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Juhas M. Multidrug-Resistant Bacteria. BRIEF LESSONS IN MICROBIOLOGY 2023:65-77. [DOI: 10.1007/978-3-031-29544-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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2
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Juhas M. Gene Transfer. BRIEF LESSONS IN MICROBIOLOGY 2023:51-63. [DOI: 10.1007/978-3-031-29544-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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3
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SV40 T-antigen uses a DNA shearing mechanism to initiate origin unwinding. Proc Natl Acad Sci U S A 2022; 119:e2216240119. [PMID: 36442086 PMCID: PMC9894130 DOI: 10.1073/pnas.2216240119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Duplication of DNA genomes requires unwinding of the double-strand (ds) DNA so that each single strand (ss) can be copied by a DNA polymerase. The genomes of eukaryotic cells are unwound by two ring-shaped hexameric helicases that initially encircle dsDNA but transition to ssDNA for function as replicative helicases. How the duplex is initially unwound, and the role of the two helicases in this process, is poorly understood. We recently described an initiation mechanism for eukaryotes in which the two helicases are directed inward toward one another and shear the duplex open by pulling on opposite strands of the duplex while encircling dsDNA [L. D. Langston, M. E. O'Donnell, eLife 8, e46515 (2019)]. Two head-to-head T-Antigen helicases are long known to be loaded at the SV40 origin. We show here that T-Antigen tracks head (N-tier) first on ssDNA, opposite the direction proposed for decades. We also find that SV40 T-Antigen tracks directionally while encircling dsDNA and mainly tracks on one strand of the duplex in the same orientation as during ssDNA translocation. Further, two inward directed T-Antigen helicases on dsDNA are able to melt a 150-bp duplex. These findings explain the "rabbit ear" DNA loops observed at the SV40 origin by electron microscopy and reconfigure how the DNA loops emerge from the double hexamer relative to earlier models. Thus, the mechanism of DNA shearing by two opposing helicases is conserved in a eukaryotic viral helicase and may be widely used to initiate origin unwinding of dsDNA genomes.
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Qiao C, Debiasi-Anders G, Mir-Sanchis I. Staphylococcal self-loading helicases couple the staircase mechanism with inter domain high flexibility. Nucleic Acids Res 2022; 50:8349-8362. [PMID: 35871290 PMCID: PMC9371898 DOI: 10.1093/nar/gkac625] [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: 05/26/2022] [Revised: 06/24/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
Replication is a crucial cellular process. Replicative helicases unwind DNA providing the template strand to the polymerase and promoting replication fork progression. Helicases are multi-domain proteins which use an ATPase domain to couple ATP hydrolysis with translocation, however the role that the other domains might have during translocation remains elusive. Here, we studied the unexplored self-loading helicases called Reps, present in Staphylococcus aureus pathogenicity islands (SaPIs). Our cryoEM structures of the PriRep5 from SaPI5 (3.3 Å), the Rep1 from SaPI1 (3.9 Å) and Rep1–DNA complex (3.1Å) showed that in both Reps, the C-terminal domain (CTD) undergoes two distinct movements respect the ATPase domain. We experimentally demonstrate both in vitro and in vivo that SaPI-encoded Reps need key amino acids involved in the staircase mechanism of translocation. Additionally, we demonstrate that the CTD′s presence is necessary for the maintenance of full ATPase and helicase activities. We speculate that this high interdomain flexibility couples Rep′s activities as initiators and as helicases.
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Affiliation(s)
- Cuncun Qiao
- Department of Medical Biochemistry and Biophysics, Umeå University , Umeå , Sweden
- Wallenberg Centre for Molecular Medicine , Umeå , Sweden
| | - Gianluca Debiasi-Anders
- Department of Medical Biochemistry and Biophysics, Umeå University , Umeå , Sweden
- Wallenberg Centre for Molecular Medicine , Umeå , Sweden
| | - Ignacio Mir-Sanchis
- Department of Medical Biochemistry and Biophysics, Umeå University , Umeå , Sweden
- Wallenberg Centre for Molecular Medicine , Umeå , Sweden
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Barth ZK, Silvas TV, Angermeyer A, Seed KD. Genome replication dynamics of a bacteriophage and its satellite reveal strategies for parasitism and viral restriction. Nucleic Acids Res 2020; 48:249-263. [PMID: 31667508 PMCID: PMC7145576 DOI: 10.1093/nar/gkz1005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 09/14/2019] [Accepted: 10/17/2019] [Indexed: 12/13/2022] Open
Abstract
Phage-inducible chromosomal island-like elements (PLEs) are bacteriophage satellites found in Vibrio cholerae. PLEs parasitize the lytic phage ICP1, excising from the bacterial chromosome, replicating, and mobilizing to new host cells following cell lysis. PLEs protect their host cell populations by completely restricting the production of ICP1 progeny. Previously, it was found that ICP1 replication was reduced during PLE(+) infection. Despite robust replication of the PLE genome, relatively few transducing units are produced. We investigated if PLE DNA replication itself is antagonistic to ICP1 replication. Here we identify key constituents of PLE replication and assess their role in interference of ICP1. PLE encodes a RepA_N initiation factor that is sufficient to drive replication from the PLE origin of replication during ICP1 infection. In contrast to previously characterized bacteriophage satellites, expression of the PLE initiation factor was not sufficient for PLE replication in the absence of phage. Replication of PLE was necessary for interference of ICP1 DNA replication, but replication of a minimalized PLE replicon was not sufficient for ICP1 DNA replication interference. Despite restoration of ICP1 DNA replication, non-replicating PLE remained broadly inhibitory against ICP1. These results suggest that PLE DNA replication is one of multiple mechanisms contributing to ICP1 restriction.
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Affiliation(s)
- Zachary K Barth
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Tania V Silvas
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Angus Angermeyer
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kimberley D Seed
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA.,Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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6
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Novick RP. Pathogenicity Islands and Their Role in Staphylococcal Biology. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0062-2019. [PMID: 31172913 PMCID: PMC11257176 DOI: 10.1128/microbiolspec.gpp3-0062-2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Indexed: 12/20/2022] Open
Abstract
Pathogenicity islands are members of a vast collection of genomic islands that encode important virulence, antibiotic resistance and other accessory functions and have a critical role in bacterial gene transfer. Staphylococcus aureus is host to a large family of such islands, known as SaPIs, which encode super antigen and other virulence determinants, are mobilized by helper phages and transferred at extremely high frequencies. They benefit their host cells by interfering with phage predation and enhancing horizontal gene transfer. This chapter describes their life cycle, the bases of their phage interference mechanisms, their transfer system and their conversion to antibacterial agents for treatment ofstaphylococcal infections.
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Affiliation(s)
- Richard P Novick
- NYU School of Medicine, Skirball Institute of Biomolecular Medicine and Departments of Medicine and Microbiology, New York, NY 10016
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Carpena N, Manning KA, Dokland T, Marina A, Penadés JR. Convergent evolution of pathogenicity islands in helper cos phage interference. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0505. [PMID: 27672154 PMCID: PMC5052747 DOI: 10.1098/rstb.2015.0505] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2016] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus pathogenicity islands (SaPIs) are phage satellites that exploit the life cycle of their helper phages for their own benefit. Most SaPIs are packaged by their helper phages using a headful (pac) packaging mechanism. These SaPIs interfere with pac phage reproduction through a variety of strategies, including the redirection of phage capsid assembly to form small capsids, a process that depends on the expression of the SaPI-encoded cpmA and cpmB genes. Another SaPI subfamily is induced and packaged by cos-type phages, and although these cos SaPIs also block the life cycle of their inducing phages, the basis for this mechanism of interference remains to be deciphered. Here we have identified and characterized one mechanism by which the SaPIs interfere with cos phage reproduction. This mechanism depends on a SaPI-encoded gene, ccm, which encodes a protein involved in the production of small isometric capsids, compared with the prolate helper phage capsids. As the Ccm and CpmAB proteins are completely unrelated in sequence, this strategy represents a fascinating example of convergent evolution. Moreover, this result also indicates that the production of SaPI-sized particles is a widespread strategy of phage interference conserved during SaPI evolution. This article is part of the themed issue ‘The new bacteriology’.
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Affiliation(s)
- Nuria Carpena
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK Departamento de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad CEU Cardenal Herrera, 46113 Moncada, Valencia, Spain
| | - Keith A Manning
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Terje Dokland
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Alberto Marina
- Instituto de Biomedicina de Valencia (IBV-CSIC) and CIBER de Enfermedades Raras (CIBERER), 46010 Valencia, Spain
| | - José R Penadés
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
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Penadés JR, Christie GE. The Phage-Inducible Chromosomal Islands: A Family of Highly Evolved Molecular Parasites. Annu Rev Virol 2016; 2:181-201. [PMID: 26958912 DOI: 10.1146/annurev-virology-031413-085446] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The phage-inducible chromosomal islands (PICIs) are a family of highly mobile genetic elements that contribute substantively to horizontal gene transfer, host adaptation, and virulence. Initially identified in Staphylococcus aureus, these elements are now thought to occur widely in gram-positive bacteria. They are molecular parasites that exploit certain temperate phages as helpers, using a variety of elegant strategies to manipulate the phage life cycle and promote their own spread, both intra- and intergenerically. At the same time, these PICI-encoded mechanisms severely interfere with helper phage reproduction, thereby enhancing survival of the bacterial population. In this review we discuss the genetics and the life cycle of these elements, with special emphasis on how they interact and interfere with the helper phage machinery for their own benefit. We also analyze the role that these elements play in driving bacterial and viral evolution.
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Affiliation(s)
- José R Penadés
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, G12 8TA Glasgow, United Kingdom;
| | - Gail E Christie
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298;
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Staphylococcal SCCmec elements encode an active MCM-like helicase and thus may be replicative. Nat Struct Mol Biol 2016; 23:891-898. [PMID: 27571176 PMCID: PMC5052118 DOI: 10.1038/nsmb.3286] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 08/05/2016] [Indexed: 01/07/2023]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a public-health threat worldwide. Although the mobile genomic island responsible for this phenotype, staphylococcal cassette chromosome (SCC), has been thought to be nonreplicative, we predicted DNA-replication-related functions for some of the conserved proteins encoded by SCC. We show that one of these, Cch, is homologous to the self-loading initiator helicases of an unrelated family of genomic islands, that it is an active 3'-to-5' helicase and that the adjacent ORF encodes a single-stranded DNA-binding protein. Our 2.9-Å crystal structure of intact Cch shows that it forms a hexameric ring. Cch, like the archaeal and eukaryotic MCM-family replicative helicases, belongs to the pre-sensor II insert clade of AAA+ ATPases. Additionally, we found that SCC elements are part of a broader family of mobile elements, all of which encode a replication initiator upstream of their recombinases. Replication after excision would enhance the efficiency of horizontal gene transfer.
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Suzuki Y, Kubota H, Sato'o Y, Ono H, Kato R, Sadamasu K, Kai A, Kamata Y. Identification and characterization of novel Staphylococcus aureus
pathogenicity islands encoding staphylococcal enterotoxins originating from staphylococcal food poisoning isolates. J Appl Microbiol 2015; 118:1507-20. [DOI: 10.1111/jam.12786] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 02/20/2015] [Accepted: 02/24/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Y. Suzuki
- Department of Veterinary Medicine; Faculty of Agriculture; Iwate University; Morioka City Iwate Japan
- The United Graduate School of Veterinary Sciences; Gifu University; Gifu City Gifu Japan
- Department of Microbiology; Tokyo Metropolitan Institute of Public Health; Shinjuku-ku Tokyo Japan
| | - H. Kubota
- Department of Microbiology; Tokyo Metropolitan Institute of Public Health; Shinjuku-ku Tokyo Japan
| | - Y. Sato'o
- Department of Bacteriology; Hiroshima University Graduate School of Biomedical and Health Sciences; Hiroshima City Hiroshima Japan
| | - H.K. Ono
- Department of Microbiology and Immunology; Hirosaki University Graduate School of Medicine; Hirosaki City Aomori Japan
| | - R. Kato
- Department of Microbiology; Tokyo Metropolitan Institute of Public Health; Shinjuku-ku Tokyo Japan
| | - K. Sadamasu
- Department of Microbiology; Tokyo Metropolitan Institute of Public Health; Shinjuku-ku Tokyo Japan
| | - A. Kai
- Department of Microbiology; Tokyo Metropolitan Institute of Public Health; Shinjuku-ku Tokyo Japan
| | - Y. Kamata
- Department of Veterinary Medicine; Faculty of Agriculture; Iwate University; Morioka City Iwate Japan
- The United Graduate School of Veterinary Sciences; Gifu University; Gifu City Gifu Japan
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11
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Sequence determinants for DNA packaging specificity in the S. aureus pathogenicity island SaPI1. Plasmid 2013; 71:8-15. [PMID: 24365721 DOI: 10.1016/j.plasmid.2013.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/10/2013] [Accepted: 12/13/2013] [Indexed: 11/21/2022]
Abstract
The SaPIs and their relatives are a family of genomic islands that exploit helper phages for high frequency horizontal transfer. One of the mechanisms used by SaPIs to accomplish this molecular piracy is the redirection of the helper phage DNA packaging machinery. SaPIs encode a small terminase subunit that can be substituted for that of the phage. In this study we have determined the initial packaging cleavage sites for helper phage 80α, which uses the phage-encoded small terminase subunit, and for SaPI1, which uses the SaPI-encoded small terminase subunit. We have identified a 19nt SaPI1 sequence that is necessary and sufficient to allow high frequency 80α transduction of a plasmid by a terminase carrying the SaPI1-encoded small subunit. We also show that the hybrid enzyme with the SaPI1 small terminase subunit is capable of generalized transduction.
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Abstract
Horizontal gene transfer has a tremendous impact on the genome plasticity, adaptation and evolution of bacteria. Horizontally transferred mobile genetic elements are involved in the dissemination of antibiotic resistance and virulence genes, thus contributing to the emergence of novel "superbugs". This review provides update on various mechanisms of horizontal gene transfer and examines how horizontal gene transfer contributes to the evolution of pathogenic bacteria. Special focus is paid to the role horizontal gene transfer plays in pathogenicity of the emerging human pathogens: hypervirulent Clostridium difficile and Escherichia coli (including the most recent haemolytic uraemic syndrome outbreak strain) and methicillin-resistant Staphylococcus aureus (MRSA), which have been associated with largest outbreaks of infection recently.
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Affiliation(s)
- Mario Juhas
- Department of Pathology, University of Cambridge , Cambridge , UK
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13
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Staphylococcal pathogenicity island interference with helper phage reproduction is a paradigm of molecular parasitism. Proc Natl Acad Sci U S A 2012; 109:16300-5. [PMID: 22991467 DOI: 10.1073/pnas.1204615109] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Staphylococcal pathogenicity islands (SaPIs) carry superantigen and resistance genes and are extremely widespread in Staphylococcus aureus and in other Gram-positive bacteria. SaPIs represent a major source of intrageneric horizontal gene transfer and a stealth conduit for intergeneric gene transfer; they are phage satellites that exploit the life cycle of their temperate helper phages with elegant precision to enable their rapid replication and promiscuous spread. SaPIs also interfere with helper phage reproduction, blocking plaque formation, sharply reducing burst size and enhancing the survival of host cells following phage infection. Here, we show that SaPIs use several different strategies for phage interference, presumably the result of convergent evolution. One strategy, not described previously in the bacteriophage microcosm, involves a SaPI-encoded protein that directly and specifically interferes with phage DNA packaging by blocking the phage terminase small subunit. Another strategy involves interference with phage reproduction by diversion of the vast majority of virion proteins to the formation of SaPI-specific small infectious particles. Several SaPIs use both of these strategies, and at least one uses neither but possesses a third. Our studies illuminate a key feature of the evolutionary strategy of these mobile genetic elements, in addition to their carriage of important genes-interference with helper phage reproduction, which could ensure their transferability and long-term persistence.
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