1
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Wellner SM, Alobaidallah MSA, Fei X, Herrero-Fresno A, Olsen JE. Genome-wide identification of fitness-genes in aminoglycoside-resistant Escherichia coli during antibiotic stress. Sci Rep 2024; 14:4163. [PMID: 38378700 PMCID: PMC10879529 DOI: 10.1038/s41598-024-54169-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/09/2024] [Indexed: 02/22/2024] Open
Abstract
Resistance against aminoglycosides is widespread in bacteria. This study aimed to identify genes that are important for growth of E. coli during aminoglycoside exposure, since such genes may be targeted to re-sensitize resistant E. coli to treatment. We constructed three transposon mutant libraries each containing > 230.000 mutants in E. coli MG1655 strains harboring streptomycin (aph(3″)-Ib/aph(6)-Id), gentamicin (aac(3)-IV), or neomycin (aph(3″)-Ia) resistance gene(s). Transposon Directed Insertion-site Sequencing (TraDIS), a combination of transposon mutagenesis and high-throughput sequencing, identified 56 genes which were deemed important for growth during streptomycin, 39 during gentamicin and 32 during neomycin exposure. Most of these fitness-genes were membrane-located (n = 55) and involved in either cell division, ATP-synthesis or stress response in the streptomycin and gentamicin exposed libraries, and enterobacterial common antigen biosynthesis or magnesium sensing/transport in the neomycin exposed library. For validation, eight selected fitness-genes/gene-clusters were deleted (minCDE, hflCK, clsA and cpxR associated with streptomycin and gentamicin resistance, and phoPQ, wecA, lpp and pal associated with neomycin resistance), and all mutants were shown to be growth attenuated upon exposure to the corresponding antibiotics. In summary, we identified genes that are advantageous in aminoglycoside-resistant E. coli during antibiotic stress. In addition, we increased the understanding of how aminoglycoside-resistant E. coli respond to antibiotic exposure.
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Affiliation(s)
- Sandra Marina Wellner
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg, Denmark
| | - Mosaed Saleh A Alobaidallah
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg, Denmark
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, 21423, Jeddah, Saudi Arabia
- King Abdullah International Medical Research Center, 22384, Jeddah, Saudi Arabia
| | - Xiao Fei
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg, Denmark
| | - Ana Herrero-Fresno
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, Universidade da Santiago de Compostela (USC), Campus Terra, 27002, Lugo, Spain.
| | - John Elmerdahl Olsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg, Denmark.
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2
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Wang G, Wang Q, Qi Q, Wang Q. Dynamic plasmid copy number control for synthetic biology. Trends Biotechnol 2024; 42:147-150. [PMID: 37689527 DOI: 10.1016/j.tibtech.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 09/11/2023]
Abstract
Plasmids that replicate independently from chromosomes are valuable genetic tools for biological research. Dynamic control of plasmid copy number facilitates flexible regulation of the gene of interest or the genetic circuit installed in the plasmid. This useful strategy is being integrated into synthetic biology for metabolic reprogramming and biosensing applications.
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Affiliation(s)
- Gege Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, PR China
| | - Qi Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, PR China
| | - Qingsheng Qi
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, PR China
| | - Qian Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, PR China.
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3
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Houtak G, Bouras G, Nepal R, Shaghayegh G, Cooksley C, Psaltis AJ, Wormald PJ, Vreugde S. The intra-host evolutionary landscape and pathoadaptation of persistent Staphylococcus aureus in chronic rhinosinusitis. Microb Genom 2023; 9. [PMID: 38010322 DOI: 10.1099/mgen.0.001128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023] Open
Abstract
Chronic rhinosinusitis (CRS) is a common chronic sinonasal mucosal inflammation associated with Staphylococcus aureus biofilm and relapsing infections. This study aimed to determine rates of S. aureus persistence and pathoadaptation in CRS patients by investigating the genomic relatedness and antibiotic resistance/tolerance in longitudinally collected S. aureus clinical isolates. A total of 68 S. aureus paired isolates (34 pairs) were sourced from 34 CRS patients at least 6 months apart. Isolates were grown into 48 h biofilms and tested for tolerance to antibiotics. A hybrid sequencing strategy was used to obtain high-quality reference-grade assemblies of all isolates. Single nucleotide variants (SNV) divergence in the core genome and sequence type clustering were used to analyse the relatedness of the isolate pairs. Single nucleotide and structural genome variations, plasmid similarity, and plasmid copy numbers between pairs were examined. Our analysis revealed that 41 % (14/34 pairs) of S. aureus isolates were persistent, while 59 % (20/34 pairs) were non-persistent. Persistent isolates showed episode-specific mutational changes over time with a bias towards events in genes involved in adhesion to the host and mobile genetic elements such as plasmids, prophages, and insertion sequences. Furthermore, a significant increase in the copy number of conserved plasmids of persistent strains was observed. This was accompanied by a significant increase in biofilm tolerance against all tested antibiotics, which was linked to a significant increase in biofilm biomass over time, indicating a potential biofilm pathoadaptive process in persistent isolates. In conclusion, our study provides important insights into the mutational changes during S. aureus persistence in CRS patients highlighting potential pathoadaptive mechanisms in S. aureus persistent isolates culminating in increased biofilm biomass.
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Affiliation(s)
- Ghais Houtak
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
| | - George Bouras
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
| | - Roshan Nepal
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
| | - Gohar Shaghayegh
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
| | - Clare Cooksley
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
| | - Alkis James Psaltis
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
| | - Peter-John Wormald
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
| | - Sarah Vreugde
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery - Otolaryngology Head and Neck Surgery, University of Adelaide and the Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Adelaide, Australia
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4
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Burton AT, Pospíšilová D, Sudzinova P, Snider EV, Burrage AM, Krásný L, Kearns DB. The alternative sigma factor SigN of Bacillus subtilis is intrinsically toxic. J Bacteriol 2023; 205:e0011223. [PMID: 37728605 PMCID: PMC10601692 DOI: 10.1128/jb.00112-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/13/2023] [Indexed: 09/21/2023] Open
Abstract
Sigma factors bind and direct the RNA polymerase core to specific promoter sequences, and alternative sigma factors direct transcription of different regulons of genes. Here, we study the pBS32 plasmid-encoded sigma factor SigN of Bacillus subtilis to determine how it contributes to DNA damage-induced cell death. We find that SigN causes cell death when expressed at high levels and does so in the absence of its regulon suggesting it is intrinsically toxic. One way toxicity was relieved was by curing the pBS32 plasmid, which eliminated a positive feedback loop that led to SigN hyper-accumulation. Another way toxicity was relieved was through mutating the chromosomally encoded transcriptional repressor protein AbrB, thereby derepressing a potent antisense transcript that antagonized SigN expression. SigN efficiently competed with the vegetative sigma factor SigA in vitro, and SigN accumulation in the absence of positive feedback reduced SigA-dependent transcription suggesting that toxicity may be due to competitive inhibition of one or more essential transcripts. Why B. subtilis encodes a toxic sigma factor is unclear but SigN may function in host-inhibition during lytic conversion, as phage lysogen genes are also encoded on pBS32. IMPORTANCE Alternative sigma factors activate entire regulons of genes to improve viability in response to environmental stimuli. The pBS32 plasmid-encoded alternative sigma factor SigN of Bacillus subtilis however, is activated by the DNA damage response and leads to cellular demise. Here we find that SigN impairs viability by hyper-accumulating and outcompeting the vegetative sigma factor for the RNA polymerase core. Why B. subtilis retains a plasmid with a deleterious alternative sigma factor is unknown.
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Affiliation(s)
- Aisha T. Burton
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Debora Pospíšilová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská, Prague, Czechia
| | - Petra Sudzinova
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská, Prague, Czechia
| | | | - Andrew M. Burrage
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Libor Krásný
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská, Prague, Czechia
| | - Daniel B. Kearns
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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5
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Synchrotron Radiation Circular Dichroism, a New Tool to Probe Interactions between Nucleic Acids Involved in the Control of ColE1-Type Plasmid Replication. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12052639] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Hfq is a bacterial master regulator which promotes the pairing of nucleic acids. Due to the high molecular weight of the complexes formed between nucleic acids and the amyloid form of the protein, it is difficult to analyze solely by a gel shift assay the complexes formed, as they all migrate at the same position in the gel. In addition, precise kinetics measurements are not possible using a gel shift assay. Here, we used a synchrotron-based biophysical approach, synchrotron radiation circular dichroism (SRCD), to probe the interaction of the Escherichia coli Hfq C-terminal amyloid region with nucleic acids involved in the control of ColE1-like plasmid replication. We observed that this C-terminal region of Hfq has an unexpected and significant effect on the annealing of nucleic acids involved in this process and, more importantly, on their alignment. Functional consequences of this newly discovered property of the Hfq amyloid region are discussed in terms of the biological significance of Hfq in the ColE1-type plasmid replication process and antibiotic resistance.
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6
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The Facts and Family Secrets of Plasmids That Replicate via the Rolling-Circle Mechanism. Microbiol Mol Biol Rev 2021; 86:e0022220. [PMID: 34878299 DOI: 10.1128/mmbr.00222-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Plasmids are self-replicative DNA elements that are transferred between bacteria. Plasmids encode not only antibiotic resistance genes but also adaptive genes that allow their hosts to colonize new niches. Plasmid transfer is achieved by conjugation (or mobilization), phage-mediated transduction, and natural transformation. Thousands of plasmids use the rolling-circle mechanism for their propagation (RCR plasmids). They are ubiquitous, have a high copy number, exhibit a broad host range, and often can be mobilized among bacterial species. Based upon the replicon, RCR plasmids have been grouped into several families, the best known of them being pC194 and pUB110 (Rep_1 family), pMV158 and pE194 (Rep_2 family), and pT181 and pC221 (Rep_trans family). Genetic traits of RCR plasmids are analyzed concerning (i) replication mediated by a DNA-relaxing initiator protein and its interactions with the cognate DNA origin, (ii) lagging-strand origins of replication, (iii) antibiotic resistance genes, (iv) mobilization functions, (v) replication control, performed by proteins and/or antisense RNAs, and (vi) the participating host-encoded functions. The mobilization functions include a relaxase initiator of transfer (Mob), an origin of transfer, and one or two small auxiliary proteins. There is a family of relaxases, the MOBV family represented by plasmid pMV158, which has been revisited and updated. Family secrets, like a putative open reading frame of unknown function, are reported. We conclude that basic research on RCR plasmids is of importance, and our perspectives contemplate the concept of One Earth because we should incorporate bacteria into our daily life by diminishing their virulence and, at the same time, respecting their genetic diversity.
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7
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Brantl S, Müller P. Cis- and Trans-Encoded Small Regulatory RNAs in Bacillus subtilis. Microorganisms 2021; 9:microorganisms9091865. [PMID: 34576762 PMCID: PMC8464778 DOI: 10.3390/microorganisms9091865] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022] Open
Abstract
Small regulatory RNAs (sRNAs) that act by base-pairing are the most abundant posttranscriptional regulators in all three kingdoms of life. Over the past 20 years, a variety of approaches have been employed to discover chromosome-encoded sRNAs in a multitude of bacterial species. However, although largely improved bioinformatics tools are available to predict potential targets of base-pairing sRNAs, it is still challenging to confirm these targets experimentally and to elucidate the mechanisms as well as the physiological role of their sRNA-mediated regulation. Here, we provide an overview of currently known cis- and trans-encoded sRNAs from B. subtilis with known targets and defined regulatory mechanisms and on the potential role of RNA chaperones that are or might be required to facilitate sRNA regulation in this important Gram-positive model organism.
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8
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Differential Chromosome- and Plasmid-Borne Resistance of Escherichia coli hfq Mutants to High Concentrations of Various Antibiotics. Int J Mol Sci 2021; 22:ijms22168886. [PMID: 34445592 PMCID: PMC8396180 DOI: 10.3390/ijms22168886] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 12/14/2022] Open
Abstract
The Hfq protein is a bacterial RNA chaperone, involved in many molecular interactions, including control of actions of various small RNA regulatory molecules. We found that the presence of Hfq was required for survival of plasmid-containing Escherichia coli cells against high concentrations of chloramphenicol (plasmid p27cmr), tetracycline (pSC101, pBR322) and ampicillin (pBR322), as hfq+ strains were more resistant to these antibiotics than the hfq-null mutant. In striking contrast, production of Hfq resulted in low resistance to high concentrations of kanamycin when the antibiotic-resistance marker was chromosome-borne, with deletion of hfq resulting in increasing bacterial survival. These results were observed both in solid and liquid medium, suggesting that antibiotic resistance is an intrinsic feature of these strains rather than a consequence of adaptation. Despite its major role as RNA chaperone, which also affects mRNA stability, Hfq was not found to significantly affect kan and tet mRNAs turnover. Nevertheless, kan mRNA steady-state levels were higher in the hfq-null mutant compared to the hfq+ strain, suggesting that Hfq can act as a repressor of kan expression.This observation does correlate with the enhanced resistance to high levels of kanamycin observed in the hfq-null mutant. Furthermore, dependency on Hfq for resistance to high doses of tetracycline was found to depend on plasmid copy number, which was only observed when the resistance marker was expressed from a low copy plasmid (pSC101) but not from a medium copy plasmid (pBR322). This suggests that Hfq may influence survival against high doses of antibiotics through mechanisms that remain to be determined. Studies with pBR322Δrom may also suggest an interplay between Hfq and Rom in the regulation of ColE1-like plasmid replication. Results of experiments with a mutant devoid of the part of the hfq gene coding for the C-terminal region of Hfq suggested that this region, as well as the N-terminal region, may be involved in the regulation of expression of antibiotic resistance in E. coli independently.
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9
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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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10
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Yang J, Wang HH, Lu Y, Yi LX, Deng Y, Lv L, Burrus V, Liu JH. A ProQ/FinO family protein involved in plasmid copy number control favours fitness of bacteria carrying mcr-1-bearing IncI2 plasmids. Nucleic Acids Res 2021; 49:3981-3996. [PMID: 33721023 PMCID: PMC8053102 DOI: 10.1093/nar/gkab149] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 02/03/2023] Open
Abstract
The plasmid-encoded colistin resistance gene mcr-1 challenges the use of polymyxins and poses a threat to public health. Although IncI2-type plasmids are the most common vector for spreading the mcr-1 gene, the mechanisms by which these plasmids adapt to host bacteria and maintain resistance genes remain unclear. Herein, we investigated the regulatory mechanism for controlling the fitness cost of an IncI2 plasmid carrying mcr-1. A putative ProQ/FinO family protein encoded by the IncI2 plasmid, designated as PcnR (plasmid copy number repressor), balances the mcr-1 expression and bacteria fitness by repressing the plasmid copy number. It binds to the first stem-loop structure of the repR mRNA to repress RepA expression, which differs from any other previously reported plasmid replication control mechanism. Plasmid invasion experiments revealed that pcnR is essential for the persistence of the mcr-1-bearing IncI2 plasmid in the bacterial populations. Additionally, single-copy mcr-1 gene still exerted a fitness cost to host bacteria, and negatively affected the persistence of the IncI2 plasmid in competitive co-cultures. These findings demonstrate that maintaining mcr-1 plasmid at a single copy is essential for its persistence, and explain the significantly reduced prevalence of mcr-1 following the ban of colistin as a growth promoter in China.
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Affiliation(s)
- Jun Yang
- College of Veterinary Medicine, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs,Center for Emerging and Zoonotic Diseases, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Hai-Hong Wang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Yaoyao Lu
- College of Veterinary Medicine, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs,Center for Emerging and Zoonotic Diseases, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Ling-Xian Yi
- College of Veterinary Medicine, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs,Center for Emerging and Zoonotic Diseases, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou 510275, China
| | - Luchao Lv
- College of Veterinary Medicine, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs,Center for Emerging and Zoonotic Diseases, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Vincent Burrus
- Département de biologie, Université de Sherbrooke, Sherbrooke J1K 2R1, Québec, Canada
| | - Jian-Hua Liu
- College of Veterinary Medicine, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs,Center for Emerging and Zoonotic Diseases, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
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11
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Lysinibacillus sphaericus III(3)7 and Plasmid Vector pMK4: New Challenges in Cloning Platforms. MICROBIOLOGY RESEARCH 2021. [DOI: 10.3390/microbiolres12020031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The acquisition and especially the maintenance of a plasmid usually brings a fitness cost that reduces the reproductive rate of the bacterial host; for strains like Lysinibacillus sphaericus III(3)7, which possesses important environmental properties, this alteration along with morphological changes and reduced sporulation rates may exert a negative effect on metabolic studies using plasmids as cloning platforms. The aim of this study is to approach the metabolic behavior of pMK4-bearing cells of L. sphaericus III(3)7 through the use of bioinformatic and in vitro analyses. An incompatibility model between the pMK4 vector and a predicted megaplasmid, pBsph, inside III(3)7 cells was constructed based on an incA region. Additionally, in vitro long-term plasmid stability was not found in plasmid-bearing cells. Alignments between replicons, mobile genetic elements and RNA-RNA interactions were assessed, pairwise alignment visualization, graphic models and morphological changes were evaluated by SEM. Metabolite analysis was done through HPLC coupled to a Q-TOF 6545, and electrospray ionization was used, finally, Aedes aegypti and Culex quinquefasciatus larvae were used for larvicidal activity assessment. Results found, a decreased growth rate, spore formation reduction and morphological changes, which supported the idea of metabolic cost exerted by pMK4. An incompatibility between pMK4 and pBsph appears to take place inside L. sphaericus III(3)7 cells, however, further in vitro studies are needed to confirm it.
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12
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Guimarães VA, Le Scornet A, Khemici V, Hausmann S, Armitano J, Prados J, Jousselin A, Manzano C, Linder P, Redder P. RNase J1 and J2 Are Host-Encoded Factors for Plasmid Replication. Front Microbiol 2021; 12:586886. [PMID: 34017314 PMCID: PMC8129170 DOI: 10.3389/fmicb.2021.586886] [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: 07/24/2020] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
Plasmids need to ensure their transmission to both daughter-cells when their host divides, but should at the same time avoid overtaxing their hosts by directing excessive host-resources toward production of plasmid factors. Naturally occurring plasmids have therefore evolved regulatory mechanisms to restrict their copy-number in response to the volume of the cytoplasm. In many plasmid families, copy-number control is mediated by a small plasmid-specified RNA, which is continuously produced and rapidly degraded, to ensure that its concentration is proportional to the current plasmid copy-number. We show here that pSA564 from the RepA_N-family is regulated by a small antisense RNA (RNA1), which, when over-expressed in trans, blocks plasmid replication and cures the bacterial host. The 5' untranslated region (5'UTR) of the plasmid replication initiation gene (repA) potentially forms two mutually exclusive secondary structures, ON and OFF, where the latter both sequesters the repA ribosome binding site and acts as a rho-independent transcriptional terminator. Duplex formation between RNA1 and the 5'UTR shifts the equilibrium to favor the putative OFF-structure, enabling a single small RNA to down-regulate repA expression at both transcriptional and translational levels. We further examine which sequence elements on the antisense RNA and on its 5'UTR target are needed for this regulation. Finally, we identify the host-encoded exoribonucleases RNase J1 and J2 as the enzymes responsible for rapidly degrading the replication-inhibiting section of RNA1. This region accumulates and blocks RepA expression in the absence of either RNase J1 or J2, which are therefore essential host factors for pSA564 replication in Staphylococcus aureus.
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Affiliation(s)
- Vanessa Andrade Guimarães
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Alexandre Le Scornet
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
| | - Vanessa Khemici
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Stéphane Hausmann
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Joshua Armitano
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Julien Prados
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ambre Jousselin
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
| | - Caroline Manzano
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Peter Redder
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
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13
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Marincola G, Jaschkowitz G, Kieninger AK, Wencker FDR, Feßler AT, Schwarz S, Ziebuhr W. Plasmid-Chromosome Crosstalk in Staphylococcus aureus: A Horizontally Acquired Transcription Regulator Controls Polysaccharide Intercellular Adhesin-Mediated Biofilm Formation. Front Cell Infect Microbiol 2021; 11:660702. [PMID: 33829001 PMCID: PMC8019970 DOI: 10.3389/fcimb.2021.660702] [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: 01/29/2021] [Accepted: 03/02/2021] [Indexed: 11/24/2022] Open
Abstract
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) of clonal complex CC398 typically carry various antimicrobial resistance genes, many of them located on plasmids. In the bovine LA-MRSA isolate Rd11, we previously identified plasmid pAFS11 in which resistance genes are co-localized with a novel ica-like gene cluster, harboring genes required for polysaccharide intercellular adhesin (PIA)-mediated biofilm formation. The ica genes on pAFS11 were acquired in addition to a pre-existing ica locus on the S. aureus Rd11 chromosomal DNA. Both loci consist of an icaADBC operon and icaR, encoding a corresponding icaADBC repressor. Despite carrying two biofilm gene copies, strain Rd11 did not produce PIA and transformation of pAFS11 into another S. aureus strain even slightly diminished PIA-mediated biofilm formation. By focusing on the molecular background of the biofilm-negative phenotype of pAFS11-carrying S. aureus, we identified the pAFS11-borne ica locus copy as functionally fully active. However, transcription of both plasmid- and core genome-derived icaADBC operons were efficiently suppressed involving IcaR. Surprisingly, although being different on the amino acid sequence level, the two IcaR repressor proteins are mutually replaceable and are able to interact with the icaA promoter region of the other copy. We speculate that this regulatory crosstalk causes the biofilm-negative phenotype in S. aureus Rd11. The data shed light on an unexpected regulatory interplay between pre-existing and newly acquired DNA traits in S. aureus. This also raises interesting general questions regarding functional consequences of gene transfer events and their putative implications for the adaptation and evolution of bacterial pathogens.
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Affiliation(s)
- Gabriella Marincola
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Greta Jaschkowitz
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Ann-Katrin Kieninger
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Freya D R Wencker
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Andrea T Feßler
- Centre for Infection Medicine, Institute of Microbiology and Epizootics, Free University of Berlin, Berlin, Germany
| | - Stefan Schwarz
- Centre for Infection Medicine, Institute of Microbiology and Epizootics, Free University of Berlin, Berlin, Germany
| | - Wilma Ziebuhr
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
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14
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Kim JW, Bugata V, Cortés-Cortés G, Quevedo-Martínez G, Camps M. Mechanisms of Theta Plasmid Replication in Enterobacteria and Implications for Adaptation to Its Host. EcoSal Plus 2020; 9:10.1128/ecosalplus.ESP-0026-2019. [PMID: 33210586 PMCID: PMC7724965 DOI: 10.1128/ecosalplus.esp-0026-2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Indexed: 11/20/2022]
Abstract
Plasmids are autonomously replicating sequences that help cells adapt to diverse stresses. Theta plasmids are the most frequent plasmid class in enterobacteria. They co-opt two host replication mechanisms: replication at oriC, a DnaA-dependent pathway leading to replisome assembly (theta class A), and replication fork restart, a PriA-dependent pathway leading to primosome assembly through primer extension and D-loop formation (theta classes B, C, and D). To ensure autonomy from the host's replication and to facilitate copy number regulation, theta plasmids have unique mechanisms of replication initiation at the plasmid origin of replication (ori). Tight plasmid copy number regulation is essential because of the major and direct impact plasmid gene dosage has on gene expression. The timing of plasmid replication and segregation are also critical for optimizing plasmid gene expression. Therefore, we propose that plasmid replication needs to be understood in its biological context, where complex origins of replication (redundant origins, mosaic and cointegrated replicons), plasmid segregation, and toxin-antitoxin systems are often present. Highlighting their tight functional integration with ori function, we show that both partition and toxin-antitoxin systems tend to be encoded in close physical proximity to the ori in a large collection of Escherichia coli plasmids. We also propose that adaptation of plasmids to their host optimizes their contribution to the host's fitness while restricting access to broad genetic diversity, and we argue that this trade-off between adaptation to host and access to genetic diversity is likely a determinant factor shaping the distribution of replicons in populations of enterobacteria.
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Affiliation(s)
- Jay W Kim
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA, 95064
| | - Vega Bugata
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA, 95064
| | - Gerardo Cortés-Cortés
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA, 95064
| | - Giselle Quevedo-Martínez
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA, 95064
| | - Manel Camps
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA, 95064
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15
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Mediati DG, Wu S, Wu W, Tree JJ. Networks of Resistance: Small RNA Control of Antibiotic Resistance. Trends Genet 2020; 37:35-45. [PMID: 32951948 DOI: 10.1016/j.tig.2020.08.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/13/2020] [Accepted: 08/20/2020] [Indexed: 12/20/2022]
Abstract
The golden age of antibiotics has passed, and the threat of untreatable antimicrobial resistant infections is now a reality for many individuals. Understanding how bacteria resist antimicrobial treatment and regulate gene expression in response to antibiotics is an important step towards combating resistance. In this review we focus on a ubiquitous class of bacterial gene regulators termed regulatory small RNAs (sRNAs) and how they contribute to antimicrobial resistance and tolerance. Small RNAs have notable roles in modulating the composition of the bacterial envelope, and through these functions control intrinsic antimicrobial resistance in many human pathogens. Recent technical advances that allow profiling of the 'sRNA interactome' have revealed a complex post-transcriptional network of sRNA interactions that can be used to identify network hubs and regulatory bottlenecks. Sequence-specific inhibition of these sRNAs with programmable RNA-targeting therapeutics may present avenues for treating antimicrobial resistant pathogens or resensitizing to our current antibiotics.
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Affiliation(s)
- Daniel G Mediati
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Sylvania Wu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Winton Wu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jai J Tree
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
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16
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Oliva M, Calia C, Ferrara M, D'Addabbo P, Scrascia M, Mulè G, Monno R, Pazzani C. Antimicrobial resistance gene shuffling and a three-element mobilisation system in the monophasic Salmonella typhimurium strain ST1030. Plasmid 2020; 111:102532. [PMID: 32853586 DOI: 10.1016/j.plasmid.2020.102532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 11/30/2022]
Abstract
In this study we describe the genetic elements and the antimicrobial resistance units (RUs) harboured by the Salmonella Typhimurium monophasic variant 1,4,[5],12:i:- strain ST1030. Of the three identified RUs two were chromosomal, RU1 (IS26-blaTEM-1-IS26-strAB-sul2- IS26) and RU2 (IS26-tetR(B)-tetA(B)-ΔIS26), and one, RU3 (a sul3-associated class 1 integron with cassette array dfrA12-orfF-aadA2-cmlA1-aadA1), was embedded in a Tn21-derived element harboured by the conjugative I1 plasmid pST1030-1A. IS26 elements mediated the antimicrobial resistance gene (ARG) shuffling and this gave rise to pST1030-1A derivatives with different sets of ARGs. ST1030 also harboured two ColE1-like plasmids of which one, pST1030-2A, was mobilisable and the target of an intracellular translocation of the Tn21-derived element; the second (pST1030-3) was an orphan mob-associated oriT plasmid co-transferred with pST1030-1A and pST1030-2A. pST1030-2A and pST1030-3 also carried a parA gene and a type III restriction modification system, respectively. Overall analysis of our data reinforces the role played by IS26, Tn21-derived elements and non-conjugative plasmids in the spread of ARGs and supplies the first evidence, at least in Salmonella, for the identification of a natural isolate harbouring a three-element mobilisation system in the same cell.
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Affiliation(s)
- M Oliva
- Department of Biology, University of Bari, via Orabona, 4, 70125 Bari, Italy
| | - C Calia
- Department of Biology, University of Bari, via Orabona, 4, 70125 Bari, Italy
| | - M Ferrara
- Institute of Sciences of Food Production, National Research Council of Italy (ISPA-CNR), Via G. Amendola 122/O, 70126 Bari, Italy
| | - P D'Addabbo
- Department of Biology, University of Bari, via Orabona, 4, 70125 Bari, Italy
| | - M Scrascia
- Department of Biology, University of Bari, via Orabona, 4, 70125 Bari, Italy
| | - G Mulè
- Institute of Sciences of Food Production, National Research Council of Italy (ISPA-CNR), Via G. Amendola 122/O, 70126 Bari, Italy
| | - R Monno
- Department of Basic Medical Sciences Neurosciences and Sense Organs Medical Faculty, University of Bari Piazza G. Cesare Policlinico, 70124 Bari, Italy
| | - C Pazzani
- Department of Biology, University of Bari, via Orabona, 4, 70125 Bari, Italy.
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17
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Abstract
Bacteriophages are the most abundant biological entities in the biosphere and are a source of uncharacterized biological mechanisms and genetic tools. Here, we identify segments of phage genomes that are used for stable extrachromosomal replication in the prophage state. Autonomous replication of some of these phages requires a RepA-like protein, although most lack repA and use RNA-based systems for replication initiation. We describe a suite of plasmids based on these prophage replication functions that vary in copy number, stability, host range, and compatibility. These plasmids expand the toolbox available for genetic manipulation of Mycobacterium and other Actinobacteria, including Gordonia terrae. Temperate bacteriophages are common and establish lysogens of their bacterial hosts in which the prophage is stably inherited. It is typical for such prophages to be integrated into the bacterial chromosome, but extrachromosomally replicating prophages have been described also, with the best characterized being the Escherichia coli phage P1 system. Among the large collection of sequenced mycobacteriophages, more than half are temperate or predicted to be temperate, most of which code for a tyrosine or serine integrase that promotes site-specific prophage integration. However, within the large group of 621 cluster A temperate phages, ∼20% lack an integration cassette, which is replaced with a parABS partitioning system. A subset of these phages carry genes coding for a RepA-like protein (RepA phages), which we show here is necessary and sufficient for autonomous extrachromosomal replication. The non-RepA phages appear to replicate using an RNA-based system, as a parABS-proximal region expressing a noncoding RNA is required for replication. Both RepA and non-RepA phage-based plasmids replicate at one or two copies per cell, transform both Mycobacterium smegmatis and Mycobacterium tuberculosis, and are compatible with pAL5000-derived oriM and integration-proficient plasmid vectors. Characterization of these phage-based plasmids offers insights into the variability of lysogenic maintenance systems and provides a large suite of plasmids for actinobacterial genetics that vary in stability, copy number, compatibility, and host range.
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18
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Ramirez MS, Iriarte A, Reyes-Lamothe R, Sherratt DJ, Tolmasky ME. Small Klebsiella pneumoniae Plasmids: Neglected Contributors to Antibiotic Resistance. Front Microbiol 2019; 10:2182. [PMID: 31616398 PMCID: PMC6764390 DOI: 10.3389/fmicb.2019.02182] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 09/05/2019] [Indexed: 12/15/2022] Open
Abstract
Klebsiella pneumoniae is the causative agent of community- and, more commonly, hospital-acquired infections. Infections caused by this bacterium have recently become more dangerous due to the acquisition of multiresistance to antibiotics and the rise of hypervirulent variants. Plasmids usually carry genes coding for resistance to antibiotics or virulence factors, and the recent sequence of complete K. pneumoniae genomes showed that most strains harbor many of them. Unlike large plasmids, small, usually high copy number plasmids, did not attract much attention. However, these plasmids may include genes coding for specialized functions, such as antibiotic resistance, that can be expressed at high levels due to gene dosage effect. These genes may be part of mobile elements that not only facilitate their dissemination but also participate in plasmid evolution. Furthermore, high copy number plasmids may also play a role in evolution by allowing coexistence of mutated and non-mutated versions of a gene, which helps to circumvent the constraints imposed by trade-offs after certain genes mutate. Most K. pneumoniae plasmids 25-kb or smaller replicate by the ColE1-type mechanism and many of them are mobilizable. The transposon Tn1331 and derivatives were found in a high percentage of these plasmids. Another transposon that was found in representatives of this group is the bla KPC-containing Tn4401. Common resistance determinants found in these plasmids were aac(6')-Ib and genes coding for β-lactamases including carbapenemases.
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Affiliation(s)
- Maria S. Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Sciences, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA, United States
| | - Andrés Iriarte
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Facultad de Medicina, Universidad de la República de Uruguay, Montevideo, Uruguay
| | | | - David J. Sherratt
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Sciences, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA, United States
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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19
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Malabirade A, Partouche D, El Hamoui O, Turbant F, Geinguenaud F, Recouvreux P, Bizien T, Busi F, Wien F, Arluison V. Revised role for Hfq bacterial regulator on DNA topology. Sci Rep 2018; 8:16792. [PMID: 30429520 PMCID: PMC6235962 DOI: 10.1038/s41598-018-35060-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/26/2018] [Indexed: 12/11/2022] Open
Abstract
Hfq is a pleiotropic regulator that mediates several aspects of bacterial RNA metabolism. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, usually via its interaction with small regulatory RNA. Besides these RNA-related functions, Hfq has also been described as one of the nucleoid associated proteins shaping the bacterial chromosome. Therefore, Hfq appears as a versatile nucleic acid-binding protein, which functions are probably even more numerous than those initially suggested. For instance, E. coli Hfq, and more precisely its C-terminal region (CTR), has been shown to induce DNA compaction into a condensed form. In this paper, we establish that DNA induces Hfq-CTR amyloidogenesis, resulting in a change of DNA local conformation. Furthermore, we clarify the effect of Hfq on DNA topology. Our results evidence that, even if the protein has a strong propensity to compact DNA thanks to its amyloid region, it does not affect overall DNA topology. We confirm however that hfq gene disruption influences plasmid supercoiling in vivo, indicating that the effect on DNA topology in former reports was indirect. Most likely, this effect is related to small regulatory sRNA-Hfq-based regulation of another protein that influences DNA supercoiling, possibly a nucleoid associated protein such as H-NS or Dps. Finally, we hypothesise that this indirect effect on DNA topology explains, at least partially, the previously reported effect of Hfq on plasmid replication efficiency.
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Affiliation(s)
- Antoine Malabirade
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
| | - David Partouche
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France.,Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP48, 91192, Gif-sur-Yvette, France
| | - Omar El Hamoui
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP48, 91192, Gif-sur-Yvette, France
| | - Florian Turbant
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
| | | | | | - Thomas Bizien
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP48, 91192, Gif-sur-Yvette, France
| | - Florent Busi
- Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR8251, Université Paris Diderot, 75013, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, 75013, Paris, France
| | - Frank Wien
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP48, 91192, Gif-sur-Yvette, France
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France. .,Université Paris Diderot, Sorbonne Paris Cité, 75013, Paris, France.
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20
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Partridge SR, Kwong SM, Firth N, Jensen SO. Mobile Genetic Elements Associated with Antimicrobial Resistance. Clin Microbiol Rev 2018; 31:e00088-17. [PMID: 30068738 PMCID: PMC6148190 DOI: 10.1128/cmr.00088-17] [Citation(s) in RCA: 1174] [Impact Index Per Article: 195.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Strains of bacteria resistant to antibiotics, particularly those that are multiresistant, are an increasing major health care problem around the world. It is now abundantly clear that both Gram-negative and Gram-positive bacteria are able to meet the evolutionary challenge of combating antimicrobial chemotherapy, often by acquiring preexisting resistance determinants from the bacterial gene pool. This is achieved through the concerted activities of mobile genetic elements able to move within or between DNA molecules, which include insertion sequences, transposons, and gene cassettes/integrons, and those that are able to transfer between bacterial cells, such as plasmids and integrative conjugative elements. Together these elements play a central role in facilitating horizontal genetic exchange and therefore promote the acquisition and spread of resistance genes. This review aims to outline the characteristics of the major types of mobile genetic elements involved in acquisition and spread of antibiotic resistance in both Gram-negative and Gram-positive bacteria, focusing on the so-called ESKAPEE group of organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli), which have become the most problematic hospital pathogens.
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Affiliation(s)
- Sally R Partridge
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, New South Wales, Australia
| | - Stephen M Kwong
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Neville Firth
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Slade O Jensen
- Microbiology and Infectious Diseases, School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- Antibiotic Resistance & Mobile Elements Group, Ingham Institute for Applied Medical Research, Sydney, New South Wales, Australia
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21
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Berger M, Berger P, Denamur E, Mellmann A, Dobrindt U. Core elements of the vegetative replication control of the Inc1 plasmid pO104_90 of Escherichia coli O104:H4 also regulate its transfer frequency. Int J Med Microbiol 2018; 308:962-968. [DOI: 10.1016/j.ijmm.2018.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/25/2018] [Accepted: 07/10/2018] [Indexed: 01/18/2023] Open
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22
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Hamidian M, Hall RM. Genetic structure of four plasmids found in Acinetobacter baumannii isolate D36 belonging to lineage 2 of global clone 1. PLoS One 2018; 13:e0204357. [PMID: 30260997 PMCID: PMC6160057 DOI: 10.1371/journal.pone.0204357] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 09/06/2018] [Indexed: 11/24/2022] Open
Abstract
Four plasmids ranging in size from 4.7 to 44.7 kb found in the extensively antibiotic resistant Acinetobacter baumannii isolate D36 that belongs to lineage 2 of global clone 1 were examined. D36 includes two cryptic plasmids and two carrying antibiotic resistance genes. The smallest plasmid pD36-1 (4.7 kb) carries no resistance genes but includes mobA and mobC mobilisation genes related to those found in pRAY* (pD36-2, 6,078 bp) that also carries the aadB gentamicin, kanamycin and tobramycin resistance gene cassette. These two plasmids do not encode a Rep protein. Plasmid pRAY* was found to be mobilised at high frequency by the large conjugative plasmid pA297-3 but a pRAY* derivative lacking the mobA and mobC genes was not. The two larger plasmids, pD36-3 and pD36-4, encode Rep_3 family proteins (Pfam1051). The cryptic plasmid pD36-3 (6.2 kb) has RepAci1 and pD36-4 (44.7 kb) encodes two novel Rep_3 family proteins suggesting a co-integrate. Plasmid pD36-4 includes the sul2 sulfonamide resistance gene, the aphA1a kanamycin/neomycin resistance gene in Tn4352::ISAba1 and a mer module in a hybrid Tn501/Tn1696 transposon conferring resistance to mercuric ions. New examples of dif modules flanked by pdif sites (XerC-XerD binding sites) that are part of many A. baumannii plasmids were also identified in pD36-3 and pD36-4 which carry three and two dif modules, respectively. Homologs of three dif modules, the sup sulphate permease module in pD36-3, and of the abkAB toxin-antitoxin module and the orf module in pD36-4, were found in different contexts in diverse Acinetobacter plasmids, consistent with module mobility. A novel insertion sequence named ISAba32 found next to the pdif site in the abkAB dif module is related to members of the ISAjo2 group which also are associated with the pdif sites of dif modules. Plasmids found in D36 were also found in some other members of GC1 lineage 2.
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Affiliation(s)
- Mohammad Hamidian
- The ithree institute, University of Technology Sydney, Ultimo, New South Wales, Australia
- * E-mail:
| | - Ruth M. Hall
- School of Life and Environmental Sciences, The University of Sydney, New South Wales, Australia
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23
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Fournes F, Val ME, Skovgaard O, Mazel D. Replicate Once Per Cell Cycle: Replication Control of Secondary Chromosomes. Front Microbiol 2018; 9:1833. [PMID: 30131796 PMCID: PMC6090056 DOI: 10.3389/fmicb.2018.01833] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/23/2018] [Indexed: 12/13/2022] Open
Abstract
Faithful vertical transmission of genetic information, especially of essential core genes, is a prerequisite for bacterial survival. Hence, replication of all the replicons is tightly controlled to ensure that all daughter cells get the same genome copy as their mother cell. Essential core genes are very often carried by the main chromosome. However they can occasionally be found on secondary chromosomes, recently renamed chromids. Chromids have evolved from non-essential megaplasmids, and further acquired essential core genes and a genomic signature closed to that of the main chromosome. All chromids carry a plasmidic replication origin, belonging so far to either the iterons or repABC type. Based on these differences, two categories of chromids have been distinguished. In this review, we focus on the replication initiation controls of these two types of chromids. We show that the sophisticated mechanisms controlling their replication evolved from their plasmid counterparts to allow a timely controlled replication, occurring once per cell cycle.
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Affiliation(s)
- Florian Fournes
- Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Institut Pasteur, Paris, France.,UMR3525, Centre National de la Recherche Scientifique, Paris, France
| | - Marie-Eve Val
- Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Institut Pasteur, Paris, France.,UMR3525, Centre National de la Recherche Scientifique, Paris, France
| | - Ole Skovgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Didier Mazel
- Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Institut Pasteur, Paris, France.,UMR3525, Centre National de la Recherche Scientifique, Paris, France
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24
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Pluta R, Espinosa M. Antisense and yet sensitive: Copy number control of rolling circle-replicating plasmids by small RNAs. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1500. [PMID: 30074293 DOI: 10.1002/wrna.1500] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/27/2018] [Accepted: 07/01/2018] [Indexed: 12/27/2022]
Abstract
Bacterial plasmids constitute a wealth of shared DNA amounting to about 20% of the total prokaryotic pangenome. Plasmids replicate autonomously and control their replication by maintaining a fairly constant number of copies within a given host. Plasmids should acquire a good fitness to their hosts so that they do not constitute a genetic load. Here we review some basic concepts in plasmid biology, pertaining to the control of replication and distribution of plasmid copies among daughter cells. A particular class of plasmids is constituted by those that replicate by the rolling circle mode (rolling circle-replicating [RCR]-plasmids). They are small double-stranded DNA molecules, with a rather high number of copies in the original host. RCR-plasmids control their replication by means of a small short-lived antisense RNA, alone or in combination with a plasmid-encoded transcriptional repressor protein. Two plasmid prototypes have been studied in depth, namely the staphylococcal plasmid pT181 and the streptococcal plasmid pMV158, each corresponding to the two types of replication control circuits, respectively. We further discuss possible applications of the plasmid-encoded antisense RNAs and address some future directions that, in our opinion, should be pursued in the study of these small molecules. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Radoslaw Pluta
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
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25
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Standley MS, Million-Weaver S, Alexander DL, Hu S, Camps M. Genetic control of ColE1 plasmid stability that is independent of plasmid copy number regulation. Curr Genet 2018; 65:179-192. [PMID: 29909438 DOI: 10.1007/s00294-018-0858-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 02/07/2023]
Abstract
ColE1-like plasmid vectors are widely used for expression of recombinant genes in E. coli. For these vectors, segregation of individual plasmids into daughter cells during cell division appears to be random, making them susceptible to loss over time when no mechanisms ensuring their maintenance are present. Here we use the plasmid pGFPuv in a recA relA strain as a sensitized model to study factors affecting plasmid stability in the context of recombinant gene expression. We find that in this model, plasmid stability can be restored by two types of genetic modifications to the plasmid origin of replication (ori) sequence: point mutations and a novel 269 nt duplication at the 5' end of the plasmid ori, which we named DAS (duplicated anti-sense) ori. Combinations of these modifications produce a range of copy numbers and of levels of recombinant expression. In direct contradiction with the classic random distribution model, we find no correlation between increased plasmid copy number and increased plasmid stability. Increased stability cannot be explained by reduced levels of recombinant gene expression either. Our observations would be more compatible with a hybrid clustered and free-distribution model, which has been recently proposed based on detection of individual plasmids in vivo using super-resolution fluorescence microscopy. This work suggests a role for the plasmid ori in the control of segregation of ColE1 plasmids that is distinct from replication initiation, opening the door for the genetic regulation of plasmid stability as a strategy aimed at enhancing large-scale recombinant gene expression or bioremediation.
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Affiliation(s)
- Melissa S Standley
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Samuel Million-Weaver
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
- College of Engineering, University of Wisconsin-Madison, Madison, 53706, USA
| | - David L Alexander
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
- Department of Biomolecular Engineering, UCSC, Santa Cruz, USA
| | - Shuai Hu
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Manel Camps
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA.
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Ruiz-Masó JÁ, Luengo LM, Moreno-Córdoba I, Díaz-Orejas R, Del Solar G. Successful Establishment of Plasmids R1 and pMV158 in a New Host Requires the Relief of the Transcriptional Repression of Their Essential rep Genes. Front Microbiol 2017; 8:2367. [PMID: 29250051 PMCID: PMC5717011 DOI: 10.3389/fmicb.2017.02367] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/16/2017] [Indexed: 11/13/2022] Open
Abstract
Although differing in size, encoded traits, host range, and replication mechanism, both narrow-host-range theta-type conjugative enterobacterial plasmid R1 and promiscuous rolling-circle-type mobilizable streptococcal plasmid pMV158 encode a transcriptional repressor protein, namely CopB in R1 and CopG in pMV158, involved in replication control. The gene encoding CopB or CopG is cotranscribed with a downstream gene that encodes the replication initiator Rep protein of the corresponding plasmid. However, whereas CopG is an auto-repressor that inhibits transcription of the entire copG-repB operon, CopB is expressed constitutively and represses a second, downstream promoter that directs transcription of repA. As a consequence of the distinct regulatory pathways implied by CopB and CopG, these repressor proteins play a different role in control of plasmid replication during the steady state: while CopB has an auxiliary role by keeping repressed the regulated promoter whenever the plasmid copy number is above a low threshold, CopG plays a primary role by acting coordinately with RNAII. Here, we have studied the role of the regulatory circuit mediated by these transcriptional repressors during the establishment of these two plasmids in a new host cell, and found that excess Cop repressor molecules in the recipient cell result in a severe decrease in the frequency and/or the velocity of appearance of transformant colonies for the cognate plasmid but not for unrelated plasmids. Using the pMV158 replicon as a model system, together with highly sensitive real-time qPCR and inverse PCR methods, we have also analyzed the effect of CopG on the kinetics of repopulation of the plasmid in Streptococcus pneumoniae. We show that, whereas in the absence of CopG pMV158 repopulation occurs mainly during the first 45 min following plasmid transfer, the presence of the transcriptional repressor in the recipient cell severely impairs the replicon repopulation and makes the plasmid replicate at approximately the same rate as the chromosome at any time after transformation, which results in maximal plasmid loss rate in the absence of selection. Overall, these findings indicate that unrepressed activity of the Cop-regulated promoter is crucial for the successful colonization of the recipient bacterial cells by the plasmid.
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Affiliation(s)
- José Á Ruiz-Masó
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Luis M Luengo
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Inmaculada Moreno-Córdoba
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Ramón Díaz-Orejas
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Gloria Del Solar
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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27
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Kwong SM, Ramsay JP, Jensen SO, Firth N. Replication of Staphylococcal Resistance Plasmids. Front Microbiol 2017; 8:2279. [PMID: 29218034 PMCID: PMC5703833 DOI: 10.3389/fmicb.2017.02279] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/06/2017] [Indexed: 11/16/2022] Open
Abstract
The currently widespread and increasing prevalence of resistant bacterial pathogens is a significant medical problem. In clinical strains of staphylococci, the genetic determinants that confer resistance to antimicrobial agents are often located on mobile elements, such as plasmids. Many of these resistance plasmids are capable of horizontal transmission to other bacteria in their surroundings, allowing extraordinarily rapid adaptation of bacterial populations. Once the resistance plasmids have been spread, they are often perpetually maintained in the new host, even in the absence of selective pressure. Plasmid persistence is accomplished by plasmid-encoded genetic systems that ensure efficient replication and segregational stability during cell division. Staphylococcal plasmids utilize proteins of evolutionarily diverse families to initiate replication from the plasmid origin of replication. Several distinctive plasmid copy number control mechanisms have been studied in detail and these appear conserved within plasmid classes. The initiators utilize various strategies and serve a multifunctional role in (i) recognition and processing of the cognate replication origin to an initiation active form and (ii) recruitment of host-encoded replication proteins that facilitate replisome assembly. Understanding the detailed molecular mechanisms that underpin plasmid replication may lead to novel approaches that could be used to reverse or slow the development of resistance.
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Affiliation(s)
- Stephen M Kwong
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Joshua P Ramsay
- School of Biomedical Sciences, Curtin University, Perth, WA, Australia
| | - Slade O Jensen
- Antimicrobial Resistance and Mobile Elements Group, Ingham Institute for Applied Medical Research, Sydney, NSW, Australia
| | - Neville Firth
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
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28
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Ceccarelli D, Garriss G, Choi SY, Hasan NA, Stepanauskas R, Pop M, Huq A, Colwell RR. Characterization of Two Cryptic Plasmids Isolated in Haiti from Clinical Vibrio cholerae Non-O1/Non-O139. Front Microbiol 2017; 8:2283. [PMID: 29218035 PMCID: PMC5703827 DOI: 10.3389/fmicb.2017.02283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/06/2017] [Indexed: 12/14/2022] Open
Abstract
We report the complete sequence of two novel plasmids, pSDH-1 and pSDH-2, isolated from clinical Vibrio cholerae non-O1/non-O139 during the early phase of the 2010 Haitian cholera epidemic. Plasmids were revealed by employing single-cell genomics and their genome content suggests self-mobilization and, for pSDH-2, a toxin-antitoxin (TA) system for plasmid stabilization was identified. The putative origin of replication of pSDH-2 was mapped suggesting it replicates following the ColE1 model of plasmid replication. pSDH-1 and pSDH-2 were widespread among environmental V. cholerae non-O1/non-O139 with variable prevalence in four Haitian Departments. pSDH-2 was the most common element, either alone or with pSDH-1. The two plasmids detection adds to the composite scenario of mobile genetic elements (MGEs) observed in V. cholerae in Haiti. The role these small cryptic plasmids circulating in Vibrio spp. play in bacterial fitness or pathogenicity merits further investigation.
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Affiliation(s)
- Daniela Ceccarelli
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States.,Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, Netherlands
| | - Geneviève Garriss
- Department of Microbiology, Cell Biology and Tumor Biology, Karolinska Institutet, Stockholm, Sweden
| | - Seon Y Choi
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States.,CosmosID Inc., Rockville, MD, United States
| | - Nur A Hasan
- CosmosID Inc., Rockville, MD, United States.,University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, MD, United States
| | | | - Mihai Pop
- University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, MD, United States
| | - Anwar Huq
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States.,Maryland Institute of Applied Environmental Health, University of Maryland, College Park, MD, United States
| | - Rita R Colwell
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States.,CosmosID Inc., Rockville, MD, United States.,University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, MD, United States.,Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
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29
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Characterization of Four Novel Plasmids from Lactobacillus plantarum BM4. Jundishapur J Microbiol 2017. [DOI: 10.5812/jjm.12894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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30
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Lean SS, Yeo CC. Small, Enigmatic Plasmids of the Nosocomial Pathogen, Acinetobacter baumannii: Good, Bad, Who Knows? Front Microbiol 2017; 8:1547. [PMID: 28861061 PMCID: PMC5559437 DOI: 10.3389/fmicb.2017.01547] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/31/2017] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative nosocomial pathogen that has become a serious healthcare concern within a span of two decades due to its ability to rapidly acquire resistance to all classes of antimicrobial compounds. One of the key features of the A. baumannii genome is an open pan genome with a plethora of plasmids, transposons, integrons, and genomic islands, all of which play important roles in the evolution and success of this clinical pathogen, particularly in the acquisition of multidrug resistance determinants. An interesting genetic feature seen in majority of A. baumannii genomes analyzed is the presence of small plasmids that usually ranged from 2 to 10 kb in size, some of which harbor antibiotic resistance genes and homologs of plasmid mobilization genes. These plasmids are often overlooked when compared to their larger, conjugative counterparts that harbor multiple antibiotic resistance genes and transposable elements. In this mini-review, we will examine our current knowledge of these small A. baumannii plasmids and look into their genetic diversity and phylogenetic relationships. Some of these plasmids, such as the Rep-3 superfamily group and the pRAY-type, which has no recognizable replicase genes, are quite widespread among diverse A. baumannii clinical isolates worldwide, hinting at their usefulness to the lifestyle of this pathogen. Other small plasmids especially those from the Rep-1 superfamily are truly enigmatic, encoding only hypothetical proteins of unknown function, leading to the question of whether these small plasmids are “good” or “bad” to their host A. baumannii.
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Affiliation(s)
- Soo Sum Lean
- Saw Swee Hock School of Public Health, National University of SingaporeSingapore, Singapore
| | - Chew Chieng Yeo
- Faculty of Medicine, Biomedical Research Centre, Universiti Sultan Zainal AbidinKuala Terengganu, Malaysia
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31
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Lorenzo-Díaz F, Fernández-López C, Lurz R, Bravo A, Espinosa M. Crosstalk between vertical and horizontal gene transfer: plasmid replication control by a conjugative relaxase. Nucleic Acids Res 2017; 45:7774-7785. [PMID: 28525572 PMCID: PMC5737340 DOI: 10.1093/nar/gkx450] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/25/2017] [Accepted: 05/09/2017] [Indexed: 01/09/2023] Open
Abstract
Horizontal gene transfer is a key process in the evolution of bacteria and also represents a source of genetic variation in eukaryotes. Among elements participating in gene transfer, thousands of small (<10 kb) mobile bacterial plasmids that replicate by the rolling circle mechanism represent a driving force in the spread of antibiotic resistances. In general, these plasmids are built as genetic modules that encode a replicase, an antibiotic-resistance determinant, and a relaxase that participates in their conjugative mobilization. Further, they control their relatively high copy number (∼30 copies per genome equivalent) by antisense RNAs alone or combined with a repressor protein. We report here that the MobM conjugative relaxase encoded by the promiscuous plasmid pMV158 participates in regulation of the plasmid copy number by transcriptional repression of the antisense RNA, thus increasing the number of plasmid molecules ready to be horizontally transferred (mobilization) and/or vertically inherited (replication). This type of crosstalk between genetic modules involved in vertical and horizontal gene flow has not been reported before.
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MESH Headings
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Binding Sites
- Conjugation, Genetic
- DNA Copy Number Variations
- DNA Replication
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- DNA, Bacterial/metabolism
- DNA, Superhelical/chemistry
- DNA, Superhelical/genetics
- DNA, Superhelical/metabolism
- Drug Resistance, Bacterial/genetics
- Endodeoxyribonucleases/genetics
- Endodeoxyribonucleases/metabolism
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Evolution, Molecular
- Gene Flow
- Gene Transfer, Horizontal
- Microscopy, Electron
- Models, Biological
- Plasmids/genetics
- Promoter Regions, Genetic
- Replicon
- Streptococcus pneumoniae/genetics
- Streptococcus pneumoniae/metabolism
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Affiliation(s)
- Fabián Lorenzo-Díaz
- Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Universidad de La Laguna. Av. Astrofísico Francisco Sánchez s/n, 38071 Santa Cruz de Tenerife, Spain
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain
| | - Cris Fernández-López
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Rudi Lurz
- Max-Plank Institut für molekulare Genetik, Ihnestrasse 63-73, D-14195 Berlin, Germany
| | - Alicia Bravo
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain
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32
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Bardaji L, Añorga M, Ruiz-Masó JA, Del Solar G, Murillo J. Plasmid Replicons from Pseudomonas Are Natural Chimeras of Functional, Exchangeable Modules. Front Microbiol 2017; 8:190. [PMID: 28243228 PMCID: PMC5304414 DOI: 10.3389/fmicb.2017.00190] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/25/2017] [Indexed: 01/05/2023] Open
Abstract
Plasmids are a main factor for the evolution of bacteria through horizontal gene exchange, including the dissemination of pathogenicity genes, resistance to antibiotics and degradation of pollutants. Their capacity to duplicate is dependent on their replication determinants (replicon), which also define their bacterial host range and the inability to coexist with related replicons. We characterize a second replicon from the virulence plasmid pPsv48C, from Pseudomonas syringae pv. savastanoi, which appears to be a natural chimera between the gene encoding a newly described replication protein and a putative replication control region present in the widespread family of PFP virulence plasmids. We present extensive evidence of this type of chimerism in structurally similar replicons from species of Pseudomonas, including environmental bacteria as well as plant, animal and human pathogens. We establish that these replicons consist of two functional modules corresponding to putative control (REx-C module) and replication (REx-R module) regions. These modules are functionally separable, do not show specificity for each other, and are dynamically exchanged among replicons of four distinct plasmid families. Only the REx-C module displays strong incompatibility, which is overcome by a few nucleotide changes clustered in a stem-and-loop structure of a putative antisense RNA. Additionally, a REx-C module from pPsv48C conferred replication ability to a non-replicative chromosomal DNA region containing features associated to replicons. Thus, the organization of plasmid replicons as independent and exchangeable functional modules is likely facilitating rapid replicon evolution, fostering their diversification and survival, besides allowing the potential co-option of appropriate genes into novel replicons and the artificial construction of new replicon specificities.
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Affiliation(s)
- Leire Bardaji
- Departamento de Producción Agraria, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Pública de Navarra Pamplona, Spain
| | - Maite Añorga
- Departamento de Producción Agraria, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Pública de Navarra Pamplona, Spain
| | - José A Ruiz-Masó
- Molecular Biology of Gram-Positive Bacteria, Molecular Microbiology and Infection Biology, Centro de Investigaciones Biológicas (Consejo Superior de Investigaciones Científicas) Madrid, Spain
| | - Gloria Del Solar
- Molecular Biology of Gram-Positive Bacteria, Molecular Microbiology and Infection Biology, Centro de Investigaciones Biológicas (Consejo Superior de Investigaciones Científicas) Madrid, Spain
| | - Jesús Murillo
- Departamento de Producción Agraria, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Pública de Navarra Pamplona, Spain
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33
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Grohmann E, Goessweiner-Mohr N, Brantl S. DNA-Binding Proteins Regulating pIP501 Transfer and Replication. Front Mol Biosci 2016; 3:42. [PMID: 27563645 PMCID: PMC4981023 DOI: 10.3389/fmolb.2016.00042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/29/2016] [Indexed: 12/21/2022] Open
Abstract
pIP501 is a Gram-positive broad-host-range model plasmid intensively used for studying plasmid replication and conjugative transfer. It is a multiple antibiotic resistance plasmid frequently detected in clinical Enterococcus faecalis and Enterococcus faecium strains. Replication of pIP501 proceeds unidirectionally by a theta mechanism. The minimal replicon of pIP501 is composed of the repR gene encoding the essential rate-limiting replication initiator protein RepR and the origin of replication, oriR, located downstream of repR. RepR is similar to RepE of related streptococcal plasmid pAMβ1, which has been shown to possess RNase activity cleaving free RNA molecules in close proximity of the initiation site of DNA synthesis. Replication of pIP501 is controlled by the concerted action of a small protein, CopR, and an antisense RNA, RNAIII. CopR has a dual function: It acts as transcriptional repressor at the repR promoter and, in addition, prevents convergent transcription of RNAIII and repR mRNA (RNAII), which indirectly increases RNAIII synthesis. CopR binds asymmetrically as a dimer at two consecutive binding sites upstream of and overlapping with the repR promoter. RNAIII induces transcriptional attenuation within the leader region of the repR mRNA (RNAII). Deletion of either control component causes a 10- to 20-fold increase of plasmid copy number, while simultaneous deletions have no additional effect. Conjugative transfer of pIP501 depends on a type IV secretion system (T4SS) encoded in a single operon. Its transfer host-range is considerably broad, as it has been transferred to virtually all Gram-positive bacteria including Streptomyces and even the Gram-negative Escherichia coli. Expression of the 15 genes encoding the T4SS is tightly controlled by binding of the relaxase TraA, the transfer initiator protein, to the operon promoter overlapping with the origin of transfer (oriT). The T4SS operon encodes the DNA-binding proteins TraJ (VirD4-like coupling protein) and the VirB4-like ATPase, TraE. Both proteins are actively involved in conjugative DNA transport. Moreover, the operon encodes TraN, a small cytoplasmic protein, whose specific binding to a sequence upstream of the oriT nic-site was demonstrated. TraN seems to be an effective repressor of pIP501 transfer, as conjugative transfer rates were significantly increased in an E. faecalis pIP501ΔtraN mutant.
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Affiliation(s)
- Elisabeth Grohmann
- Division of Infectious Diseases, University Medical Center FreiburgFreiburg im Breisgau, Germany; Life Sciences and Technology, Beuth University of Applied Sciences BerlinBerlin, Germany
| | - Nikolaus Goessweiner-Mohr
- Center for Structural System Biology, University Medical Center Hamburg-EppendorfHamburg, Germany; Deutsches Elektronen-SynchrotronHamburg, Germany; Institute of Molecular Biotechnology, Austrian Academy of SciencesVienna, Austria; Research Institute of Molecular PathologyVienna, Austria
| | - Sabine Brantl
- Lehrstuhl für Genetik, Biologisch-Pharmazeutische Fakultät, AG Bakteriengenetik, Friedrich-Schiller-Universität Jena Jena, Germany
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34
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Fröhlich KS, Papenfort K. Interplay of regulatory RNAs and mobile genetic elements in enteric pathogens. Mol Microbiol 2016; 101:701-13. [DOI: 10.1111/mmi.13428] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Kathrin S. Fröhlich
- Department of Biology I, Microbiology; Ludwig-Maximilians-University Munich; 82152 Martinsried Germany
| | - Kai Papenfort
- Department of Biology I, Microbiology; Ludwig-Maximilians-University Munich; 82152 Martinsried Germany
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35
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Abstract
Plasmids are autonomously replicating pieces of DNA. This article discusses theta plasmid replication, which is a class of circular plasmid replication that includes ColE1-like origins of replication popular with expression vectors. All modalities of theta plasmid replication initiate synthesis with the leading strand at a predetermined site and complete replication through recruitment of the host's replisome, which extends the leading strand continuously while synthesizing the lagging strand discontinuously. There are clear differences between different modalities of theta plasmid replication in mechanisms of DNA duplex melting and in priming of leading- and lagging-strand synthesis. In some replicons duplex melting depends on transcription, while other replicons rely on plasmid-encoded trans-acting proteins (Reps); primers for leading-strand synthesis can be generated through processing of a transcript or in other replicons by the action of host- or plasmid-encoded primases. None of these processes require DNA breaks. The frequency of replication initiation is tightly regulated to facilitate establishment in permissive hosts and to achieve a steady state. The last section of the article reviews how plasmid copy number is sensed and how this feedback modulates the frequency of replication.
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36
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Abstract
Plasmids are DNA entities that undergo controlled replication independent of the chromosomal DNA, a crucial step that guarantees the prevalence of the plasmid in its host. DNA replication has to cope with the incapacity of the DNA polymerases to start de novo DNA synthesis, and different replication mechanisms offer diverse solutions to this problem. Rolling-circle replication (RCR) is a mechanism adopted by certain plasmids, among other genetic elements, that represents one of the simplest initiation strategies, that is, the nicking by a replication initiator protein on one parental strand to generate the primer for leading-strand initiation and a single priming site for lagging-strand synthesis. All RCR plasmid genomes consist of a number of basic elements: leading strand initiation and control, lagging strand origin, phenotypic determinants, and mobilization, generally in that order of frequency. RCR has been mainly characterized in Gram-positive bacterial plasmids, although it has also been described in Gram-negative bacterial or archaeal plasmids. Here we aim to provide an overview of the RCR plasmids' lifestyle, with emphasis on their characteristic traits, promiscuity, stability, utility as vectors, etc. While RCR is one of the best-characterized plasmid replication mechanisms, there are still many questions left unanswered, which will be pointed out along the way in this review.
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37
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López-Aguilar C, Romero-López C, Espinosa M, Berzal-Herranz A, Del Solar G. The 5'-tail of antisense RNAII of pMV158 plays a critical role in binding to the target mRNA and in translation inhibition of repB. Front Genet 2015; 6:225. [PMID: 26175752 PMCID: PMC4485353 DOI: 10.3389/fgene.2015.00225] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/12/2015] [Indexed: 02/05/2023] Open
Abstract
Rolling-circle replication of streptococcal plasmid pMV158 is controlled by the concerted action of two trans-acting elements, namely transcriptional repressor CopG and antisense RNAII, which inhibit expression of the repB gene encoding the replication initiator protein. The pMV158-encoded antisense RNAII exerts its activity of replication control by inhibiting translation of the essential repB gene. RNAII is the smallest and simplest among the characterized antisense RNAs involved in control of plasmid replication. Structure analysis of RNAII revealed that it folds into an 8-bp-long stem containing a 1-nt bulge and closed by a 6-nt apical loop. This hairpin is flanked by a 17-nt-long single-stranded 5′-tail and an 8-nt-long 3′-terminal U-rich stretch. Here, the 3′ and 5′ regions of the 5′-tail of RNAII are shown to play a critical role in the binding to the target mRNA and in the inhibition of repB translation, respectively. In contrast, the apical loop of the single hairpin of RNAII plays a rather secondary role and the upper stem region hardly contributes to the binding or inhibition processes. The entire 5′-tail is required for efficient inhibition of repB translation, though only the 8-nt-long region adjacent to the hairpin seems to be essential for rapid binding to the mRNA. These results show that a “kissing” interaction involving base-pairing between complementary hairpin loops in RNAII and mRNA is not critical for efficient RNA/RNA binding or repB translation inhibition. A singular binding mechanism is envisaged whereby initial pairing between complementary single-stranded regions in the antisense and sense RNAs progresses upwards into the corresponding hairpin stems to form the intermolecular duplex.
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Affiliation(s)
- Celeste López-Aguilar
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas (CIB-CSIC) Madrid, Spain
| | - Cristina Romero-López
- Molecular Biology Department, Instituto de Parasitología y Biomedicina López-Neyra (IPBLN-CSIC) Granada, Spain
| | - Manuel Espinosa
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas (CIB-CSIC) Madrid, Spain
| | - Alfredo Berzal-Herranz
- Molecular Biology Department, Instituto de Parasitología y Biomedicina López-Neyra (IPBLN-CSIC) Granada, Spain
| | - Gloria Del Solar
- Molecular Microbiology and Infection Biology Department, Centro de Investigaciones Biológicas (CIB-CSIC) Madrid, Spain
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