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Skutel M, Yanovskaya D, Demkina A, Shenfeld A, Musharova O, Severinov K, Isaev A. RecA-dependent or independent recombination of plasmid DNA generates a conflict with the host EcoKI immunity by launching restriction alleviation. Nucleic Acids Res 2024; 52:5195-5208. [PMID: 38567730 PMCID: PMC11109961 DOI: 10.1093/nar/gkae243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 03/17/2024] [Accepted: 03/22/2024] [Indexed: 05/23/2024] Open
Abstract
Bacterial defence systems are tightly regulated to avoid autoimmunity. In Type I restriction-modification (R-M) systems, a specific mechanism called restriction alleviation (RA) controls the activity of the restriction module. In the case of the Escherichia coli Type I R-M system EcoKI, RA proceeds through ClpXP-mediated proteolysis of restriction complexes bound to non-methylated sites that appear after replication or reparation of host DNA. Here, we show that RA is also induced in the presence of plasmids carrying EcoKI recognition sites, a phenomenon we refer to as plasmid-induced RA. Further, we show that the anti-restriction behavior of plasmid-borne non-conjugative transposons such as Tn5053, previously attributed to their ardD loci, is due to plasmid-induced RA. Plasmids carrying both EcoKI and Chi sites induce RA in RecA- and RecBCD-dependent manner. However, inactivation of both RecA and RecBCD restores RA, indicating that there exists an alternative, RecA-independent, homologous recombination pathway that is blocked in the presence of RecBCD. Indeed, plasmid-induced RA in a RecBCD-deficient background does not depend on the presence of Chi sites. We propose that processing of random dsDNA breaks in plasmid DNA via homologous recombination generates non-methylated EcoKI sites, which attract EcoKI restriction complexes channeling them for ClpXP-mediated proteolysis.
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Affiliation(s)
- Mikhail Skutel
- Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Daria Yanovskaya
- Skolkovo Institute of Science and Technology, Moscow, Russia
- Moscow Institute of Physics and Technology, Moscow, Russia
| | - Alina Demkina
- Skolkovo Institute of Science and Technology, Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | | | - Olga Musharova
- Skolkovo Institute of Science and Technology, Moscow, Russia
- Institute of Molecular Genetics, National Research Center Kurchatov Institute, Moscow, Russia
| | - Konstantin Severinov
- Waksman Institute of Microbiology, Piscataway, USA
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Artem Isaev
- Skolkovo Institute of Science and Technology, Moscow, Russia
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Graf F, Zehentner B, Fellner L, Scherer S, Neuhaus K. Three Novel Antisense Overlapping Genes in E. coli O157:H7 EDL933. Microbiol Spectr 2023; 11:e0235122. [PMID: 36533921 PMCID: PMC9927249 DOI: 10.1128/spectrum.02351-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 12/03/2022] [Indexed: 12/23/2022] Open
Abstract
The abundance of long overlapping genes in prokaryotic genomes is likely to be significantly underestimated. To date, only a few examples of such genes are fully established. Using RNA sequencing and ribosome profiling, we found expression of novel overlapping open reading frames in Escherichia coli O157:H7 EDL933 (EHEC). Indeed, the overlapping candidate genes are equipped with typical structural elements required for transcription and translation, i.e., promoters, transcription start sites, as well as terminators, all of which were experimentally verified. Translationally arrested mutants, unable to produce the overlapping encoded protein, were found to have a growth disadvantage when grown competitively against the wild type. Thus, the phenotypes found imply biological functionality of the genes at the level of proteins produced. The addition of 3 more examples of prokaryotic overlapping genes to the currently limited, yet constantly growing pool of such genes emphasizes the underestimated coding capacity of bacterial genomes. IMPORTANCE The abundance of long overlapping genes in prokaryotic genomes is likely to be significantly underestimated, since such genes are not allowed in genome annotations. However, ribosome profiling catches mRNA in the moment of being template for protein production. Using this technique and subsequent experiments, we verified 3 novel overlapping genes encoded in antisense of known genes. This adds more examples of prokaryotic overlapping genes to the currently limited, yet constantly growing pool of such genes.
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Affiliation(s)
- Franziska Graf
- Core Facility Microbiome, ZIEL – Institute for Food & Health, Technische Universität München, Freising, Germany
- Chair for Microbial Ecology, TUM School of Life Sciences, Technische Universität München, Freising, Germany
| | - Barbara Zehentner
- Chair for Microbial Ecology, TUM School of Life Sciences, Technische Universität München, Freising, Germany
| | - Lea Fellner
- Chair for Microbial Ecology, TUM School of Life Sciences, Technische Universität München, Freising, Germany
| | - Siegfried Scherer
- Core Facility Microbiome, ZIEL – Institute for Food & Health, Technische Universität München, Freising, Germany
- Chair for Microbial Ecology, TUM School of Life Sciences, Technische Universität München, Freising, Germany
| | - Klaus Neuhaus
- Core Facility Microbiome, ZIEL – Institute for Food & Health, Technische Universität München, Freising, Germany
- Chair for Microbial Ecology, TUM School of Life Sciences, Technische Universität München, Freising, Germany
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Tao S, Chen H, Li N, Wang T, Liang W. The Spread of Antibiotic Resistance Genes In Vivo Model. THE CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY = JOURNAL CANADIEN DES MALADIES INFECTIEUSES ET DE LA MICROBIOLOGIE MEDICALE 2022; 2022:3348695. [PMID: 35898691 PMCID: PMC9314185 DOI: 10.1155/2022/3348695] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/26/2022] [Accepted: 06/30/2022] [Indexed: 12/20/2022]
Abstract
Infections caused by antibiotic-resistant bacteria are a major public health threat. The emergence and spread of antibiotic resistance genes (ARGs) in the environment or clinical setting pose a serious threat to human and animal health worldwide. Horizontal gene transfer (HGT) of ARGs is one of the main reasons for the dissemination of antibiotic resistance in vitro and in vivo environments. There is a consensus on the role of mobile genetic elements (MGEs) in the spread of bacterial resistance. Most drug resistance genes are located on plasmids, and the spread of drug resistance genes among microorganisms through plasmid-mediated conjugation transfer is the most common and effective way for the spread of multidrug resistance. Experimental studies of the processes driving the spread of antibiotic resistance have focused on simple in vitro model systems, but the current in vitro protocols might not correctly reflect the HGT of antibiotic resistance genes in realistic conditions. This calls for better models of how resistance genes transfer and disseminate in vivo. The in vivo model can better mimic the situation that occurs in patients, helping study the situation in more detail. This is crucial to develop innovative strategies to curtail the spread of antibiotic resistance genes in the future. This review aims to give an overview of the mechanisms of the spread of antibiotic resistance genes and then demonstrate the spread of antibiotic resistance genes in the in vivo model. Finally, we discuss the challenges in controlling the spread of antibiotic resistance genes and their potential solutions.
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Affiliation(s)
- Shuan Tao
- School of Medical, Jiangsu University, Zhenjiang, Jiangsu Province, China
- Lianyungang Clinical College of Jiangsu University, Lianyungang, Jiangsu Province, China
| | - Huimin Chen
- School of Medical, Jiangsu University, Zhenjiang, Jiangsu Province, China
| | - Na Li
- Bengbu Medical College, Bengbu, Anhui Province, China
| | - Tong Wang
- Nanjing Brain Hospital Affiliated Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Wei Liang
- Lianyungang Clinical College of Jiangsu University, Lianyungang, Jiangsu Province, China
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Establishment Genes Present on pLS20 Family of Conjugative Plasmids Are Regulated in Two Different Ways. Microorganisms 2021; 9:microorganisms9122465. [PMID: 34946067 PMCID: PMC8708921 DOI: 10.3390/microorganisms9122465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022] Open
Abstract
During conjugation, a conjugative DNA element is transferred from a donor to a recipient cell via a connecting channel. Conjugation has clinical relevance because it is the major route for spreading antibiotic resistance and virulence genes. The conjugation process can be divided into different steps. The initial steps carried out in the donor cell culminate in the transfer of a single DNA strand (ssDNA) of the conjugative element into the recipient cell. However, stable settlement of the conjugative element in the new host requires at least two additional events: conversion of the transferred ssDNA into double-stranded DNA and inhibition of the hosts' defence mechanisms to prevent degradation of the transferred DNA. The genes involved in this late step are historically referred to as establishment genes. The defence mechanisms of the host must be inactivated rapidly and-importantly-transiently, because prolonged inactivation would make the cell vulnerable to the attack of other foreign DNA, such as those of phages. Therefore, expression of the establishment genes in the recipient cell has to be rapid but transient. Here, we studied regulation of the establishment genes present on the four clades of the pLS20 family of conjugative plasmids harboured by different Bacillus species. Evidence is presented that two fundamentally different mechanisms regulate the establishment genes present on these plasmids. Identification of the regulatory sequences were critical in revealing the establishment regulons. Remarkably, whereas the conjugation genes involved in the early steps of the conjugation process are conserved and are located in a single large operon, the establishment genes are highly variable and organised in multiple operons. We propose that the mosaical distribution of establishment genes in multiple operons is directly related to the variability of defence genes encoded by the host bacterial chromosomes.
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Watson AK, Lopez P, Bapteste E. Hundreds of out-of-frame remodelled gene families in the E. coli pangenome. Mol Biol Evol 2021; 39:6430988. [PMID: 34792602 PMCID: PMC8788219 DOI: 10.1093/molbev/msab329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
All genomes include gene families with very limited taxonomic distributions that potentially represent new genes and innovations in protein-coding sequence, raising questions on the origins of such genes. Some of these genes are hypothesized to have formed de novo, from noncoding sequences, and recent work has begun to elucidate the processes by which de novo gene formation can occur. A special case of de novo gene formation, overprinting, describes the origin of new genes from noncoding alternative reading frames of existing open reading frames (ORFs). We argue that additionally, out-of-frame gene fission/fusion events of alternative reading frames of ORFs and out-of-frame lateral gene transfers could contribute to the origin of new gene families. To demonstrate this, we developed an original pattern-search in sequence similarity networks, enhancing the use of these graphs, commonly used to detect in-frame remodeled genes. We applied this approach to gene families in 524 complete genomes of Escherichia coli. We identified 767 gene families whose evolutionary history likely included at least one out-of-frame remodeling event. These genes with out-of-frame components represent ∼2.5% of all genes in the E. coli pangenome, suggesting that alternative reading frames of existing ORFs can contribute to a significant proportion of de novo genes in bacteria.
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Affiliation(s)
- Andrew K Watson
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, 7, quai Saint Bernard, Paris, 75005, France
| | - Philippe Lopez
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, 7, quai Saint Bernard, Paris, 75005, France
| | - Eric Bapteste
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, 7, quai Saint Bernard, Paris, 75005, France
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6
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Zaworski J, Dagva O, Kingston AW, Fomenkov A, Morgan RD, Bossi L, Raleigh EA. Genome archaeology of two laboratory Salmonella enterica enterica sv Typhimurium. G3 (BETHESDA, MD.) 2021; 11:jkab226. [PMID: 34544129 PMCID: PMC8496262 DOI: 10.1093/g3journal/jkab226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/29/2021] [Indexed: 11/25/2022]
Abstract
The Salmonella research community has used strains and bacteriophages over decades, exchanging useful new isolates among laboratories for the study of cell surface antigens, metabolic pathways and restriction-modification (RM) studies. Here we present the sequences of two laboratory Salmonella strains (STK005, an isolate of LB5000; and its descendant ER3625). In the ancestry of LB5000, segments of ∼15 and ∼42 kb were introduced from Salmonella enterica sv Abony 803 into S. enterica sv Typhimurium LT2, forming strain SD14; this strain is thus a hybrid of S. enterica isolates. Strains in the SD14 lineage were used to define flagellar antigens from the 1950s to the 1970s, and to define three RM systems from the 1960s to the 1980s. LB5000 was also used as a host in phage typing systems used by epidemiologists. In the age of cheaper and easier sequencing, this resource will provide access to the sequence that underlies the extensive literature.
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Affiliation(s)
- Julie Zaworski
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | - Oyut Dagva
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | | | - Alexey Fomenkov
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | - Richard D Morgan
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | - Lionello Bossi
- CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), University Paris-Saclay, Gif-sur-Yvette 91198, France
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Zhao R, Feng J, Huang J, Li X, Li B. Reponses of microbial community and antibiotic resistance genes to the selection pressures of ampicillin, cephalexin and chloramphenicol in activated sludge reactors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142632. [PMID: 33045611 DOI: 10.1016/j.scitotenv.2020.142632] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/25/2020] [Accepted: 09/25/2020] [Indexed: 06/11/2023]
Abstract
High concentrations of antibiotics can exert strong selection pressures on the microbial community and promote the emergence and dissemination of antibiotic resistance genes (ARGs). The activated sludge reactors treating ampicillin, cephalexin and chloramphenicol production wastewater were established to investigate the responses of microbial community, ARGs and mobile genetic elements (MGEs) to antibiotics. Antibiotic selection pressures significantly declined the microbial diversity and changed microbial community structures. Based on metagenomic analysis, a total of 500 ARG subtypes affiliated with 18 ARG types were identified and 63 ARGs were shared by all samples. The substantial increase of ARG abundance and the shifts of ARG profiles were significantly correlated with antibiotic types and concentrations. The evident enrichment of non-corresponding ARG types suggested the strong co-selection effects of the target antibiotics. Additionally, metagenomic analysis revealed the occurrence of 104 MGEs belonging to various types and the five dominant MGEs were tnpA, intI1, tniA, tniB and IS91. The ARG-MGE co-occurrence associations implied the potential mobility of ARGs. Network analysis also demonstrated that five ARG types (aminoglycoside, beta-lactam, chloramphenicol, multidrug and tetracycline resistance genes) tended to co-occur internally and the obvious co-occurrence patterns among different ARG types indicated the potential for resistance co-selection. Moreover, 15 bacterial genera were speculated as the hosts of diverse ARGs. This study provides a comprehensive overview of the occurrence of ARGs and MGEs and is valuable for the risk assessment and management of antibiotic resistance.
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Affiliation(s)
- Renxin Zhao
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Jie Feng
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; State Environmental Protection Key Laboratory of Drinking Water Source Management and Technology, Shenzhen Research Academy of Environmental Sciences, Shenzhen 518001, China
| | - Jin Huang
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Xiaoyan Li
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Shenzhen Environmental Science and New Energy Laboratory, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
| | - Bing Li
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
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Zehentner B, Ardern Z, Kreitmeier M, Scherer S, Neuhaus K. A Novel pH-Regulated, Unusual 603 bp Overlapping Protein Coding Gene pop Is Encoded Antisense to ompA in Escherichia coli O157:H7 (EHEC). Front Microbiol 2020; 11:377. [PMID: 32265854 PMCID: PMC7103648 DOI: 10.3389/fmicb.2020.00377] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 02/20/2020] [Indexed: 12/23/2022] Open
Abstract
Antisense transcription is well known in bacteria. However, translation of antisense RNAs is typically not considered, as the implied overlapping coding at a DNA locus is assumed to be highly improbable. Therefore, such overlapping genes are systematically excluded in prokaryotic genome annotation. Here we report an exceptional 603 bp long open reading frame completely embedded in antisense to the gene of the outer membrane protein ompA. An active σ70 promoter, transcription start site (TSS), Shine-Dalgarno motif and rho-independent terminator were experimentally validated, providing evidence that this open reading frame has all the structural features of a functional gene. Furthermore, ribosomal profiling revealed translation of the mRNA, the protein was detected in Western blots and a pH-dependent phenotype conferred by the protein was shown in competitive overexpression growth experiments of a translationally arrested mutant versus wild type. We designate this novel gene pop (pH-regulated overlapping protein-coding gene), thus adding another example to the growing list of overlapping, protein coding genes in bacteria.
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Affiliation(s)
- Barbara Zehentner
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany
| | - Zachary Ardern
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany
| | - Michaela Kreitmeier
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany
| | - Siegfried Scherer
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany
- ZIEL – Institute for Food & Health, Technical University of Munich, Freising, Germany
| | - Klaus Neuhaus
- ZIEL – Institute for Food & Health, Technical University of Munich, Freising, Germany
- Core Facility Microbiome, ZIEL – Institute for Food & Health, Technical University of Munich, Freising, Germany
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Genomic Sequence Analysis of the Multidrug-Resistance Region of Avian Salmonella enterica serovar Indiana Strain MHYL. Microorganisms 2019; 7:microorganisms7080248. [PMID: 31404981 PMCID: PMC6723982 DOI: 10.3390/microorganisms7080248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 12/19/2022] Open
Abstract
A series of human and animal diseases that are caused by Salmonella infections pose a serious threat to human health and huge economic losses to the livestock industry. We found antibiotic resistance (AR) genes in the genome of 133 strains of S. Indiana from a poultry production site in Shandong Province, China. Salmonella enterica subsp. enterica serovar Indiana strain MHYL had multidrug-resistance (MDR) genes on its genome. Southern blot analysis was used to locate genes on the genomic DNA. High-throughput sequencing technology was used to determine the gene sequence of the MHYL genome. Areas containing MDR genes were mapped based on the results of gene annotation. The AR genes blaTEM, strA, tetA, and aac(6′)-Ib-cr were found on the MHYL genome. The resistance genes were located in two separate MDR regions, RR1 and RR2, containing type I integrons, and Tn7 transposons and multiple IS26 complex transposons with transposable functions. Portions of the MDR regions were determined to be highly homologous to the structure of plasmid pAKU_1 in S. enterica serovar Paratyphi A (accession number: AM412236), SGI11 in S. enterica serovar Typhimurium (accession number: KM023773), and plasmid pS414 in S. Indiana (accession No.: KC237285).
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10
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Liang W, Tang Y, Li G, Shen P, Tian Y, Jiang H, Jiang X, Lu Y. KlcA HS genes are ubiquitous in clinical, bla KPC-2-positive, Klebsiella pneumoniae isolates. INFECTION GENETICS AND EVOLUTION 2019; 70:84-89. [PMID: 30807842 DOI: 10.1016/j.meegid.2019.02.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 02/14/2019] [Accepted: 02/18/2019] [Indexed: 01/28/2023]
Abstract
Carbapenemase-producing Klebsiella pneumoniae has emerged and spread widely throughout the world. The mechanisms involved remain unclear. To provide insight, five plasmids were obtained from carbapenemase-producing K. pneumoniae clinical isolates. The five sequences were acquired, aligned and analyzed. In addition to the blaKPC-2 gene, which encodes beta lactamase, essentially all the plasmids contained a putative anti-restriction protein-encoding gene, KlcAHS. The KlcAHS gene was found in 98.2% of the blaKPC-2-positive, imipenem-resistant K. pneumoniae clinical isolates and in <1% of the blaKPC-2-negative control group. A searched of the GenBank database indicated that KlcAHS was mainly submitted by Chinese investigators beginning in 2010. Seventeen different KlcA amino acid sequences were found in the database using the restricting words: KlcA and Klebsiella pneumoniae. These sequences were used to generate a phylogenetic tree via MEGA6 software, revealing a distant evolutionary relationship between KlcAHS and other KlcAs. The secondary structure of KlcAHS, predicted with PROMALS3D software, exhibited highly conserved α-helices and β-strands. KlcAHS expressed anti-restriction activity in vivo. In summary, KlcAHS genes are ubiquitous in blaKPC-2-positive Klebsiella pneumoniae clinical isolates collected at Huashan Hospital, China. The KlcAHS protein possesses a secondary structure similar to that exhibited by anti-restriction proteins and displays anti-restriction activity. As such, KlcAHS is a probable factor in the accelerated spread of blaKPC-2 and carbapenem-resistance among clinical, K. pneumoniae isolates.
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Affiliation(s)
- Wei Liang
- Department of Laboratory Medicine, the Second People's Hospital of Lianyungang City, Jiangsu Province, China
| | - Yu Tang
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Gang Li
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Pinghua Shen
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yueru Tian
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Haoqin Jiang
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xiaofei Jiang
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Yuan Lu
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
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11
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The novel EHEC gene asa overlaps the TEGT transporter gene in antisense and is regulated by NaCl and growth phase. Sci Rep 2018; 8:17875. [PMID: 30552341 PMCID: PMC6294744 DOI: 10.1038/s41598-018-35756-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/08/2018] [Indexed: 12/02/2022] Open
Abstract
Only a few overlapping gene pairs are known in the best-analyzed bacterial model organism Escherichia coli. Automatic annotation programs usually annotate only one out of six reading frames at a locus, allowing only small overlaps between protein-coding sequences. However, both RNAseq and RIBOseq show signals corresponding to non-trivially overlapping reading frames in antisense to annotated genes, which may constitute protein-coding genes. The transcription and translation of the novel 264 nt gene asa, which overlaps in antisense to a putative TEGT (Testis-Enhanced Gene Transfer) transporter gene is detected in pathogenic E. coli, but not in two apathogenic E. coli strains. The gene in E. coli O157:H7 (EHEC) was further analyzed. An overexpression phenotype was identified in two stress conditions, i.e. excess in salt or arginine. For this, EHEC overexpressing asa was grown competitively against EHEC with a translationally arrested asa mutant gene. RT-qPCR revealed conditional expression dependent on growth phase, sodium chloride, and arginine. Two potential promoters were computationally identified and experimentally verified by reporter gene expression and determination of the transcription start site. The protein Asa was verified by Western blot. Close homologues of asa have not been found in protein databases, but bioinformatic analyses showed that it may be membrane associated, having a largely disordered structure.
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12
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Hücker SM, Vanderhaeghen S, Abellan-Schneyder I, Scherer S, Neuhaus K. The Novel Anaerobiosis-Responsive Overlapping Gene ano Is Overlapping Antisense to the Annotated Gene ECs2385 of Escherichia coli O157:H7 Sakai. Front Microbiol 2018; 9:931. [PMID: 29867840 PMCID: PMC5960689 DOI: 10.3389/fmicb.2018.00931] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/23/2018] [Indexed: 12/26/2022] Open
Abstract
Current notion presumes that only one protein is encoded at a given bacterial genetic locus. However, transcription and translation of an overlapping open reading frame (ORF) of 186 bp length were discovered by RNAseq and RIBOseq experiments. This ORF is almost completely embedded in the annotated L,D-transpeptidase gene ECs2385 of Escherichia coli O157:H7 Sakai in the antisense reading frame -3. The ORF is transcribed as part of a bicistronic mRNA, which includes the annotated upstream gene ECs2384, encoding a murein lipoprotein. The transcriptional start site of the operon resides 38 bp upstream of the ECs2384 start codon and is driven by a predicted σ70 promoter, which is constitutively active under different growth conditions. The bicistronic operon contains a ρ-independent terminator just upstream of the novel gene, significantly decreasing its transcription. The novel gene can be stably expressed as an EGFP-fusion protein and a translationally arrested mutant of ano, unable to produce the protein, shows a growth advantage in competitive growth experiments compared to the wild type under anaerobiosis. Therefore, the novel antisense overlapping gene is named ano (anaerobiosis responsive overlapping gene). A phylostratigraphic analysis indicates that ano originated very recently de novo by overprinting after the Escherichia/Shigella clade separated from other enterobacteria. Therefore, ano is one of the very rare cases of overlapping genes known in the genus Escherichia.
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Affiliation(s)
- Sarah M Hücker
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany
| | - Sonja Vanderhaeghen
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany
| | | | - Siegfried Scherer
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany.,Institute for Food & Health, Technical University of Munich, Freising, Germany
| | - Klaus Neuhaus
- Chair for Microbial Ecology, Technical University of Munich, Freising, Germany.,Core Facility Microbiome/NGS, Institute for Food & Health, Technical University of Munich, Freising, Germany
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Liang W, Xie Y, Xiong W, Tang Y, Li G, Jiang X, Lu Y. Anti-Restriction Protein, KlcA HS, Promotes Dissemination of Carbapenem Resistance. Front Cell Infect Microbiol 2017; 7:150. [PMID: 28512626 PMCID: PMC5411435 DOI: 10.3389/fcimb.2017.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 04/11/2017] [Indexed: 11/13/2022] Open
Abstract
Carbapenemase-producing Klebsiella pneumoniae (KPC) has emerged and spread throughout the world. A retrospective analysis was performed on carbapenem-resistant K. pneumoniae isolated at our teaching hospital during the period 2009–2010, when the initial outbreak occurred. To determine the mechanism(s) that underlies the increased infectivity exhibited by KPC, Multilocus Sequence Typing (MLST) was conducted. A series of plasmids was also extracted, sequenced and analyzed. Concurrently, the complete sequences of blaKPC−2-harboring plasmids deposited in GenBank were summarized and aligned. The blaKPC−2 and KlcAHS genes in the carbapenem-resistant K. pneumoniae isolates were examined. E. coli strains, carrying different Type I Restriction and Modification (RM) systems, were selected to study the interaction between RM systems, anti-RM systems and horizontal gene transfer (HGT). The ST11 clone predominated among 102 carbapenem-resistant K. pneumoniae isolates, all harbored the blaKPC−2 gene; 98% contained the KlcAHS gene. KlcAHS was one of the core genes in the backbone region of most blaKPC−2 carrying plasmids. Type I RM systems in the host bacteria reduced the rate of pHS10842 plasmid transformation by 30- to 40-fold. Presence of the anti-restriction protein, KlcAHS, on the other hand, increased transformation efficiency by 3- to 6-fold. These results indicate that RM systems can significantly restrict HGT. In contrast, KlcAHS can disrupt the RM systems and promote HGT by transformation. These findings suggest that the anti-restriction protein, KlcAHS, represents a novel mechanism that facilitates the increased transfer of blaKPC-2 and KlcAHS-carrying plasmids among K. pneumoniae strains.
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Affiliation(s)
- Wei Liang
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan UniversityShanghai, China
| | - Yingzhou Xie
- State Key Laboratory for Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiaotong UniversityShanghai, China
| | - Wei Xiong
- State Key Laboratory for Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiaotong UniversityShanghai, China
| | - Yu Tang
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan UniversityShanghai, China
| | - Gang Li
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan UniversityShanghai, China
| | - Xiaofei Jiang
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan UniversityShanghai, China
| | - Yuan Lu
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan UniversityShanghai, China
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14
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Fellner L, Simon S, Scherling C, Witting M, Schober S, Polte C, Schmitt-Kopplin P, Keim DA, Scherer S, Neuhaus K. Evidence for the recent origin of a bacterial protein-coding, overlapping orphan gene by evolutionary overprinting. BMC Evol Biol 2015; 15:283. [PMID: 26677845 PMCID: PMC4683798 DOI: 10.1186/s12862-015-0558-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/06/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Gene duplication is believed to be the classical way to form novel genes, but overprinting may be an important alternative. Overprinting allows entirely novel proteins to evolve de novo, i.e., formerly non-coding open reading frames within functional genes become expressed. Only three cases have been described for Escherichia coli. Here, a fourth example is presented. RESULTS RNA sequencing revealed an open reading frame weakly transcribed in cow dung, coding for 101 residues and embedded completely in the -2 reading frame of citC in enterohemorrhagic E. coli. This gene is designated novel overlapping gene, nog1. The promoter region fused to gfp exhibits specific activities and 5' rapid amplification of cDNA ends indicated the transcriptional start 40-bp upstream of the start codon. nog1 was strand-specifically arrested in translation by a nonsense mutation silent in citC. This Nog1-mutant showed a phenotype in competitive growth against wild type in the presence of MgCl2. Small differences in metabolite concentrations were also found. Bioinformatic analyses propose Nog1 to be inner membrane-bound and to possess at least one membrane-spanning domain. A phylogenetic analysis suggests that the orphan gene nog1 arose by overprinting after Escherichia/Shigella separated from the other γ-proteobacteria. CONCLUSIONS Since nog1 is of recent origin, non-essential, short, weakly expressed and only marginally involved in E. coli's central metabolism, we propose that this gene is in an initial stage of evolution. While we present specific experimental evidence for the existence of a fourth overlapping gene in enterohemorrhagic E. coli, we believe that this may be an initial finding only and overlapping genes in bacteria may be more common than is currently assumed by microbiologists.
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Affiliation(s)
- Lea Fellner
- Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85350, Freising, Germany.
| | - Svenja Simon
- Lehrstuhl für Datenanalyse und Visualisierung, Fachbereich Informatik und Informationswissenschaft, Universität Konstanz, Box 78, 78457, Constance, Germany.
| | - Christian Scherling
- Lehrstuhl für Ernährungsphysiologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Gregor-Mendel-Straße 2, D-85354, Freising, Germany.
| | - Michael Witting
- Research Unit Analytical BioGeoChemistry, Deutsches Forschungszentrum für Gesundheit und Umwelt GmbH, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85754, Neuherberg, Germany.
| | - Steffen Schober
- Institute of Communications Engineering, Universität Ulm, Albert-Einstein-Allee 43, 89081, Ulm, Germany. .,Present address: Blue Yonder GmbH, Ohiostraße 8, Karlsruhe, Germany.
| | - Christine Polte
- Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85350, Freising, Germany. .,Present address: Institut für Biochemie und Molekularbiologie, Universität Hamburg, Martin-Luther-King Platz 6, 20146, Hamburg, Germany.
| | - Philippe Schmitt-Kopplin
- Research Unit Analytical BioGeoChemistry, Deutsches Forschungszentrum für Gesundheit und Umwelt GmbH, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85754, Neuherberg, Germany.
| | - Daniel A Keim
- Lehrstuhl für Datenanalyse und Visualisierung, Fachbereich Informatik und Informationswissenschaft, Universität Konstanz, Box 78, 78457, Constance, Germany.
| | - Siegfried Scherer
- Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85350, Freising, Germany.
| | - Klaus Neuhaus
- Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85350, Freising, Germany.
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Zavilgelsky GB, Kotova VY, Melkina OE, Balabanov VP, Mindlin SZ. Proteolytic control of the antirestriction activity of Tn21, Tn5053, Tn5045, Tn501, and Tn402 non-conjugative transposons. Mol Biol 2015. [DOI: 10.1134/s0026893315020168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Zavilgelsky GB, Kotova VY, Melkina OE, Pustovoit KS. Antirestriction activity of the mercury resistance nonconjugative transposon Tn5053 is controlled by the protease ClpXP. RUSS J GENET+ 2014. [DOI: 10.1134/s1022795414090166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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