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Müller TG, Sakin V, Müller B. A Spotlight on Viruses-Application of Click Chemistry to Visualize Virus-Cell Interactions. Molecules 2019; 24:molecules24030481. [PMID: 30700005 PMCID: PMC6385038 DOI: 10.3390/molecules24030481] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/18/2019] [Accepted: 01/19/2019] [Indexed: 01/03/2023] Open
Abstract
The replication of a virus within its host cell involves numerous interactions between viral and cellular factors, which have to be tightly controlled in space and time. The intricate interplay between viral exploitation of cellular pathways and the intrinsic host defense mechanisms is difficult to unravel by traditional bulk approaches. In recent years, novel fluorescence microscopy techniques and single virus tracking have transformed the investigation of dynamic virus-host interactions. A prerequisite for the application of these imaging-based methods is the attachment of a fluorescent label to the structure of interest. However, their small size, limited coding capacity and multifunctional proteins render viruses particularly challenging targets for fluorescent labeling approaches. Click chemistry in conjunction with genetic code expansion provides virologists with a novel toolbox for site-specific, minimally invasive labeling of virion components, whose potential has just recently begun to be exploited. Here, we summarize recent achievements, current developments and future challenges for the labeling of viral nucleic acids, proteins, glycoproteins or lipids using click chemistry in order to study dynamic processes in virus-cell interactions.
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Affiliation(s)
- Thorsten G Müller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
| | - Volkan Sakin
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
| | - Barbara Müller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
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Damas ND, Fossat N, Scheel TKH. Functional Interplay between RNA Viruses and Non-Coding RNA in Mammals. Noncoding RNA 2019; 5:ncrna5010007. [PMID: 30646609 PMCID: PMC6468702 DOI: 10.3390/ncrna5010007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 12/31/2018] [Accepted: 01/08/2019] [Indexed: 12/12/2022] Open
Abstract
Exploring virus–host interactions is key to understand mechanisms regulating the viral replicative cycle and any pathological outcomes associated with infection. Whereas interactions at the protein level are well explored, RNA interactions are less so. Novel sequencing methodologies have helped uncover the importance of RNA–protein and RNA–RNA interactions during infection. In addition to messenger RNAs (mRNAs), mammalian cells express a great number of regulatory non-coding RNAs, some of which are crucial for regulation of the immune system whereas others are utilized by viruses. It is thus becoming increasingly clear that RNA interactions play important roles for both sides in the arms race between virus and host. With the emerging field of RNA therapeutics, such interactions are promising antiviral targets. In this review, we discuss direct and indirect RNA interactions occurring between RNA viruses or retroviruses and host non-coding transcripts upon infection. In addition, we review RNA virus derived non-coding RNAs affecting immunological and metabolic pathways of the host cell typically to provide an advantage to the virus. The relatively few known examples of virus–host RNA interactions suggest that many more await discovery.
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Affiliation(s)
- Nkerorema Djodji Damas
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Infectious Diseases, Hvidovre Hospital, DK-2650 Hvidovre, Denmark.
| | - Nicolas Fossat
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Infectious Diseases, Hvidovre Hospital, DK-2650 Hvidovre, Denmark.
| | - Troels K H Scheel
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Infectious Diseases, Hvidovre Hospital, DK-2650 Hvidovre, Denmark.
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA.
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Feng Z, Xu K, Kovalev N, Nagy PD. Recruitment of Vps34 PI3K and enrichment of PI3P phosphoinositide in the viral replication compartment is crucial for replication of a positive-strand RNA virus. PLoS Pathog 2019; 15:e1007530. [PMID: 30625229 PMCID: PMC6342326 DOI: 10.1371/journal.ppat.1007530] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/22/2019] [Accepted: 12/16/2018] [Indexed: 12/12/2022] Open
Abstract
Tombusviruses depend on subversions of multiple host factors and retarget cellular pathways to support viral replication. In this work, we demonstrate that tomato bushy stunt virus (TBSV) and the closely-related carnation Italian ringspot virus (CIRV) recruit the cellular Vps34 phosphatidylinositol 3-kinase (PI3K) into the large viral replication compartment. The kinase function of Vps34 is critical for TBSV replication, suggesting that PI(3)P phosphoinositide is utilized by TBSV for building of the replication compartment. We also observed increased expression of Vps34 and the higher abundance of PI(3)P in the presence of the tombusviral replication proteins, which likely leads to more efficient tombusvirus replication. Accordingly, overexpression of PI(3)P phosphatase in yeast or plants inhibited TBSV replication on the peroxisomal membranes and CIRV replication on the mitochondrial membranes. Moreover, the purified PI(3)P phosphatase reduced TBSV replicase assembly in a cell-free system. Detection of PI(3)P with antibody or a bioprobe revealed the enrichment of PI(3)P in the replication compartment. Vps34 is directly recruited into the replication compartment through interaction with p33 replication protein. Gene deletion analysis in surrogate yeast host unraveled that TBSV replication requires the vesicle transport function of Vps34. In the absence of Vps34, TBSV cannot efficiently recruit the Rab5-positive early endosomes, which provide PE-rich membranes for membrane biogenesis of the TBSV replication compartment. We found that Vps34 and PI(3)P needed for the stability of the p33 replication protein, which is degraded by the 26S proteasome when PI(3)P abundance was decreased by an inhibitor of Vps34. In summary, Vps34 and PI(3)P are needed for providing the optimal microenvironment for the replication of the peroxisomal TBSV and the mitochondrial CIRV. Replication of RNA viruses infecting various eukaryotic organisms is the central step in the infection process that leads to generation of progeny viruses. The replication process requires the assembly of numerous viral replicase complexes within the large replication compartment, whose formation is not well understood. Using tombusviruses and the model host yeast, the authors discovered that a highly conserved cellular lipid kinase, Vps34 phosphatidylinositol 3-kinase (PI3K), is critical for the formation of the viral replication compartment. Expression of PI3K mutants and the PI(3)P phosphatase revealed that the PI(3)P phosphoinositide produced by Vps34 is crucial for tombusvirus replication. Tombusviruses co-opt Vps34 through interaction with the viral replication protein into the replication compartment. In vitro reconstitution of the tombusvirus replicase revealed the need for Vps34 and PI(3)P for the full-activity of the viral replicase. Chemical inhibition of Vps34 in yeast or plants showed that PI(3)P is important for the replication of several plant viruses within the Tombusviridae family and the insect-infecting Nodamuravirus. These results open up the possibility that the cellular Vps34 PI3K could be a target for new antiviral strategies.
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Affiliation(s)
- Zhike Feng
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Kai Xu
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, Nanjing, China
- * E-mail: (KX); (PDN)
| | - Nikolay Kovalev
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Peter D. Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail: (KX); (PDN)
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Brown HM, Biering SB, Zhu A, Choi J, Hwang S. Demarcation of Viral Shelters Results in Destruction by Membranolytic GTPases: Antiviral Function of Autophagy Proteins and Interferon-Inducible GTPases. Bioessays 2018; 40:e1700231. [PMID: 29603284 PMCID: PMC5986617 DOI: 10.1002/bies.201700231] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/02/2018] [Indexed: 12/16/2022]
Abstract
A hallmark of positive-sense RNA viruses is the formation of membranous shelters for safe replication in the cytoplasm. Once considered invisible to the immune system, these viral shelters are now found to be antagonized through the cooperation of autophagy proteins and anti-microbial GTPases. This coordinated effort of autophagy proteins guiding GTPases functions against not only the shelters of viruses but also cytoplasmic vacuoles containing bacteria or protozoa, suggesting a broad immune-defense mechanism against disparate vacuolar pathogens. Fundamental questions regarding this process remain: how the host recognizes these membranous structures as a target, how the autophagy proteins bring the GTPases to the shelters, and how the recruited GTPases disrupt these shelters. In this review, these questions are discussed, the answers to which will significantly advance our understanding of the response to vacuole-like structures of pathogens, thereby paving the way for the development of broadly effective anti-microbial strategies for public health.
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Affiliation(s)
- Hailey M. Brown
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
| | - Scott B. Biering
- Committee on Microbiology, The University of Chicago, Chicago, IL 60637, USA
| | - Allen Zhu
- Committee on Cancer Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jayoung Choi
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Seungmin Hwang
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
- Committee on Microbiology, The University of Chicago, Chicago, IL 60637, USA
- Committee on Cancer Biology, The University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
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Liu J, Kline BA, Kenny TA, Smith DR, Soloveva V, Beitzel B, Pang S, Lockett S, Hess HF, Palacios G, Kuhn JH, Sun MG, Zeng X. A novel sheet-like virus particle array is a hallmark of Zika virus infection. Emerg Microbes Infect 2018; 7:69. [PMID: 29691373 PMCID: PMC5915449 DOI: 10.1038/s41426-018-0071-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 02/08/2018] [Accepted: 03/25/2018] [Indexed: 11/08/2022]
Abstract
Zika virus (ZIKV) is an emerging flavivirus that caused thousands of human infections in recent years. Compared to other human flaviviruses, ZIKV replication is not well understood. Using fluorescent, transmission electron, and focused ion beam-scanning electron microscopy, we examined ZIKV replication dynamics in Vero 76 cells and in the brains of infected laboratory mice. We observed the progressive development of a perinuclear flaviviral replication factory both in vitro and in vivo. In vitro, we illustrated the ZIKV lifecycle from particle cell entry to egress. ZIKV particles assembled and aggregated in an induced convoluted membrane structure and ZIKV strain-specific membranous vesicles. While most mature virus particles egressed via membrane budding, some particles also likely trafficked through late endosomes and egressed through membrane abscission. Interestingly, we consistently observed a novel sheet-like virus particle array consisting of a single layer of ZIKV particles. Our study further defines ZIKV replication and identifies a novel hallmark of ZIKV infection.
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Affiliation(s)
- Jun Liu
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA
| | - Brandon A Kline
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA
| | - Tara A Kenny
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA
| | - Darci R Smith
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA
| | - Veronica Soloveva
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA
| | - Brett Beitzel
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA
| | - Song Pang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA
| | - Stephen Lockett
- Optical Microscopy and Analysis Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA
| | - Gustavo Palacios
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, 21702, USA
| | - Mei G Sun
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA.
| | - Xiankun Zeng
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, 21702, USA.
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Biering SB, Choi J, Halstrom RA, Brown HM, Beatty WL, Lee S, McCune BT, Dominici E, Williams LE, Orchard RC, Wilen CB, Yamamoto M, Coers J, Taylor GA, Hwang S. Viral Replication Complexes Are Targeted by LC3-Guided Interferon-Inducible GTPases. Cell Host Microbe 2017; 22:74-85.e7. [PMID: 28669671 PMCID: PMC5591033 DOI: 10.1016/j.chom.2017.06.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 04/14/2017] [Accepted: 06/08/2017] [Indexed: 12/22/2022]
Abstract
All viruses with positive-sense RNA genomes replicate on membranous structures in the cytoplasm called replication complexes (RCs). RCs provide an advantageous microenvironment for viral replication, but it is unknown how the host immune system counteracts these structures. Here we show that interferon-gamma (IFNG) disrupts the RC of murine norovirus (MNV) via evolutionarily conserved autophagy proteins and the induction of IFN-inducible GTPases, which are known to destroy the membrane of vacuoles containing bacteria, protists, or fungi. The MNV RC was marked by the microtubule-associated-protein-1-light-chain-3 (LC3) conjugation system of autophagy and then targeted by immunity-related GTPases (IRGs) and guanylate-binding proteins (GBPs) upon their induction by IFNG. Further, the LC3 conjugation system and the IFN-inducible GTPases were necessary to inhibit MNV replication in mice and human cells. These data suggest that viral RCs can be marked and antagonized by a universal immune defense mechanism targeting diverse pathogens replicating in cytosolic membrane structures.
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Affiliation(s)
- Scott B Biering
- Committee on Microbiology, University of Chicago, Chicago, IL 60637, USA
| | - Jayoung Choi
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Rachel A Halstrom
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Hailey M Brown
- Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sanghyun Lee
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Broc T McCune
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Erin Dominici
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Lelia E Williams
- Biological Sciences Collegiate Division, University of Chicago, Chicago, IL 60637, USA
| | - Robert C Orchard
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Craig B Wilen
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Masahiro Yamamoto
- Laboratory of Immunoparasitology, World Premier International Research Center Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan
| | - Jörn Coers
- Departments of Medicine, Molecular Genetics and Microbiology, and Immunology, Duke University Medical Center, Durham, NC 27710, USA
| | - Gregory A Taylor
- Departments of Medicine, Molecular Genetics and Microbiology, and Immunology, Duke University Medical Center, Durham, NC 27710, USA; GRECC, Durham VA Health Care System, Durham, NC 27705, USA
| | - Seungmin Hwang
- Committee on Microbiology, University of Chicago, Chicago, IL 60637, USA; Department of Pathology, University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, University of Chicago, Chicago, IL 60637, USA.
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Interleukin-2 enhancer binding factor 2 interacts with the nsp9 or nsp2 of porcine reproductive and respiratory syndrome virus and exerts negatively regulatory effect on the viral replication. Virol J 2017; 14:125. [PMID: 28693575 PMCID: PMC5504599 DOI: 10.1186/s12985-017-0794-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/03/2017] [Indexed: 11/30/2022] Open
Abstract
Background Porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive failures in sows and respiratory diseases in growing pigs, resulting in huge economic loss for the pig production worldwide. The nonstructural protein 9 (nsp9) and nonstructural protein 2 (nsp2) of PRRSV are known to play important roles in viral replication. Cellular interleukin-2 enhancer binding factor 2 (ILF2) participates in many cellular pathways and involves in life cycle of some viruses. In the present study, we analyzed the interaction of cellular ILF2 with the nsp9 and nsp2 of PRRSV in vitro and explored the effect of ILF2 on viral replication. Methods The interaction of ILF2 with the nsp9 or nsp2 of PRRSV was analyzed in 293FT cells and MARC-145 cells by co-immunoprecipitation (Co-IP) and the co-localization of ILF2 with the nsp9 or nsp2 of PRRSV in MARC-145 cell and pulmonary alveolar macrophages (PAMs) was examined by confocal immunofluorescence assay. The effect of ILF2 knockdown and over-expression on PRRSV replication was explored in MARC-145 cells by small interfering RNA (siRNA) and lentivirus transduction, respectively. Results The interaction of ILF2 with nsp9 or nsp2 was first demonstrated in 293FT cells co-transfected with ILF2-expressing plasmid and nsp9-expressing plasmid or nsp2-expressing plasmid. The interaction of endogenous ILF2 with the nsp9 or nsp2 of PRRSV was further confirmed in MARC-145 cells transduced with GFP-nsp9-expressing lentiviruses or infected with PRRSV JXwn06. The RdRp domain of nsp9 was shown to be responsible for its interaction with ILF2, while three truncated nsp2 were shown to interact with ILF2. Moreover, we observed that ILF2 partly translocated from the nucleus to the cytoplasm and co-localized with nsp9 and nsp2 in PRRSV-infected MARC-145 cells and PAMs. Finally, our analysis indicated that knockdown of ILF2 favored the replication of PRRSV, while over-expression of ILF2 impaired the viral replication in MARC-145 cells. Conclusion Our findings are the first to confirm that the porcine ILF2 interacts with the nsp9 and nsp2 of PRRSV in vitro, and exerts negatively regulatory effect on the replication of PRRSV. Our present study provides more evidence for understanding the roles of the interactions between cellular proteins and viral proteins in the replication of PRRSV. Electronic supplementary material The online version of this article (doi:10.1186/s12985-017-0794-5) contains supplementary material, which is available to authorized users.
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Scutigliani EM, Kikkert M. Interaction of the innate immune system with positive-strand RNA virus replication organelles. Cytokine Growth Factor Rev 2017; 37:17-27. [PMID: 28709747 PMCID: PMC7108334 DOI: 10.1016/j.cytogfr.2017.05.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 05/15/2017] [Indexed: 02/08/2023]
Abstract
All +RNA viruses induce replication organelles to shield viral RNA from innate immune surveillance. Recent literature suggests that non-self or aberrant-self membrane structures can be tagged with LC3 or ubiquitin. Interferon-induced GTPases then recognize these tags and destroy the membrane structures, thereby exposing PAMPs. More research will have to indicate whether this is a general antiviral mechanism affecting +RNA virus infections.
The potential health risks associated with (re-)emerging positive-strand RNA (+RNA) viruses emphasizes the need for understanding host-pathogen interactions for these viruses. The innate immune system forms the first line of defense against pathogenic organisms like these and is responsible for detecting pathogen-associated molecular patterns (PAMPs). Viral RNA is a potent inducer of antiviral innate immune signaling, provoking an antiviral state by directing expression of interferons (IFNs) and pro-inflammatory cytokines. However, +RNA viruses developed various methods to avoid detection and downstream signaling, including isolation of viral RNA replication in membranous viral replication organelles (ROs). These structures therefore play a central role in infection, and consequently, loss of RO integrity might simultaneously result in impaired viral replication and enhanced antiviral signaling. This review summarizes the first indications that the innate immune system indeed has tools to disrupt viral ROs and other non- or aberrant-self membrane structures, and may do this by marking these membranes with proteins such as microtubule-associated protein 1A/1B-light chain 3 (LC3) and ubiquitin, resulting in the recruitment of IFN-inducible GTPases. Further studies should evaluate whether this process forms a general effector mechanism in +RNA virus infection, thereby creating the opportunity for development of novel antiviral therapies.
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Affiliation(s)
- Enzo Maxim Scutigliani
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marjolein Kikkert
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
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The ins and outs of eukaryotic viruses: Knowledge base and ontology of a viral infection. PLoS One 2017; 12:e0171746. [PMID: 28207819 PMCID: PMC5313201 DOI: 10.1371/journal.pone.0171746] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/25/2017] [Indexed: 12/19/2022] Open
Abstract
Viruses are genetically diverse, infect a wide range of tissues and host cells and follow unique processes for replicating themselves. All these processes were investigated and indexed in ViralZone knowledge base. To facilitate standardizing data, a simple ontology of viral life-cycle terms was developed to provide a common vocabulary for annotating data sets. New terminology was developed to address unique viral replication cycle processes, and existing terminology was modified and adapted. The virus life-cycle is classically described by schematic pictures. Using this ontology, it can be represented by a combination of successive terms: “entry”, “latency”, “transcription”, “replication” and “exit”. Each of these parts is broken down into discrete steps. For example Zika virus “entry” is broken down in successive steps: “Attachment”, “Apoptotic mimicry”, “Viral endocytosis/ macropinocytosis”, “Fusion with host endosomal membrane”, “Viral factory”. To demonstrate the utility of a standard ontology for virus biology, this work was completed by annotating virus data in the ViralZone, UniProtKB and Gene Ontology databases.
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Tatineni S, French R. The Coat Protein and NIa Protease of Two Potyviridae Family Members Independently Confer Superinfection Exclusion. J Virol 2016; 90:10886-10905. [PMID: 27681136 PMCID: PMC5110166 DOI: 10.1128/jvi.01697-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 09/20/2016] [Indexed: 01/13/2023] Open
Abstract
Superinfection exclusion (SIE) is an antagonistic virus-virus interaction whereby initial infection by one virus prevents subsequent infection by closely related viruses. Although SIE has been described in diverse viruses infecting plants, humans, and animals, its mechanisms, including involvement of specific viral determinants, are just beginning to be elucidated. In this study, SIE determinants encoded by two economically important wheat viruses, Wheat streak mosaic virus (WSMV; genus Tritimovirus, family Potyviridae) and Triticum mosaic virus (TriMV; genus Poacevirus, family Potyviridae), were identified in gain-of-function experiments that used heterologous viruses to express individual virus-encoded proteins in wheat. Wheat plants infected with TriMV expressing WSMV P1, HC-Pro, P3, 6K1, CI, 6K2, NIa-VPg, or NIb cistrons permitted efficient superinfection by WSMV expressing green fluorescent protein (WSMV-GFP). In contrast, wheat infected with TriMV expressing WSMV NIa-Pro or coat protein (CP) substantially excluded superinfection by WSMV-GFP, suggesting that both of these cistrons are SIE effectors encoded by WSMV. Importantly, SIE is due to functional WSMV NIa-Pro or CP rather than their encoding RNAs, as altering the coded protein products by minimally changing RNA sequences led to abolishment of SIE. Deletion mutagenesis further revealed that elicitation of SIE by NIa-Pro requires the entire protein while CP requires only a 200-amino-acid (aa) middle fragment (aa 101 to 300) of the 349 aa. Strikingly, reciprocal experiments with WSMV-mediated expression of TriMV proteins showed that TriMV CP, and TriMV NIa-Pro to a lesser extent, likewise excluded superinfection by TriMV-GFP. Collectively, these data demonstrate that WSMV- and TriMV-encoded CP and NIa-Pro proteins are effectors of SIE and that these two proteins trigger SIE independently of each other. IMPORTANCE Superinfection exclusion (SIE) is an antagonistic virus-virus interaction that prevents secondary invasions by identical or closely related viruses in the same host cells. Although known to occur in diverse viruses, SIE remains an enigma in terms of key molecular determinants and action mechanisms. In this study, we found that Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) encode two independently functioning cistrons that serve as effectors of SIE at the protein but not the RNA level. The coat protein and NIa-Pro encoded by these two viruses, when expressed from a heterologous virus, exerted SIE to the cognate viruses. The identification of virus-encoded effectors of SIE and their transgenic expression could potentially facilitate the development of virus-resistant crop plants. Additionally, functional conservation of SIE in diverse virus groups suggests that a better understanding of the underlying mechanisms of SIE could facilitate the development of novel antiviral therapies against viral diseases.
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Affiliation(s)
- Satyanarayana Tatineni
- United States Department of Agriculture-Agricultural Research Service and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Roy French
- United States Department of Agriculture-Agricultural Research Service and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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