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Mikucki A, Kahler CM. Microevolution and Its Impact on Hypervirulence, Antimicrobial Resistance, and Vaccine Escape in Neisseria meningitidis. Microorganisms 2023; 11:3005. [PMID: 38138149 PMCID: PMC10745880 DOI: 10.3390/microorganisms11123005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023] Open
Abstract
Neisseria meningitidis is commensal of the human pharynx and occasionally invades the host, causing the life-threatening illness invasive meningococcal disease. The meningococcus is a highly diverse and adaptable organism thanks to natural competence, a propensity for recombination, and a highly repetitive genome. These mechanisms together result in a high level of antigenic variation to invade diverse human hosts and evade their innate and adaptive immune responses. This review explores the ways in which this diversity contributes to the evolutionary history and population structure of the meningococcus, with a particular focus on microevolution. It examines studies on meningococcal microevolution in the context of within-host evolution and persistent carriage; microevolution in the context of meningococcal outbreaks and epidemics; and the potential of microevolution to contribute to antimicrobial resistance and vaccine escape. A persistent theme is the idea that the process of microevolution contributes to the development of new hyperinvasive meningococcal variants. As such, microevolution in this species has significant potential to drive future public health threats in the form of hypervirulent, antibiotic-resistant, vaccine-escape variants. The implications of this on current vaccination strategies are explored.
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Affiliation(s)
- August Mikucki
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA 6009, Australia;
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia
| | - Charlene M. Kahler
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA 6009, Australia;
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia
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2
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Wang X, Yu D, Chen L. Antimicrobial resistance and mechanisms of epigenetic regulation. Front Cell Infect Microbiol 2023; 13:1199646. [PMID: 37389209 PMCID: PMC10306973 DOI: 10.3389/fcimb.2023.1199646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 05/26/2023] [Indexed: 07/01/2023] Open
Abstract
The rampant use of antibiotics in animal husbandry, farming and clinical disease treatment has led to a significant issue with pathogen resistance worldwide over the past decades. The classical mechanisms of resistance typically investigate antimicrobial resistance resulting from natural resistance, mutation, gene transfer and other processes. However, the emergence and development of bacterial resistance cannot be fully explained from a genetic and biochemical standpoint. Evolution necessitates phenotypic variation, selection, and inheritance. There are indications that epigenetic modifications also play a role in antimicrobial resistance. This review will specifically focus on the effects of DNA modification, histone modification, rRNA methylation and the regulation of non-coding RNAs expression on antimicrobial resistance. In particular, we highlight critical work that how DNA methyltransferases and non-coding RNAs act as transcriptional regulators that allow bacteria to rapidly adapt to environmental changes and control their gene expressions to resist antibiotic stress. Additionally, it will delve into how Nucleolar-associated proteins in bacteria perform histone functions akin to eukaryotes. Epigenetics, a non-classical regulatory mechanism of bacterial resistance, may offer new avenues for antibiotic target selection and the development of novel antibiotics.
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Affiliation(s)
- Xinrui Wang
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- National Health Commission Key Laboratory of Technical Evaluation of Fertility Regulation for Non-Human Primate, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
| | - Donghong Yu
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- National Health Commission Key Laboratory of Technical Evaluation of Fertility Regulation for Non-Human Primate, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
| | - Lu Chen
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- National Health Commission Key Laboratory of Technical Evaluation of Fertility Regulation for Non-Human Primate, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
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3
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Nahar N, Tram G, Jen FEC, Phillips ZN, Weinert L, Bossé J, Jabbari J, Gouil Q, Du MM, Ritchie M, Bowden R, Langford P, Tucker A, Jennings M, Turni C, Blackall P, Atack J. Actinobacillus pleuropneumoniae encodes multiple phase-variable DNA methyltransferases that control distinct phasevarions. Nucleic Acids Res 2023; 51:3240-3260. [PMID: 36840716 PMCID: PMC10123105 DOI: 10.1093/nar/gkad091] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/26/2023] Open
Abstract
Actinobacillus pleuropneumoniae is the cause of porcine pleuropneumonia, a severe respiratory tract infection that is responsible for major economic losses to the swine industry. Many host-adapted bacterial pathogens encode systems known as phasevarions (phase-variable regulons). Phasevarions result from variable expression of cytoplasmic DNA methyltransferases. Variable expression results in genome-wide methylation differences within a bacterial population, leading to altered expression of multiple genes via epigenetic mechanisms. Our examination of a diverse population of A. pleuropneumoniae strains determined that Type I and Type III DNA methyltransferases with the hallmarks of phase variation were present in this species. We demonstrate that phase variation is occurring in these methyltransferases, and show associations between particular Type III methyltransferase alleles and serovar. Using Pacific BioSciences Single-Molecule, Real-Time (SMRT) sequencing and Oxford Nanopore sequencing, we demonstrate the presence of the first ever characterised phase-variable, cytosine-specific Type III DNA methyltransferase. Phase variation of distinct Type III DNA methyltransferase in A. pleuropneumoniae results in the regulation of distinct phasevarions, and in multiple phenotypic differences relevant to pathobiology. Our characterisation of these newly described phasevarions in A. pleuropneumoniae will aid in the selection of stably expressed antigens, and direct and inform development of a rationally designed subunit vaccine against this major veterinary pathogen.
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Affiliation(s)
- Nusrat Nahar
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Freda E-C Jen
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Zachary N Phillips
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Lucy A Weinert
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Janine T Bossé
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Jafar S Jabbari
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Quentin Gouil
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Mei R M Du
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Matthew E Ritchie
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Rory Bowden
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Paul R Langford
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Alexander W Tucker
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Conny Turni
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland 4222, Australia
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4
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Agnew HN, Atack JM, Fernando AR, Waters SN, van der Linden M, Smith E, Abell AD, Brazel EB, Paton JC, Trappetti C. Uncovering the link between the SpnIII restriction modification system and LuxS in Streptococcus pneumoniae meningitis isolates. Front Cell Infect Microbiol 2023; 13:1177857. [PMID: 37197203 PMCID: PMC10184825 DOI: 10.3389/fcimb.2023.1177857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/17/2023] [Indexed: 05/19/2023] Open
Abstract
Streptococcus pneumoniae is capable of randomly switching their genomic DNA methylation pattern between six distinct bacterial subpopulations (A-F) via recombination of a type 1 restriction-modification locus, spnIII. These pneumococcal subpopulations exhibit phenotypic changes which favor carriage or invasive disease. In particular, the spnIIIB allele has been associated with increased nasopharyngeal carriage and the downregulation of the luxS gene. The LuxS/AI-2 QS system represent a universal language for bacteria and has been linked to virulence and biofilm formation in S. pneumoniae. In this work, we have explored the link between spnIII alleles, the luxS gene and virulence in two clinical pneumococcal isolates from the blood and cerebrospinal fluid (CSF) of one pediatric meningitis patient. The blood and CSF strains showed different virulence profiles in mice. Analysis of the spnIII system of these strains recovered from the murine nasopharynx showed that the system switched to different alleles commensurate with the initial source of the isolate. Of note, the blood strain showed high expression of spnIIIB allele, previously linked with less LuxS protein production. Importantly, strains with deleted luxS displayed different phenotypic profiles compared to the wildtype, but similar to the strains recovered from the nasopharynx of infected mice. This study used clinically relevant S. pneumoniae strains to demonstrate that the regulatory network between luxS and the type 1 restriction-modification system play a key role in infections and may support different adaptation to specific host niches.
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Affiliation(s)
- Hannah N. Agnew
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - John M. Atack
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
- School of Environment and Science, Griffith University, Gold Coast, QLD, Australia
| | - Ann R.D. Fernando
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - Sophie N. Waters
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - Mark van der Linden
- German National Reference Center for Streptococci, University Hospital Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Aachen, Germany
| | - Erin Smith
- School of Physical Sciences, Faculty of Sciences, Engineering and Technology, University of Adelaide, Adelaide, SA, Australia
| | - Andrew D. Abell
- School of Physical Sciences, Faculty of Sciences, Engineering and Technology, University of Adelaide, Adelaide, SA, Australia
| | - Erin B. Brazel
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - James C. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
- *Correspondence: Claudia Trappetti, ; James C. Paton,
| | - Claudia Trappetti
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
- *Correspondence: Claudia Trappetti, ; James C. Paton,
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5
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Li RJ, Qin C, Huang GR, Liao LJ, Mo XQ, Huang YQ. Phillygenin Inhibits Helicobacter pylori by Preventing Biofilm Formation and Inducing ATP Leakage. Front Microbiol 2022; 13:863624. [PMID: 35572695 PMCID: PMC9097866 DOI: 10.3389/fmicb.2022.863624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/10/2022] [Indexed: 11/13/2022] Open
Abstract
With the widespread use and abuse of antibiotics, Helicobacter pylori (H. pylori) has become seriously drug resistant. The development of new antibiotics is an important way to solve H. pylori's drug resistance. Screening antibacterial ingredients from natural products is a convenient way to develop new antibiotics. Phillygenin, an effective antibacterial component, was selected from the natural product, forsythia, in this study. Its minimal inhibitory concentration (MIC) for 18 H. pylori strains was 16-32 μg/ml. The minimum bactericidal concentration (MBC) of H. pylori G27 was 128 μg/ml; the higher the drug concentration and the longer the time, the better the sterilization effect. It was non-toxic to gastric epithelial cell (GES)-1 and BGC823 cells at the concentration of 100 μg/ml. It presented a better antibacterial effect on H. pylori in an acidic environment, and after 24 days of induction on H. pylori with 1/4 MIC of phillygenin, no change was found in the MIC of H. pylori. In the mechanism of action, phillygenin could cause ATP leakage and inhibit the biofilm formation; the latter was associated with the regulation of spoT and Hp1174 genes. In addition, phillygenin could regulate the genes of Nhac, caggamma, MATE, MdoB, flagellinA, and lptB, leading to the weakening of H. pylori's acid resistance and virulence, the diminishing of H. pylori's capacity for drug efflux, H. pylori's DNA methylation, the initiation of human immune response, and the ATP leakage of H. pylori, thus accelerating the death of H. pylori. In conclusion, phillygenin was a main ingredient inhibiting H. pylori in Forsythia suspensa, with a good antibacterial activity, high safety, strong specificity, better antibacterial effect under acidic conditions, and low risk of resistance development by H. pylori. Its mechanism of action was mainly associated with inhibiting the biofilm formation and resulting in ATP leakage. In addition, phillygenin was shown to be able to reduce the acid resistance and virulence of H. pylori.
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Affiliation(s)
- Ru-Jia Li
- Research Center for the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise, China
| | - Chun Qin
- Research Center for the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise, China
| | - Gan-Rong Huang
- Research Center for the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise, China
| | - Li-Juan Liao
- Research Center for the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise, China
| | - Xiao-Qiang Mo
- Research Center for the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise, China
| | - Yan-Qiang Huang
- Research Center for the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise, China
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6
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Abstract
The noncanonical structures, G-quadruplexes (GQs), formed in the guanine-rich region of nucleic acids regulate various biological and molecular functions in prokaryotes and eukaryotes. Neisseria meningitidis is a commensal residing in a human's upper respiratory tract but occasionally becomes virulent, causing life-threatening septicemia and meningitis. The factors causing these changes in phenotypes are not fully understood. At the molecular level, regulatory components help in a clearer understanding of the pathogen's virulence and pathogenesis. Herein, genome analysis followed by biophysical assays and cell-based experiments revealed the presence of conserved GQ motifs in N. meningitidis. These GQs are linked to the essential genes involved in cell adhesion, pathogenesis, virulence, transport, DNA repair, and recombination. Primer extension stop assay, reporter assays, and quantitative real-time polymerase chain reaction (qRT-PCR) further affirmed the formation of stable GQs in vitro and in vivo. These results support the existence of evolutionarily conserved GQ motifs in N. meningitidis and uphold the usage of GQ-specific ligands as novel antimeningococcal therapeutics.
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Characterization of the Type I Restriction Modification System Broadly Conserved among Group A Streptococci. mSphere 2021; 6:e0079921. [PMID: 34787444 PMCID: PMC8597746 DOI: 10.1128/msphere.00799-21] [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] [Indexed: 11/20/2022] Open
Abstract
Although prokaryotic DNA methylation investigations have long focused on immunity against exogenous DNA, it has been recently recognized that DNA methylation impacts gene expression and phase variation in Streptococcus pneumoniae and Streptococcus suis. A comprehensive analysis of DNA methylation is lacking for beta-hemolytic streptococci, and thus we sought to examine DNA methylation in the major human pathogen group A Streptococcus (GAS). Using a database of 224 GAS genomes encompassing 80 emm types, we found that nearly all GAS strains encode a type I restriction modification (RM) system that lacks the hsdS′ alleles responsible for impacting gene expression in S. pneumoniae and S. suis. The GAS type I system is located on the core chromosome, while sporadically present type II orphan methyltransferases were identified on prophages. By combining single-molecule real-time (SMRT) analyses of 10 distinct emm types along with phylogenomics of 224 strains, we were able to assign 13 methylation patterns to the GAS population. Inactivation of the type I RM system, occurring either naturally through phage insertion or through laboratory-induced gene deletion, abrogated DNA methylation detectable via either SMRT or MinION sequencing. Contrary to a previous report, inactivation of the type I system did not impact transcript levels of the gene (mga) encoding the key multigene activator protein (Mga) or Mga-regulated genes. Inactivation of the type I system significantly increased plasmid transformation rates. These data delineate the breadth of the core chromosomal type I RM system in the GAS population and clarify its role in immunity rather than impacting Mga regulon expression. IMPORTANCE The advent of whole-genome approaches capable of detecting DNA methylation has markedly expanded appreciation of the diverse roles of epigenetic modification in prokaryotic physiology. For example, recent studies have suggested that DNA methylation impacts gene expression in some streptococci. The data described herein are from the first systematic analysis of DNA methylation in a beta-hemolytic streptococcus and one of the few analyses to comprehensively characterize DNA methylation across hundreds of strains of the same bacterial species. We clarify that DNA methylation in group A Streptococcus (GAS) is primarily due to a type I restriction modification (RM) system present in the core genome and does not impact mga-regulated virulence gene expression, but does impact immunity against exogenous DNA. The identification of the DNA motifs recognized by each type I RM system may assist with optimizing methods for GAS genetic manipulation and help us understand how bacterial pathogens acquire exogenous DNA elements.
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Mehershahi KS, Chen SL. DNA methylation by three Type I restriction modification systems of Escherichia coli does not influence gene regulation of the host bacterium. Nucleic Acids Res 2021; 49:7375-7388. [PMID: 34181709 PMCID: PMC8287963 DOI: 10.1093/nar/gkab530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/01/2021] [Accepted: 06/22/2021] [Indexed: 12/13/2022] Open
Abstract
DNA methylation is a common epigenetic mark that influences transcriptional regulation, and therefore cellular phenotype, across all domains of life. In particular, both orphan methyltransferases and those from phasevariable restriction modification systems (RMSs) have been co-opted to regulate virulence epigenetically in many bacteria. We now show that three distinct non-phasevariable Type I RMSs in Escherichia coli have no measurable impact on gene expression, in vivo virulence, or any of 1190 in vitro growth phenotypes. We demonstrated this using both Type I RMS knockout mutants as well as heterologous installation of Type I RMSs into two E. coli strains. These data provide three clear and currently rare examples of restriction modification systems that have no impact on their host organism’s gene regulation. This leads to the possibility that other such nonregulatory methylation systems may exist, broadening our view of the potential role that RMSs may play in bacterial evolution.
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Affiliation(s)
- Kurosh S Mehershahi
- NUHS Infectious Diseases Translational Research Programme, Department of Medicine, Division of Infectious Diseases, Yong Loo Lin School of Medicine, Singapore 119228
| | - Swaine L Chen
- NUHS Infectious Diseases Translational Research Programme, Department of Medicine, Division of Infectious Diseases, Yong Loo Lin School of Medicine, Singapore 119228.,Laboratory of Bacterial Genomics, Genome Institute of Singapore, Singapore 138672
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9
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Anton BP, Roberts RJ. Beyond Restriction Modification: Epigenomic Roles of DNA Methylation in Prokaryotes. Annu Rev Microbiol 2021; 75:129-149. [PMID: 34314594 DOI: 10.1146/annurev-micro-040521-035040] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The amount of bacterial and archaeal genome sequence and methylome data has greatly increased over the last decade, enabling new insights into the functional roles of DNA methylation in these organisms. Methyltransferases (MTases), the enzymes responsible for DNA methylation, are exchanged between prokaryotes through horizontal gene transfer and can function either as part of restriction-modification systems or in apparent isolation as single (orphan) genes. The patterns of DNA methylation they confer on the host chromosome can have significant effects on gene expression, DNA replication, and other cellular processes. Some processes require very stable patterns of methylation, resulting in conservation of persistent MTases in a particular lineage. Other processes require patterns that are more dynamic yet more predictable than what is afforded by horizontal gene transfer and gene loss, resulting in phase-variable or recombination-driven MTase alleles. In this review, we discuss what is currently known about the functions of DNA methylation in prokaryotes in light of these evolutionary patterns. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Brian P Anton
- New England Biolabs, Ipswich, Massachusetts 01938, USA; ,
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10
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Genome-wide methylome analysis of two strains belonging to the hypervirulent Neisseria meningitidis serogroup W ST-11 clonal complex. Sci Rep 2021; 11:6239. [PMID: 33737546 PMCID: PMC7973814 DOI: 10.1038/s41598-021-85266-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 02/26/2021] [Indexed: 11/08/2022] Open
Abstract
A rising incidence of meningococcal serogroup W disease has been evident in many countries worldwide. Serogroup W isolates belonging to the sequence type (ST)-11 clonal complex have been associated with atypical symptoms and increased case fatality rates. The continued expansion of this clonal complex in the later part of the 2010s has been largely due to a shift from the so-called original UK strain to the 2013 strain. Here we used single-molecule real-time (SMRT) sequencing to determine the methylomes of the two major serogroup W strains belonging to ST-11 clonal complex. Five methylated motifs were identified in this study, and three of the motifs, namely 5'-GATC-3', 5'-GAAGG-3', 5'-GCGCGC-3', were found in all 13 isolates investigated. The results showed no strain-specific motifs or difference in active restriction modification systems between the two strains. Two phase variable methylases were identified and the enrichment or depletion of the methylation motifs generated by these methylases varied between the two strains. Results from this work give further insight into the low diversity of methylomes in highly related strains and encourage further research to decipher the role of regions with under- or overrepresented methylation motifs.
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11
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Mustapha MM, Marsh JW, Shutt KA, Schlackman J, Ezeonwuka C, Farley MM, Stephens DS, Wang X, Van Tyne D, Harrison LH. Transmission Dynamics and Microevolution of Neisseria meningitidis During Carriage and Invasive Disease in High School Students in Georgia and Maryland, 2006-2007. J Infect Dis 2020; 223:2038-2047. [PMID: 33107578 DOI: 10.1093/infdis/jiaa674] [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: 05/08/2020] [Accepted: 10/21/2020] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The mechanisms by which Neisseria meningitidis cause persistent human carriage and transition from carriage to invasive disease have not been fully elucidated. METHODS Georgia and Maryland high school students were sampled for pharyngeal carriage of N. meningitidis during the 2006-2007 school year. A total of 321 isolates from 188 carriers and all 67 invasive disease isolates collected during the same time and from the same geographic region underwent whole-genome sequencing. Core-genome multilocus sequence typing was used to compare allelic profiles, and direct read mapping was used to study strain evolution. RESULTS Among 188 N. meningitidis culture-positive students, 98 (52.1%) were N. meningitidis culture positive at 2 or 3 samplings. Most students who were positive at >1 sampling (98%) had persistence of a single strain. More than a third of students carried isolates that were highly genetically related to isolates from other students in the same school, and occasional transmission within the same county was also evident. The major pilin subunit gene, pilE, was the most variable gene, and no carrier had identical pilE sequences at different time points. CONCLUSION We found strong evidence of local meningococcal transmission at both the school and county levels. Allelic variation within genes encoding bacterial surface structures, particularly pilE, was common.
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Affiliation(s)
- Mustapha M Mustapha
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jane W Marsh
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Kathleen A Shutt
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jessica Schlackman
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chinelo Ezeonwuka
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Monica M Farley
- Emory University Department of Medicine, Atlanta, Georgia, USA.,Atlanta VA Medical Center, Atlanta, Georgia, USA
| | | | - Xin Wang
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Daria Van Tyne
- Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Lee H Harrison
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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12
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Seib KL, Srikhanta YN, Atack JM, Jennings MP. Epigenetic Regulation of Virulence and Immunoevasion by Phase-Variable Restriction-Modification Systems in Bacterial Pathogens. Annu Rev Microbiol 2020; 74:655-671. [PMID: 32689914 DOI: 10.1146/annurev-micro-090817-062346] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human-adapted bacterial pathogens use a mechanism called phase variation to randomly switch the expression of individual genes to generate a phenotypically diverse population to adapt to challenges within and between human hosts. There are increasing reports of restriction-modification systems that exhibit phase-variable expression. The outcome of phase variation of these systems is global changes in DNA methylation. Analysis of phase-variable Type I and Type III restriction-modification systems in multiple human-adapted bacterial pathogens has demonstrated that global changes in methylation regulate the expression of multiple genes. These systems are called phasevarions (phase-variable regulons). Phasevarion switching alters virulence phenotypes and facilitates evasion of host immune responses. This review describes the characteristics of phasevarions and implications for pathogenesis and immune evasion. We present and discuss examples of phasevarion systems in the major human pathogens Haemophilus influenzae, Neisseria meningitidis, Neisseria gonorrhoeae, Helicobacter pylori, Moraxella catarrhalis, and Streptococcus pneumoniae.
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Affiliation(s)
- Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia; ,
| | - Yogitha N Srikhanta
- Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia; ,
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia; ,
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13
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Wanford JJ, Holmes JC, Bayliss CD, Green LR. Meningococcal core and accessory phasomes vary by clonal complex. Microb Genom 2020; 6:e000367. [PMID: 32375989 PMCID: PMC7371114 DOI: 10.1099/mgen.0.000367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/27/2020] [Indexed: 11/21/2022] Open
Abstract
Neisseria meningitidis is a Gram-negative human commensal pathogen, with extensive phenotypic plasticity afforded by phase-variable (PV) gene expression. Phase variation is a stochastic switch in gene expression from an ON to an OFF state, mediated by localized hypermutation of simple sequence repeats (SSRs). Circulating N. meningitidis clones vary in propensity to cause disease, with some clonal complexes (ccs) classified as hypervirulent and others as carriage-associated. We examined the PV gene repertoires, or phasome, of these lineages in order to determine whether phase variation contributes to disease propensity. We analysed 3328 genomes representative of nine circulating meningococcal ccs with PhasomeIt, a tool that identifies PV genes by the presence of SSRs and homologous gene clusters. The presence, absence and functions of all identified PV gene clusters were confirmed by annotation or blast searches within the Neisseria PubMLST database. While no significant differences were detected in the number of PV genes or the core, conserved phasome content between hypervirulent and carriage lineages, individual ccs exhibited major variations in PV gene numbers. Phylogenetic clusters produced by phasome or core genome analyses were similar, indicating co-evolution of PV genes with the core genome. While conservation of PV clusters is high, with 76 % present in all meningococcal isolates, maintenance of an SSR is variable, ranging from conserved in all isolates to present only in a single cc, indicating differing evolutionary trajectories for each lineage. Diverse functional groups of PV genes were present across the meningococcal lineages; however, the majority directly or indirectly influence bacterial surface antigens and could impact on future vaccine development. Finally, we observe that meningococci have open pan phasomes, indicating ongoing evolution of PV gene content and a significant potential for adaptive changes in this clinically relevant genus.
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Affiliation(s)
- Joseph J. Wanford
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Jonathan C. Holmes
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | | | - Luke R. Green
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
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14
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Stenmark B, Harrison OB, Eriksson L, Anton BP, Fomenkov A, Roberts RJ, Tooming-Klunderud A, Bratcher HB, Bray JE, Thulin-Hedberg S, Maiden MCJ, Mölling P. Complete genome and methylome analysis of Neisseria meningitidis associated with increased serogroup Y disease. Sci Rep 2020; 10:3644. [PMID: 32108139 PMCID: PMC7046676 DOI: 10.1038/s41598-020-59509-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/22/2020] [Indexed: 12/22/2022] Open
Abstract
Invasive meningococcal disease (IMD) due to serogroup Y Neisseria meningitidis emerged in Europe during the 2000s. Draft genomes of serogroup Y isolates in Sweden revealed that although the population structure of these isolates was similar to other serogroup Y isolates internationally, a distinct strain (YI) and more specifically a sublineage (1) of this strain was responsible for the increase of serogroup Y IMD in Sweden. We performed single molecule real-time (SMRT) sequencing on eight serogroup Y isolates from different sublineages to unravel the genetic and epigenetic factors delineating them, in order to understand the serogroup Y emergence. Extensive comparisons between the serogroup Y sublineages of all coding sequences, complex genomic regions, intergenic regions, and methylation motifs revealed small point mutations in genes mainly encoding hypothetical and metabolic proteins, and non-synonymous variants in genes involved in adhesion, iron acquisition, and endotoxin production. The methylation motif CACNNNNNTAC was only found in isolates of sublineage 2. Only seven genes were putatively differentially expressed, and another two genes encoding hypothetical proteins were only present in sublineage 2. These data suggest that the serogroup Y IMD increase in Sweden was most probably due to small changes in genes important for colonization and transmission.
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Affiliation(s)
- Bianca Stenmark
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
| | - Odile B Harrison
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Lorraine Eriksson
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | | | | | | | - Ave Tooming-Klunderud
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Holly B Bratcher
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - James E Bray
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Sara Thulin-Hedberg
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | | | - Paula Mölling
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
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15
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Caugant DA, Brynildsrud OB. Neisseria meningitidis: using genomics to understand diversity, evolution and pathogenesis. Nat Rev Microbiol 2019; 18:84-96. [PMID: 31705134 DOI: 10.1038/s41579-019-0282-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2019] [Indexed: 01/30/2023]
Abstract
Meningococcal disease remains an important cause of morbidity and death worldwide despite the development and increasing implementation of effective vaccines. Elimination of the disease is hampered by the enormous diversity and antigenic variability of the causative agent, Neisseria meningitidis, one of the most variable bacteria in nature. These features are attained mainly through high rates of horizontal gene transfer and alteration of protein expression through phase variation. The recent availability of whole-genome sequencing (WGS) of large-scale collections of N. meningitidis isolates from various origins, databases to facilitate storage and sharing of WGS data and the concomitant development of effective bioinformatics tools have led to a much more thorough understanding of the diversity of the species, its evolution and population structure and how virulent traits may emerge. Implementation of WGS is already contributing to enhanced epidemiological surveillance and is essential to ascertain the impact of vaccination strategies. This Review summarizes the recent advances provided by WGS studies in our understanding of the biology of N. meningitidis and the epidemiology of meningococcal disease.
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Affiliation(s)
- Dominique A Caugant
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway. .,Department of Community Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Ola B Brynildsrud
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.,Department of Food Safety and Infection Biology, Faculty of Veterinary Science, Norwegian University of Life Science, Oslo, Norway
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16
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Sánchez-Busó L, Golparian D, Parkhill J, Unemo M, Harris SR. Genetic variation regulates the activation and specificity of Restriction-Modification systems in Neisseria gonorrhoeae. Sci Rep 2019; 9:14685. [PMID: 31605008 PMCID: PMC6789123 DOI: 10.1038/s41598-019-51102-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 09/25/2019] [Indexed: 01/14/2023] Open
Abstract
Restriction-Modification systems (RMS) are one of the main mechanisms of defence against foreign DNA invasion and can have an important role in the regulation of gene expression. The obligate human pathogen Neisseria gonorrhoeae carries one of the highest loads of RMS in its genome; between 13 to 15 of the three main types. Previous work has described their organization in the reference genome FA1090 and has inferred the associated methylated motifs. Here, we studied the structure of RMS and target methylated motifs in 25 gonococcal strains sequenced with Single Molecule Real-Time (SMRT) technology, which provides data on DNA modification. The results showed a variable picture of active RMS in different strains, with phase variation switching the activity of Type III RMS, and both the activity and specificity of a Type I RMS. Interestingly, the Dam methylase was found in place of the NgoAXI endonuclease in two of the strains, despite being previously thought to be absent in the gonococcus. We also identified the real methylation target of NgoAXII as 5′-GCAGA-3′, different from that previously described. Results from this work give further insights into the diversity and dynamics of RMS and methylation patterns in N. gonorrhoeae.
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Affiliation(s)
- Leonor Sánchez-Busó
- Centre for Genomic Pathogen Surveillance, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK. .,Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Daniel Golparian
- WHO Collaborating Centre for Gonorrhoea and other Sexually Transmitted Infections, National Reference Laboratory for Sexually Transmitted Infections, Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Magnus Unemo
- WHO Collaborating Centre for Gonorrhoea and other Sexually Transmitted Infections, National Reference Laboratory for Sexually Transmitted Infections, Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Simon R Harris
- Microbiotica Ltd, Biodata Innovation Centre, Wellcome Genome Campus, Hinxton, Cambridge, UK.
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17
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Phase-variable bacterial loci: how bacteria gamble to maximise fitness in changing environments. Biochem Soc Trans 2019; 47:1131-1141. [PMID: 31341035 DOI: 10.1042/bst20180633] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/02/2019] [Accepted: 07/05/2019] [Indexed: 12/19/2022]
Abstract
Phase-variation of genes is defined as the rapid and reversible switching of expression - either ON-OFF switching or the expression of multiple allelic variants. Switching of expression can be achieved by a number of different mechanisms. Phase-variable genes typically encode bacterial surface structures, such as adhesins, pili, and lipooligosaccharide, and provide an extra contingency strategy in small-genome pathogens that may lack the plethora of 'sense-and-respond' gene regulation systems found in other organisms. Many bacterial pathogens also encode phase-variable DNA methyltransferases that control the expression of multiple genes in systems called phasevarions (phase-variable regulons). The presence of phase-variable genes allows a population of bacteria to generate a number of phenotypic variants, some of which may be better suited to either colonising certain host niches, surviving a particular environmental condition and/or evading an immune response. The presence of phase-variable genes complicates the determination of an organism's stably expressed antigenic repertoire; many phase-variable genes are highly immunogenic, and so would be ideal vaccine candidates, but unstable expression due to phase-variation may allow vaccine escape. This review will summarise our current understanding of phase-variable genes that switch expression by a variety of mechanisms, and describe their role in disease and pathobiology.
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18
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Atack JM, Yang Y, Seib KL, Zhou Y, Jennings MP. A survey of Type III restriction-modification systems reveals numerous, novel epigenetic regulators controlling phase-variable regulons; phasevarions. Nucleic Acids Res 2019; 46:3532-3542. [PMID: 29554328 PMCID: PMC5909438 DOI: 10.1093/nar/gky192] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/10/2018] [Indexed: 12/21/2022] Open
Abstract
Many bacteria utilize simple DNA sequence repeats as a mechanism to randomly switch genes on and off. This process is called phase variation. Several phase-variable N6-adenine DNA-methyltransferases from Type III restriction-modification systems have been reported in bacterial pathogens. Random switching of DNA methyltransferases changes the global DNA methylation pattern, leading to changes in gene expression. These epigenetic regulatory systems are called phasevarions — phase-variable regulons. The extent of these phase-variable genes in the bacterial kingdom is unknown. Here, we interrogated a database of restriction-modification systems, REBASE, by searching for all simple DNA sequence repeats in mod genes that encode Type III N6-adenine DNA-methyltransferases. We report that 17.4% of Type III mod genes (662/3805) contain simple sequence repeats. Of these, only one-fifth have been previously identified. The newly discovered examples are widely distributed and include many examples in opportunistic pathogens as well as in environmental species. In many cases, multiple phasevarions exist in one genome, with examples of up to 4 independent phasevarions in some species. We found several new types of phase-variable mod genes, including the first example of a phase-variable methyltransferase in pathogenic Escherichia coli. Phasevarions are a common epigenetic regulation contingency strategy used by both pathogenic and non-pathogenic bacteria.
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Affiliation(s)
- John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Yuedong Yang
- School of Data and Computer Science, Sun Yat-Sen University, Guangzhou 510006, China
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Yaoqi Zhou
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
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19
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Phillips ZN, Husna AU, Jennings MP, Seib KL, Atack JM. Phasevarions of bacterial pathogens - phase-variable epigenetic regulators evolving from restriction-modification systems. MICROBIOLOGY-SGM 2019; 165:917-928. [PMID: 30994440 DOI: 10.1099/mic.0.000805] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Phase-variable DNA methyltransferases control the expression of multiple genes via epigenetic mechanisms in a wide variety of bacterial species. These systems are called phasevarions, for phase-variable regulons. Phasevarions regulate genes involved in pathogenesis, host adaptation and antibiotic resistance. Many human-adapted bacterial pathogens contain phasevarions. These include leading causes of morbidity and mortality worldwide, such as non-typeable Haemophilus influenzae, Streptococcus pneumoniae and Neisseria spp. Phase-variable methyltransferases and phasevarions have also been discovered in environmental organisms and veterinary pathogens. The existence of many different examples suggests that phasevarions have evolved multiple times as a contingency strategy in the bacterial domain, controlling phenotypes that are important in adapting to environmental change. Many of the organisms that contain phasevarions have existing or emerging drug resistance. Vaccines may therefore represent the best and most cost-effective tool to prevent disease caused by these organisms. However, many phasevarions also control the expression of current and putative vaccine candidates; variable expression of antigens could lead to immune evasion, meaning that vaccines designed using these targets become ineffective. It is therefore essential to characterize phasevarions in order to determine an organism's stably expressed antigenic repertoire, and rationally design broadly effective vaccines.
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Affiliation(s)
- Zachary N Phillips
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Asma-Ul Husna
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
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20
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Atack JM, Weinert LA, Tucker AW, Husna AU, Wileman TM, F. Hadjirin N, Hoa NT, Parkhill J, Maskell DJ, Blackall PJ, Jennings MP. Streptococcus suis contains multiple phase-variable methyltransferases that show a discrete lineage distribution. Nucleic Acids Res 2018; 46:11466-11476. [PMID: 30304532 PMCID: PMC6265453 DOI: 10.1093/nar/gky913] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/20/2018] [Accepted: 10/06/2018] [Indexed: 12/22/2022] Open
Abstract
Streptococcus suis is a major pathogen of swine, responsible for a number of chronic and acute infections, and is also emerging as a major zoonotic pathogen, particularly in South-East Asia. Our study of a diverse population of S. suis shows that this organism contains both Type I and Type III phase-variable methyltransferases. In all previous examples, phase-variation of methyltransferases results in genome wide methylation differences, and results in differential regulation of multiple genes, a system known as the phasevarion (phase-variable regulon). We hypothesized that each variant in the Type I and Type III systems encoded a methyltransferase with a unique specificity, and could therefore control a distinct phasevarion, either by recombination-driven shuffling between different specificities (Type I) or by biphasic on-off switching via simple sequence repeats (Type III). Here, we present the identification of the target specificities for each Type III allelic variant from S. suis using single-molecule, real-time methylome analysis. We demonstrate phase-variation is occurring in both Type I and Type III methyltransferases, and show a distinct association between methyltransferase type and presence, and population clades. In addition, we show that the phase-variable Type I methyltransferase was likely acquired at the origin of a highly virulent zoonotic sub-population.
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Affiliation(s)
- John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Lucy A Weinert
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Alexander W Tucker
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Asma U Husna
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Thomas M Wileman
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Nazreen F. Hadjirin
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Ngo T Hoa
- Oxford University Clinical Research Unit (OUCRU), 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Viet Nam, and Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
| | | | - Duncan J Maskell
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
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21
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Blakeway LV, Tan A, Lappan R, Ariff A, Pickering JL, Peacock CS, Blyth CC, Kahler CM, Chang BJ, Lehmann D, Kirkham LAS, Murphy TF, Jennings MP, Bakaletz LO, Atack JM, Peak IR, Seib KL. Moraxella catarrhalis Restriction-Modification Systems Are Associated with Phylogenetic Lineage and Disease. Genome Biol Evol 2018; 10:2932-2946. [PMID: 30335144 PMCID: PMC6241649 DOI: 10.1093/gbe/evy226] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2018] [Indexed: 01/25/2023] Open
Abstract
Moraxella catarrhalis is a human-adapted pathogen, and a major cause of otitis media (OM) and exacerbations of chronic obstructive pulmonary disease. The species is comprised of two main phylogenetic lineages, RB1 and RB2/3. Restriction–modification (R-M) systems are among the few lineage-associated genes identified in other bacterial genera and have multiple functions including defense against foreign invading DNA, maintenance of speciation, and epigenetic regulation of gene expression. Here, we define the repertoire of R-M systems in 51 publicly available M. catarrhalis genomes and report their distribution among M. catarrhalis phylogenetic lineages. An association with phylogenetic lineage (RB1 or RB2/3) was observed for six R-M systems, which may contribute to the evolution of the lineages by restricting DNA transformation. In addition, we observed a relationship between a mutually exclusive Type I R-M system and a Type III R-M system at a single locus conserved throughout a geographically and clinically diverse set of M. catarrhalis isolates. The Type III R-M system at this locus contains the phase-variable Type III DNA methyltransferase, modM, which controls a phasevarion (phase-variable regulon). We observed an association between modM presence and OM-associated middle ear isolates, indicating a potential role for ModM-mediated epigenetic regulation in OM pathobiology.
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Affiliation(s)
- Luke V Blakeway
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Aimee Tan
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Rachael Lappan
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Amir Ariff
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Janessa L Pickering
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.,School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Christopher S Peacock
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Christopher C Blyth
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.,School of Medicine, The University of Western Australia, Perth, Western Australia, Australia.,Department of Infectious Diseases, Perth Chilren's Hospital, Perth, Western Australia, Australia.,Department of Microbiology, PathWest Laboratory Medicine, QEII Medical Centre, Perth, Western Australia, Australia
| | - Charlene M Kahler
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Barbara J Chang
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Deborah Lehmann
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Lea-Ann S Kirkham
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.,School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Timothy F Murphy
- Clinical and Translational Research Center, University at Buffalo, the State University of New York, Buffalo, New York, USA
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Ian R Peak
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.,School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
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22
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Parise D, Parise MTD, Viana MVC, Muñoz-Bucio AV, Cortés-Pérez YA, Arellano-Reynoso B, Díaz-Aparicio E, Dorella FA, Pereira FL, Carvalho AF, Figueiredo HCP, Ghosh P, Barh D, Gomide ACP, Azevedo VAC. First genome sequencing and comparative analyses of Corynebacterium pseudotuberculosis strains from Mexico. Stand Genomic Sci 2018; 13:21. [PMID: 30338024 PMCID: PMC6180578 DOI: 10.1186/s40793-018-0325-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 09/24/2018] [Indexed: 12/20/2022] Open
Abstract
Corynebacterium pseudotuberculosis is a pathogenic bacterium which has been rapidly spreading all over the world, causing economic losses in the agricultural sector and sporadically infecting humans. Six C. pseudotuberculosis strains were isolated from goats, sheep, and horses with distinct abscess locations. For the first time, Mexican genomes of this bacterium were sequenced and studied in silico. All strains were sequenced using Ion Personal Genome Machine sequencer, assembled using Newbler and SPAdes software. The automatic genome annotation was done using the software RAST and in-house scripts for transference, followed by manual curation using Artemis software and BLAST against NCBI and UniProt databases. The six genomes are publicly available in NCBI database. The analysis of nucleotide sequence similarity and the generated phylogenetic tree led to the observation that the Mexican strains are more similar between strains from the same host, but the genetic structure is probably more influenced by transportation of animals between farms than host preference. Also, a putative drug target was predicted and in silico analysis of 46 strains showed two gene clusters capable of differentiating the biovars equi and ovis: Restriction Modification system and CRISPR-Cas cluster.
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Affiliation(s)
- Doglas Parise
- Laboratory of Cellular and Molecular Genetics, Institute of Biologic Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Mariana T D Parise
- Laboratory of Cellular and Molecular Genetics, Institute of Biologic Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Marcus V C Viana
- Laboratory of Cellular and Molecular Genetics, Institute of Biologic Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Adrian V Muñoz-Bucio
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Mexico City, Mexico
| | - Yazmin A Cortés-Pérez
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Mexico City, Mexico
| | - Beatriz Arellano-Reynoso
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Mexico City, Mexico
| | - Efrén Díaz-Aparicio
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Mexico City, Mexico
| | - Fernanda A Dorella
- Aquacen - National Reference Laboratory for Aquatic Animal Diseases, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Felipe L Pereira
- Aquacen - National Reference Laboratory for Aquatic Animal Diseases, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Alex F Carvalho
- Aquacen - National Reference Laboratory for Aquatic Animal Diseases, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Henrique C P Figueiredo
- Aquacen - National Reference Laboratory for Aquatic Animal Diseases, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA-23284 USA
| | - Debmalya Barh
- Laboratory of Cellular and Molecular Genetics, Institute of Biologic Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology (IIOAB), Nonakuri, Purba Medinipur, West Bengal 721172 India
- Division of Bioinformatics and Computational Genomics, NITTE University Center for Science Education and Research (NUCSER), NITTE (Deemed to be University), Deralakatte, Mangaluru, Karnataka India
| | - Anne C P Gomide
- Laboratory of Cellular and Molecular Genetics, Institute of Biologic Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Vasco A C Azevedo
- Laboratory of Cellular and Molecular Genetics, Institute of Biologic Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
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23
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Atack JM, Tan A, Bakaletz LO, Jennings MP, Seib KL. Phasevarions of Bacterial Pathogens: Methylomics Sheds New Light on Old Enemies. Trends Microbiol 2018; 26:715-726. [PMID: 29452952 PMCID: PMC6054543 DOI: 10.1016/j.tim.2018.01.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 01/06/2018] [Accepted: 01/26/2018] [Indexed: 01/04/2023]
Abstract
A wide variety of bacterial pathogens express phase-variable DNA methyltransferases that control expression of multiple genes via epigenetic mechanisms. These randomly switching regulons - phasevarions - regulate genes involved in pathogenesis, host adaptation, and antibiotic resistance. Individual phase-variable genes can be identified in silico as they contain easily recognized features such as simple sequence repeats (SSRs) or inverted repeats (IRs) that mediate the random switching of expression. Conversely, phasevarion-controlled genes do not contain any easily identifiable features. The study of DNA methyltransferase specificity using Single-Molecule, Real-Time (SMRT) sequencing and methylome analysis has rapidly advanced the analysis of phasevarions by allowing methylomics to be combined with whole-transcriptome/proteome analysis to comprehensively characterize these systems in a number of important bacterial pathogens.
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Affiliation(s)
- John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia.
| | - Aimee Tan
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, OH 43205, USA
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, 4222, Australia.
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Wanford JJ, Green LR, Aidley J, Bayliss CD. Phasome analysis of pathogenic and commensal Neisseria species expands the known repertoire of phase variable genes, and highlights common adaptive strategies. PLoS One 2018; 13:e0196675. [PMID: 29763438 PMCID: PMC5953494 DOI: 10.1371/journal.pone.0196675] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 04/17/2018] [Indexed: 12/02/2022] Open
Abstract
Pathogenic Neisseria are responsible for significantly higher levels of morbidity and mortality than their commensal relatives despite having similar genetic contents. Neisseria possess a disparate arsenal of surface determinants that facilitate host colonisation and evasion of the immune response during persistent carriage. Adaptation to rapid changes in these hostile host environments is enabled by phase variation (PV) involving high frequency, stochastic switches in expression of surface determinants. In this study, we analysed 89 complete and 79 partial genomes, from the NCBI and Neisseria PubMLST databases, representative of multiple pathogenic and commensal species of Neisseria using PhasomeIt, a new program that identifies putatively phase-variable genes and homology groups by the presence of simple sequence repeats (SSR). We detected a repertoire of 884 putative PV loci with maxima of 54 and 47 per genome in gonococcal and meningococcal isolates, respectively. Most commensal species encoded a lower number of PV genes (between 5 and 30) except N. lactamica wherein the potential for PV (36–82 loci) was higher, implying that PV is an adaptive mechanism for persistence in this species. We also characterised the repeat types and numbers in both pathogenic and commensal species. Conservation of SSR-mediated PV was frequently observed in outer membrane proteins or modifiers of outer membrane determinants. Intermittent and weak selection for evolution of SSR-mediated PV was suggested by poor conservation of tracts with novel PV genes often occurring in only one isolate. Finally, we describe core phasomes—the conserved repertoires of phase-variable genes—for each species that identify overlapping but distinctive adaptive strategies for the pathogenic and commensal members of the Neisseria genus.
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Affiliation(s)
- Joseph J. Wanford
- Department of Genetics and Genome Biology, University of Leicester, Leicestershire, United Kingdom
- * E-mail:
| | - Luke R. Green
- Department of Genetics and Genome Biology, University of Leicester, Leicestershire, United Kingdom
| | - Jack Aidley
- Department of Genetics and Genome Biology, University of Leicester, Leicestershire, United Kingdom
| | - Christopher D. Bayliss
- Department of Genetics and Genome Biology, University of Leicester, Leicestershire, United Kingdom
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Seib KL, Jen FEC, Scott AL, Tan A, Jennings MP. Phase variation of DNA methyltransferases and the regulation of virulence and immune evasion in the pathogenic Neisseria. Pathog Dis 2017; 75:3966716. [DOI: 10.1093/femspd/ftx080] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/13/2017] [Indexed: 01/31/2023] Open
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Tan A, Atack JM, Jennings MP, Seib KL. The Capricious Nature of Bacterial Pathogens: Phasevarions and Vaccine Development. Front Immunol 2016; 7:586. [PMID: 28018352 PMCID: PMC5149525 DOI: 10.3389/fimmu.2016.00586] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 11/28/2016] [Indexed: 12/11/2022] Open
Abstract
Infectious diseases are a leading cause of morbidity and mortality worldwide, and vaccines are one of the most successful and cost-effective tools for disease prevention. One of the key considerations for rational vaccine development is the selection of appropriate antigens. Antigens must induce a protective immune response, and this response should be directed to stably expressed antigens so the target microbe can always be recognized by the immune system. Antigens with variable expression, due to environmental signals or phase variation (i.e., high frequency, random switching of expression), are not ideal vaccine candidates because variable expression could lead to immune evasion. Phase variation is often mediated by the presence of highly mutagenic simple tandem DNA repeats, and genes containing such sequences can be easily identified, and their use as vaccine antigens reconsidered. Recent research has identified phase variably expressed DNA methyltransferases that act as global epigenetic regulators. These phase-variable regulons, known as phasevarions, are associated with altered virulence phenotypes and/or expression of vaccine candidates. As such, genes encoding candidate vaccine antigens that have no obvious mechanism of phase variation may be subject to indirect, epigenetic control as part of a phasevarion. Bioinformatic and experimental studies are required to elucidate the distribution and mechanism of action of these DNA methyltransferases, and most importantly, whether they mediate epigenetic regulation of potential and current vaccine candidates. This process is essential to define the stably expressed antigen target profile of bacterial pathogens and thereby facilitate efficient, rational selection of vaccine antigens.
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Affiliation(s)
- Aimee Tan
- Institute for Glycomics, Griffith University , Gold Coast, QLD , Australia
| | - John M Atack
- Institute for Glycomics, Griffith University , Gold Coast, QLD , Australia
| | - Michael P Jennings
- Institute for Glycomics, Griffith University , Gold Coast, QLD , Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University , Gold Coast, QLD , Australia
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Weigele P, Raleigh EA. Biosynthesis and Function of Modified Bases in Bacteria and Their Viruses. Chem Rev 2016; 116:12655-12687. [PMID: 27319741 DOI: 10.1021/acs.chemrev.6b00114] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Naturally occurring modification of the canonical A, G, C, and T bases can be found in the DNA of cellular organisms and viruses from all domains of life. Bacterial viruses (bacteriophages) are a particularly rich but still underexploited source of such modified variant nucleotides. The modifications conserve the coding and base-pairing functions of DNA, but add regulatory and protective functions. In prokaryotes, modified bases appear primarily to be part of an arms race between bacteriophages (and other genomic parasites) and their hosts, although, as in eukaryotes, some modifications have been adapted to convey epigenetic information. The first half of this review catalogs the identification and diversity of DNA modifications found in bacteria and bacteriophages. What is known about the biogenesis, context, and function of these modifications are also described. The second part of the review places these DNA modifications in the context of the arms race between bacteria and bacteriophages. It focuses particularly on the defense and counter-defense strategies that turn on direct recognition of the presence of a modified base. Where modification has been shown to affect other DNA transactions, such as expression and chromosome segregation, that is summarized, with reference to recent reviews.
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Affiliation(s)
- Peter Weigele
- Chemical Biology, New England Biolabs , Ipswich, Massachusetts 01938, United States
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