64 relaxosome proteins NikB and NikA, respectively. In contrast, the nick region sequence and two sets of inverted repeat sequences within the 92-bp minimal oriT sequence were required for efficient termination. Mutant repeat A sequences lacking NikA-binding ability were found to be sufficient for termination, suggesting that the inverted repeat structures are involved in the termination process. A duplication of the DNA segment between the repeated oriTs was also found after mobilization of the plasmid carrying initiation-deficient but termination-proficient oriT and initiation-proficient but termination-deficient oriT, suggesting that the 3' terminus of the transferred strand is elongated by rolling-circle-DNA synthesis.
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Affiliation(s)
- N Furuya
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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21
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Abstract
Conservative site-specific recombination functions to create biological diversity in prokaryotes. Simple site-specific recombination systems consist of two recombination sites and a recombinase gene. The plasmid R64 shufflon contains seven recombination sites, which flank and separate four DNA segments. Site-specific recombinations mediated by the product of the rci gene between any two inverted recombination sites result in the inversion of four DNA segments independently or in groups. The shufflon functions as a biological switch to select one of seven C-terminal segments of the PilV proteins, which is a minor component of R64 thin pilus. The shufflon determines the recipient specificity in liquid matings of plasmid R64. Other multiple inversion systems as well as integrons, which are multiple insertion systems, are also described in this review.
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Affiliation(s)
- T Komano
- Department of Biology, Tokyo Metropolitan University, Japan.
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22
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Komano T, Yoshida T, Narahara K, Furuya N. The transfer region of IncI1 plasmid R64: similarities between R64 tra and legionella icm/dot genes. Mol Microbiol 2000; 35:1348-59. [PMID: 10760136 DOI: 10.1046/j.1365-2958.2000.01769.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The entire nucleotide sequence of the transfer region of IncI1 plasmid R64 was determined together with previously reported sequences. Twenty-two transfer genes, traE-Y and nuc, were newly identified in the present study. The protein products of 17 genes were detected by maxicell experiments or by the T7 RNA polymerase expression system. Mutagenesis experiments indicated that 16 genes were indispensable for R64 transfer both in liquid and on surfaces. In summary, the R64 transfer region located within an approximately 54 kb DNA segment was shown to encode the most complex transfer system so far studied. It contains at least 49 genes and may produce 58 different proteins as a result of shufflon DNA rearrangement and overlapping genes. Among the 49 genes, 23 tra, trb and nik genes have been shown to be indispensable for R64 conjugal transfer in liquid and on surfaces. Twelve additional pil genes are required only for liquid matings. The amino acid sequences of 10 R64 tra/trb products share similarity with those of the icm/dot products of Legionella pneumophila that are responsible for its virulence, suggesting that the R64 transfer and L. pneumophila icm/dot systems have evolved from a common ancestral genetic system.
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Affiliation(s)
- T Komano
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji-shi, Tokyo 192-0397, Japan.
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23
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Sakai D, Komano T. The pilL and pilN genes of IncI1 plasmids R64 and ColIb-P9 encode outer membrane lipoproteins responsible for thin pilus biogenesis. Plasmid 2000; 43:149-52. [PMID: 10686134 DOI: 10.1006/plas.1999.1434] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The predicted amino acid sequences of the pilL and pilN genes, required for the thin pilus formation of IncI1 plasmids R64 and ColIb-P9, contain N-terminal lipoprotein signal peptide motifs. The pilL and pilN products were labeled with [(3)H]palmitic acid as 38- and 57-kDa proteins, respectively, indicating that they are lipoproteins. Both PilL and PilN were localized to the outer membrane.
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Affiliation(s)
- D Sakai
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo, 192-0397, Japan
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24
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Forti F, Polo S, Lane KB, Six EW, Sironi G, Dehò G, Ghisotti D. Translation of two nested genes in bacteriophage P4 controls immunity-specific transcription termination. J Bacteriol 1999; 181:5225-33. [PMID: 10464191 PMCID: PMC94026 DOI: 10.1128/jb.181.17.5225-5233.1999] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In phage P4, transcription of the left operon may occur from both the constitutive PLE promoter and the regulated PLL promoter, about 400 nucleotides upstream of PLE. A strong Rho-dependent termination site, timm, is located downstream of both promoters. When P4 immunity is expressed, transcription starting at PLE is efficiently terminated at timm, whereas transcription from PLL is immunity insensitive and reads through timm. We report the identification of two nested genes, kil and eta, located in the P4 left operon. The P4 kil gene, which encodes a 65-amino-acid polypeptide, is the first translated gene downstream of the PLE promoter, and its expression is controlled by P4 immunity. Overexpression of kil causes cell killing. This gene is the terminal part of a longer open reading frame, eta, which begins upstream of PLE. The eta gene is expressed when transcription starts from the PLL promoter. Three likely start codons predict a size between 197 and 199 amino acids for the Eta gene product. Both kil and eta overlap the timm site. By cloning kil upstream of a tRNA reporter gene, we demonstrated that translation of the kil region prevents premature transcription termination at timm. This suggests that P4 immunity might negatively control kil translation, thus enabling transcription termination at timm. Transcription starting from PL proceeds through timm. Mutations that create nonsense codons in eta caused premature termination of transcription starting from PLL. Suppression of the nonsense mutation restored transcription readthrough at timm. Thus, termination of transcription from PLL is prevented by translation of eta.
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Affiliation(s)
- F Forti
- Dipartimento di Genetica e di Biologia dei Microrganismi, Università di Milano, Milan, Italy
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25
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Masuda S, Matsumoto Y, Nagashima KV, Shimada K, Inoue K, Bauer CE, Matsuura K. Structural and functional analyses of photosynthetic regulatory genes regA and regB from Rhodovulum sulfidophilum, Roseobacter denitrificans, and Rhodobacter capsulatus. J Bacteriol 1999; 181:4205-15. [PMID: 10400577 PMCID: PMC93921 DOI: 10.1128/jb.181.14.4205-4215.1999] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genes coding for putative RegA, RegB, and SenC homologues were identified and characterized in the purple nonsulfur photosynthetic bacteria Rhodovulum sulfidophilum and Roseobacter denitrificans, species that demonstrate weak or no oxygen repression of photosystem synthesis. This additional sequence information was then used to perform a comparative analysis with previously sequenced RegA, RegB, and SenC homologues obtained from Rhodobacter capsulatus and Rhodobacter sphaeroides. These are photosynthetic bacteria that exhibit a high level of oxygen repression of photosystem synthesis controlled by the RegA-RegB two-component regulatory system. The response regulator, RegA, exhibits a remarkable 78.7 to 84.2% overall sequence identity, with total conservation within a putative helix-turn-helix DNA-binding motif. The RegB sensor kinase homologues also exhibit a high level of sequence conservation (55.9 to 61.5%) although these additional species give significantly different responses to oxygen. A Rhodovulum sulfidophilum mutant lacking regA or regB was constructed. These mutants produced smaller amounts of photopigments under aerobic and anaerobic conditions, indicating that the RegA-RegB regulon controls photosynthetic gene expression in this bacterium as it does as in Rhodobacter species. Rhodobacter capsulatus regA- or regB-deficient mutants recovered the synthesis of a photosynthetic apparatus that still retained regulation by oxygen tension when complemented with reg genes from Rhodovulum sulfidophilum and Roseobacter denitrificans. These results suggest that differential expression of photosynthetic genes in response to aerobic and anaerobic growth conditions is not the result of altered redox sensing by the sensor kinase protein, RegB.
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Affiliation(s)
- S Masuda
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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26
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Abstract
The IncI1 plasmid R64 produces two kinds of sex pili: a thin pilus and a thick pilus. The thin pilus, which belongs to the type IV family, is required only for liquid matings. Fourteen genes, pilI to -V, were found in the DNA region responsible for the biogenesis of the R64 thin pilus (S.-R. Kim and T. Komano, J. Bacteriol. 179:3594-3603, 1997). In this study, we introduced frameshift mutations into each of the 14 pil genes to test their requirement for R64 thin pilus biogenesis. From the analyses of extracellular secretion of thin pili and transfer frequency in liquid matings, we found that 12 genes, pilK to -V, are required for the formation of the thin pilus. Complementation experiments excluded the possible polar effects of each mutation on the expression of downstream genes. Two genes, traBC, were previously shown to be required for the expression of the pil genes. In addition, the rci gene is responsible for modulating the structure and function of the R64 thin pilus via the DNA rearrangement of the shufflon. Altogether, 15 genes, traBC, pilK through pilV, and rci, are essential for R64 thin pilus formation and function.
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Affiliation(s)
- T Yoshida
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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27
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Horiuchi T, Komano T. Mutational analysis of plasmid R64 thin pilus prepilin: the entire prepilin sequence is required for processing by type IV prepilin peptidase. J Bacteriol 1998; 180:4613-20. [PMID: 9721303 PMCID: PMC107475 DOI: 10.1128/jb.180.17.4613-4620.1998] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The thin pili of IncI1 plasmid R64, which is required for conjugation in liquid media, belong to the type IV pilus family. They consist of a major subunit, the pilS product, and a minor component, one of the seven pilV products. The pilS product is first synthesized as a 22-kDa prepilin, processed to a 19-kDa mature pilin by the function of the pilU product, and then secreted outside the cell. The mature pilin is assembled to form a thin pilus with the pilV product. To reveal the relationship between the structure and function of the pilS product, 27 missense mutations, three N-terminal deletions, and two C-terminal deletions were constructed by PCR and site-directed mutagenesis. The characteristics of 32 mutant pilS products were analyzed. Four pilS mutant phenotype classes were identified. The products of 10 class I mutants were not processed by prepilin peptidase; the extracellular secretion of the products of two class II mutants was inhibited; from 11 class III mutants, thin pili with reduced activities in liquid mating were formed; from 9 class IV mutants, thin pili with mating activity similar to that of the wild-type pilS gene were formed. The point mutations of the class I mutants were distributed throughout the prepilin sequence, suggesting that processing of the pilS product requires the entire prepilin sequence.
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Affiliation(s)
- T Horiuchi
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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Yoshida T, Furuya N, Ishikura M, Isobe T, Haino-Fukushima K, Ogawa T, Komano T. Purification and characterization of thin pili of IncI1 plasmids ColIb-P9 and R64: formation of PilV-specific cell aggregates by type IV pili. J Bacteriol 1998; 180:2842-8. [PMID: 9603870 PMCID: PMC107247 DOI: 10.1128/jb.180.11.2842-2848.1998] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Thin pili of the closely related IncI1 plasmids ColIb-P9 and R64 are required only for liquid mating and belong to the type IV family of pili. They were sedimented by ultracentrifugation from culture medium in which Escherichia coli cells harboring ColIb-P9- or R64-derived plasmids had been grown, and then the pili were purified by CsCl density gradient centrifugation. In negatively stained thin pilus samples, long rods with a diameter of 6 nm, characteristic of type IV pili, were observed under an electron microscope. Gel electrophoretic analysis of purified ColIb-P9 thin pili indicated that thin pili consist of two kinds of proteins, pilin and the PilV protein. Pilin was demonstrated to be the product of the pilS gene. Pilin was first synthesized as a 22-kDa prepilin from the pilS gene and subsequently processed to a 19-kDa protein by the function of the pilU product. The N-terminal amino group of the processed protein was shown to be modified. The C-terminal segments of the pilV products vary among six or seven different types, as a result of shufflon DNA rearrangements of the pilV gene. These PilV proteins were revealed to comprise a minor component of thin pili. Formation of PilV-specific cell aggregates by ColIb-P9 and R64 thin pili was demonstrated and may play an important role in liquid mating.
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Affiliation(s)
- T Yoshida
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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Zatyka M, Thomas CM. Control of genes for conjugative transfer of plasmids and other mobile elements. FEMS Microbiol Rev 1998; 21:291-319. [PMID: 25508777 DOI: 10.1111/j.1574-6976.1998.tb00355.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Conjugative transfer is a primary means of spread of mobile genetic elements (plasmids and transposons) between bacteria.It leads to the dissemination and evolution of the genes (such as those conferring resistance to antibiotics) which are carried by the plasmid. Expression of the plasmid genes needed for conjugative transfer is tightly regulated so as to minimise the burden on the host. For plasmids such as those belonging to the IncP group this results in downregulation of the transfer genes once all bacteria have a functional conjugative apparatus. For F-like plasmids (apart from F itself which is a derepressed mutant) tight control results in very few bacteria having a conjugative apparatus. Chance encounters between the rare transfer-proficient bacteria and a potential recipient initiate a cascade of transfer which can continue until all potential recipients have acquired the plasmid. Other systems express their transfer genes in response to specific stimuli. For the pheromone-responsive plasmids of Enterococcus it is small peptide signals from potential recipients which trigger the conjugative transfer genes. For the Ti plasmids of Agrobacterium it is the presence of wounded plants which are susceptible to infection which stimulates T-DNA transfer to plants. Transfer and integration of T-DNA induces production of opines which the plasmid-positive bacteria can utilise. They multiply and when they reach an appropriate density their plasmid transfer system is switched on to allow transfer of the Ti plasmid to other bacteria. Finally some conjugative transfer systems are induced by the antibiotics to which the elements confer resistance. Understanding these control circuits may help to modify management of microbial communities where plasmid transfer is either desirable or undesirable. z 1998 Published by Elsevier Science B.V.
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Affiliation(s)
- M Zatyka
- School of Biological Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Abstract
The entire nucleotide sequence of the pil region of the IncI1 plasmid R64 was determined. Analysis of the sequence indicated that 14 genes, designated pilI through pilV, are involved in the formation of the R64 thin pilus. Protein products of eight pil genes were identified by the maxicell procedure. The pilN product was shown to be a lipoprotein by an experiment using globomycin. A computer search revealed that several R64 pil genes have amino acid sequence homology with proteins involved in type IV pilus biogenesis, protein secretion, and transformation competence. The pilS and pilV products were suggested to be prepilins for the R64 thin pilus, and the pilU product appears to be a prepilin peptidase. These results suggest that the R64 thin pilus belongs to the type IV family, specifically group IVB, of pili. The requirement of the pilR and pilU genes for R64 liquid mating was demonstrated by constructing their frameshift mutations. Comparison of three type IVB pilus biogenesis systems, the pil system of R64, the toxin-coregulated pilus (tcp) system of Vibrio cholerae, and the bundle-forming pilus (bfp) system of enteropathogenic Escherichia coli, suggests that they have evolved from a common ancestral gene system.
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Affiliation(s)
- S R Kim
- Department of Biology, Tokyo Metropolitan University, Hachioji, Japan
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Narahara K, Rahman E, Furuya N, Komano T. Requirement of a limited segment of the sog gene for plasmid R64 conjugation. Plasmid 1997; 38:1-11. [PMID: 9281491 DOI: 10.1006/plas.1997.1297] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The sog gene of the IncI1 plasmid R64 was sequenced and characterized. The sog gene was shown to express two acidic proteins, SogL and SogS, with 1255 and 844 amino acid residues, respectively. The SogS protein was expressed by translational reinitiation within the SogL reading frame. Analysis of dnaG-suppression activity using the Escherichia coli dnaG strain indicated that the domain for this activity was located within the N-terminal one-third segment of the SogL protein. A Deltasog mutation was constructed by replacing most of the sog coding sequence with a DNA fragment encoding a tetracycline resistance gene. Introduction of the Deltasog mutation into an R64 derivative resulted in approximately a 50-fold reduction in transfer frequency. It was observed that only a limited portion of the SogL or SogS protein corresponding to an internal 0.94-kb EcoRV-SnaBI segment of the sog gene was required for the conjugal transfer of R64.
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Affiliation(s)
- K Narahara
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Tokyo, 192-03, Japan
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Furuya N, Komano T. Nucleotide sequence and characterization of the trbABC region of the IncI1 Plasmid R64: existence of the pnd gene for plasmid maintenance within the transfer region. J Bacteriol 1996; 178:1491-7. [PMID: 8626273 PMCID: PMC177830 DOI: 10.1128/jb.178.6.1491-1497.1996] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A 6.72-kb DNA sequence between the exc gene and the oriT operon within the transfer region of IncI1 plasmid R64 was sequenced and characterized. Three novel transfer genes, trbA, trbB, and trbC, were found in this region, along with the pnd gene responsible for plasmid maintenance. The trbABC genes appear to be organized into an operon located adjacent to the oriT operon in the opposite orientation. The trbA and trbC genes were shown to be indispensable for R64 plasmid transfer, while residual transfer activity was detected in the case of R64 derivatives carrying the trbB++ deletion mutation. The T7 RNA polymerase-promoter system revealed that the trbB gene produced a 43-kDa protein and the trbC gene produced an 85-kDa protein. The nucleotide sequence of the pnd gene is nearly identical to that of plasmid R483, indicating a function in plasmid maintenance. The plasmid stability test indicated that the mini-R64 derivatives with the pnd gene are more stably maintained in Escherichia coli cells under nonselective conditions than the mini-R64 derivatives without the pnd gene. It was also shown that the R64 transfer system itself is involved in plasmid stability to a certain degree. Deletion of the pnd gene from the tra+ mini-R64 derivative did not affect transfer frequency. DNA segments between the exc and trbA genes for IncI1 plasmids R64, Colb-P9, and R144 were compared in terms of their physical and genetic organization.
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Affiliation(s)
- N Furuya
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Japan
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Komano T, Kim SR, Yoshida T. Mating variation by DNA inversions of shufflon in plasmid R64. ADVANCES IN BIOPHYSICS 1995; 31:181-93. [PMID: 7625273 DOI: 10.1016/0065-227x(95)99391-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Gene organization of the 54-kb transfer region of IncI1 plasmid R64 was deduced from the DNA sequence. Forty-eight ORFs were found in this region. A unique DNA rearrangement designated shufflon is located at the downstream region of an operon responsible for synthesis of thin pilus. The shufflon of R64 consists of four DNA segments, designated as A, B, C, and D, which are flanked and separated by seven 19-bp repeat sequences. Site-specific recombination mediated by the product of the rci gene between any two inverted repeats results in a complex DNA rearrangement. An analysis of open reading frames revealed that the shufflon is a biological switch to select one of seven C-terminal segments of the pilV genes. The products of pilV genes were shown to be components of thin pilus which was required for liquid mating. Seven R64 derivatives where the pilV genes were fixed in the seven C-terminal segments were constructed and their transfer frequencies in liquid mating were measured using various bacterial strains as recipients. Transfer frequencies of R64 in liquid mating strongly depended on the combination of C-terminal segments of the pilV genes in donor cells and bacterial strains of recipient cells, suggesting that the shufflon determines the recipient specificity in liquid mating of plasmid R64.
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Affiliation(s)
- T Komano
- Department of Biology, Tokyo Metropolitan University, Japan
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