1
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Knodel MM, Nägel A, Herrmann E, Wittum G. Intracellular "In Silico Microscopes"-Comprehensive 3D Spatio-Temporal Virus Replication Model Simulations. Viruses 2024; 16:840. [PMID: 38932132 PMCID: PMC11209084 DOI: 10.3390/v16060840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/09/2024] [Accepted: 04/20/2024] [Indexed: 06/28/2024] Open
Abstract
Despite their small and simple structure compared with their hosts, virus particles can cause severe harm and even mortality in highly evolved species such as humans. A comprehensive quantitative biophysical understanding of intracellular virus replication mechanisms could aid in preparing for future virus pandemics. By elucidating the relationship between the form and function of intracellular structures from the host cell and viral components, it is possible to identify possible targets for direct antiviral agents and potent vaccines. Biophysical investigations into the spatio-temporal dynamics of intracellular virus replication have thus far been limited. This study introduces a framework to enable simulations of these dynamics using partial differential equation (PDE) models, which are evaluated using advanced numerical mathematical methods on leading supercomputers. In particular, this study presents a model of the replication cycle of a specific RNA virus, the hepatitis C virus. The diffusion-reaction model mimics the interplay of the major components of the viral replication cycle, including non structural viral proteins, viral genomic RNA, and a generic host factor. Technically, surface partial differential equations (sufPDEs) are coupled on the 3D embedded 2D endoplasmic reticulum manifold with partial differential equations (PDEs) in the 3D membranous web and cytosol volume. The membranous web serves as a viral replication factory and is formed on the endoplasmic reticulum after infection and in the presence of nonstructural proteins. The coupled sufPDE/PDE model was evaluated using realistic cell geometries based on experimental data. The simulations incorporate the effects of non structural viral proteins, which are restricted to the endoplasmic reticulum surface, with effects appearing in the volume, such as host factor supply from the cytosol and membranous web dynamics. Because the spatial diffusion properties of genomic viral RNA are not yet fully understood, the model allows for viral RNA movement on the endoplasmic reticulum as well as within the cytosol. Visualizing the simulated intracellular viral replication dynamics provides insights similar to those obtained by microscopy, complementing data from in vitro/in vivo viral replication experiments. The output data demonstrate quantitative consistence with the experimental findings, prompting further advanced experimental studies to validate the model and refine our quantitative biophysical understanding.
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Affiliation(s)
| | - Arne Nägel
- Modular Supercomputing and Quantum Computing (MSQC), Goethe-Universität Frankfurt, 60325 Frankfurt am Main, Germany;
| | - Eva Herrmann
- Institute for Biostatistics und Mathematical Modelling (IBMM), Goethe-Universität Frankfurt, 60590 Frankfurt am Main, Germany;
| | - Gabriel Wittum
- Modelling and Simulation (MaS), Computer, Electrical and Mathematical Science and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia;
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2
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Jablunovsky A, Jose J. The Dynamic Landscape of Capsid Proteins and Viral RNA Interactions in Flavivirus Genome Packaging and Virus Assembly. Pathogens 2024; 13:120. [PMID: 38392858 PMCID: PMC10893219 DOI: 10.3390/pathogens13020120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
The Flavivirus genus of the Flaviviridae family of enveloped single-stranded RNA viruses encompasses more than 70 members, many of which cause significant disease in humans and livestock. Packaging and assembly of the flavivirus RNA genome is essential for the formation of virions, which requires intricate coordination of genomic RNA, viral structural, and nonstructural proteins in association with virus-induced, modified endoplasmic reticulum (ER) membrane structures. The capsid (C) protein, a small but versatile RNA-binding protein, and the positive single-stranded RNA genome are at the heart of the elusive flavivirus assembly process. The nucleocapsid core, consisting of the genomic RNA encapsidated by C proteins, buds through the ER membrane, which contains viral glycoproteins prM and E organized as trimeric spikes into the lumen, forming an immature virus. During the maturation process, which involves the low pH-mediated structural rearrangement of prM and E and furin cleavage of prM in the secretory pathway, the spiky immature virus with a partially ordered nucleocapsid core becomes a smooth, mature virus with no discernible nucleocapsid. This review focuses on the mechanisms of genome packaging and assembly by examining the structural and functional aspects of C protein and viral RNA. We review the current lexicon of critical C protein features and evaluate interactions between C and genomic RNA in the context of assembly and throughout the life cycle.
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Affiliation(s)
- Anastazia Jablunovsky
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA;
| | - Joyce Jose
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA;
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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3
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Papadopoulou G, Petroulia S, Karamichali E, Dimitriadis A, Marousis D, Ioannidou E, Papazafiri P, Koskinas J, Foka P, Georgopoulou U. The Epigenetic Controller Lysine-Specific Demethylase 1 (LSD1) Regulates the Outcome of Hepatitis C Viral Infection. Cells 2023; 12:2568. [PMID: 37947646 PMCID: PMC10648375 DOI: 10.3390/cells12212568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023] Open
Abstract
Hepatitis C virus (HCV) alters gene expression epigenetically to rearrange the cellular microenvironment in a beneficial way for its life cycle. The host epigenetic changes induced by HCV lead to metabolic dysfunction and malignant transformation. Lysine-specific demethylase 1 (LSD1) is an epigenetic controller of critical cellular functions that are essential for HCV propagation. We investigated the putative role of LSD1 in the establishment of HCV infection using genetic engineering and pharmacological inhibition to alter endogenous LSD1 levels. We demonstrated for the first time that HCV replication was inhibited in LSD1-overexpressing cells, while specific HCV proteins differentially fine-tuned endogenous LSD1 expression levels. Electroporation of the full-length HCV genome and subgenomic replicons in LSD1 overexpression enhanced translation and partially restored HCV replication, suggesting that HCV might be inhibited by LSD1 during the early steps of infection. Conversely, the inhibition of LSD1, followed by HCV infection in vitro, increased viral replication. LSD1 was shown to participate in an intriguing antiviral mechanism, where it activates endolysosomal interferon-induced transmembrane protein 3 (IFITM3) via demethylation, leading endocytosed HCV virions to degradation. Our study proposes that HCV-mediated LSD1 oscillations over countless viral life cycles throughout chronic HCV infection may promote epigenetic changes related to HCV-induced hepatocarcinogenesis.
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Affiliation(s)
- Georgia Papadopoulou
- Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
- Division of Animal and Human Physiology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
| | - Stavroula Petroulia
- Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Eirini Karamichali
- Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Alexios Dimitriadis
- Molecular Biology and Immunobiotechnology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Dimitrios Marousis
- Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Elisavet Ioannidou
- Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Panagiota Papazafiri
- Division of Animal and Human Physiology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
| | - John Koskinas
- 2nd Department of Internal Medicine, Medical School of Athens, Hippokration General Hospital, 11521 Athens, Greece
| | - Pelagia Foka
- Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Urania Georgopoulou
- Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece
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4
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Islam KU, Anwar S, Patel AA, Mirdad MT, Mirdad MT, Azmi MI, Ahmad T, Fatima Z, Iqbal J. Global Lipidome Profiling Revealed Multifaceted Role of Lipid Species in Hepatitis C Virus Replication, Assembly, and Host Antiviral Response. Viruses 2023; 15:v15020464. [PMID: 36851679 PMCID: PMC9965260 DOI: 10.3390/v15020464] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/29/2023] [Accepted: 02/01/2023] [Indexed: 02/11/2023] Open
Abstract
Hepatitis C virus (HCV) is a major human pathogen that requires a better understanding of its interaction with host cells. There is a close association of HCV life cycle with host lipid metabolism. Lipid droplets (LDs) have been found to be crucial organelles that support HCV replication and virion assembly. In addition to their role in replication, LDs also have protein-mediated antiviral properties that are activated during HCV infection. Studies have shown that HCV replicates well in cholesterol and sphingolipid-rich membranes, but the ways in which HCV alters host cell lipid dynamics are not yet known. In this study, we performed a kinetic study to check the enrichment of LDs at different time points of HCV infection. Based on the LD enrichment results, we selected early and later time points of HCV infection for global lipidomic study. Early infection represents the window period for HCV sensing and host immune response while later infection represents the establishment of viral RNA replication, virion assembly, and egress. We identified the dynamic profile of lipid species at early and later time points of HCV infection by global lipidomic study using mass spectrometry. At early HCV infection, phosphatidylinositol phospholipids (PIPs), lysophosphatidic acid (LPA), triacyl glycerols (TAG), phosphatidylcholine (PC), and trihexosylceramides (Hex3Cer) were observed to be enriched. Similarly, free fatty acids (FFA), phosphatidylethanolamine (PE), N-acylphosphatidylethanolamines (NAPE), and tri acylglycerols were enriched at later time points of HCV infection. Lipids enriched at early time of infection may have role in HCV sensing, viral attachment, and immune response as LPA and PIPs are important for immune response and viral attachment, respectively. Moreover, lipid species observed at later infection may contribute to HCV replication and virion assembly as PE, FFA, and triacylglycerols are known for the similar function. In conclusion, we identified lipid species that exhibited dynamic profile across early and later time points of HCV infection compared to mock cells, which could be therapeutically relevant in the design of more specific and effective anti-viral therapies.
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Affiliation(s)
- Khursheed Ul Islam
- Multidisciplinary Center for Advanced Research and Studies, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Saleem Anwar
- Multidisciplinary Center for Advanced Research and Studies, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Ayyub A. Patel
- Department of Clinical Biochemistry, College of Medicine, King Khalid University, Abha 62529, Saudi Arabia
| | | | | | - Md Iqbal Azmi
- Multidisciplinary Center for Advanced Research and Studies, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Tanveer Ahmad
- Multidisciplinary Center for Advanced Research and Studies, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Zeeshan Fatima
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, University of Bisha, Bisha 61922, Saudi Arabia
- Amity Institute of Biotechnology, Amity University Haryana, Manesar, Gurugram 122413, India
- Correspondence: (Z.F.); (J.I.)
| | - Jawed Iqbal
- Multidisciplinary Center for Advanced Research and Studies, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
- Correspondence: (Z.F.); (J.I.)
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5
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WTAP Targets the METTL3 m 6A-Methyltransferase Complex to Cytoplasmic Hepatitis C Virus RNA to Regulate Infection. J Virol 2022; 96:e0099722. [PMID: 36314819 PMCID: PMC9683008 DOI: 10.1128/jvi.00997-22] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Modification of the hepatitis C virus (HCV) positive-strand RNA genome by N6-methyladenosine (m6A) regulates the viral life cycle. This life cycle takes place solely in the cytoplasm, while m6A addition on cellular mRNA takes place in the nucleus. Thus, the mechanisms by which m6A is deposited on the viral RNA have been unclear. In this work, we find that m6A modification of HCV RNA by the m6A-methyltransferase proteins methyltransferase-like 3 and 14 (METTL3 and METTL14) is regulated by Wilms' tumor 1-associating protein (WTAP). WTAP, a predominantly nuclear protein, is an essential member of the cellular mRNA m6A-methyltransferase complex and known to target METTL3 to mRNA. We found that HCV infection induces localization of WTAP to the cytoplasm. Importantly, we found that WTAP is required for both METTL3 interaction with HCV RNA and m6A modification across the viral RNA genome. Further, we found that WTAP, like METTL3 and METTL14, negatively regulates the production of infectious HCV virions, a process that we have previously shown is regulated by m6A. Excitingly, WTAP regulation of both HCV RNA m6A modification and virion production was independent of its ability to localize to the nucleus. Together, these results reveal that WTAP is critical for HCV RNA m6A modification by METTL3 and METTL14 in the cytoplasm. IMPORTANCE Positive-strand RNA viruses such as HCV represent a significant global health burden. Previous work has described that HCV RNA contains the RNA modification m6A and how this modification regulates viral infection. Yet, how this modification is targeted to HCV RNA has remained unclear due to the incompatibility of the nuclear cellular processes that drive m6A modification with the cytoplasmic HCV life cycle. In this study, we present evidence for how m6A modification is targeted to HCV RNA in the cytoplasm by a mechanism in which WTAP recruits the m6A-methyltransferase METTL3 to HCV RNA. This targeting strategy for m6A modification of cytoplasmic RNA viruses is likely relevant for other m6A-modified positive-strand RNA viruses with cytoplasmic life cycles such as enterovirus 71 and SARS-CoV-2 and provides an exciting new target for potential antiviral therapies.
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6
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Herod MR, Ward JC, Tuplin A, Harris M, Stonehouse NJ, McCormick CJ. Positive strand RNA viruses differ in the constraints they place on the folding of their negative strand. RNA (NEW YORK, N.Y.) 2022; 28:1359-1376. [PMID: 35918125 PMCID: PMC9479745 DOI: 10.1261/rna.079125.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Genome replication of positive strand RNA viruses requires the production of a complementary negative strand RNA that serves as a template for synthesis of more positive strand progeny. Structural RNA elements are important for genome replication, but while they are readily observed in the positive strand, evidence of their existence in the negative strand is more limited. We hypothesized that this was due to viruses differing in their capacity to allow this latter RNA to adopt structural folds. To investigate this, ribozymes were introduced into the negative strand of different viral constructs; the expectation being that if RNA folding occurred, negative strand cleavage and suppression of replication would be seen. Indeed, this was what happened with hepatitis C virus (HCV) and feline calicivirus (FCV) constructs. However, little or no impact was observed for chikungunya virus (CHIKV), human rhinovirus (HRV), hepatitis E virus (HEV), and yellow fever virus (YFV) constructs. Reduced cleavage in the negative strand proved to be due to duplex formation with the positive strand. Interestingly, ribozyme-containing RNAs also remained intact when produced in vitro by the HCV polymerase, again due to duplex formation. Overall, our results show that there are important differences in the conformational constraints imposed on the folding of the negative strand between different positive strand RNA viruses.
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Affiliation(s)
- Morgan R Herod
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Joseph C Ward
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Andrew Tuplin
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Nicola J Stonehouse
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Christopher J McCormick
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, University Hospital Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton SO17 1BJ, United Kingdom
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7
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Sacco MT, Bland KM, Horner SM. WTAP targets the METTL3 m 6 A-methyltransferase complex to cytoplasmic hepatitis C virus RNA to regulate infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.06.27.497872. [PMID: 35794896 PMCID: PMC9258289 DOI: 10.1101/2022.06.27.497872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
UNLABELLED Modification of the hepatitis C virus (HCV) positive-strand RNA genome by N6-methyladenosine (m 6 A) regulates the viral lifecycle. This lifecycle takes place solely in the cytoplasm, while m 6 A addition on cellular mRNA takes place in the nucleus. Thus, the mechanisms by which m 6 A is deposited on the viral RNA have been unclear. In this work, we find that m 6 A modification of HCV RNA by the m 6 A-methyltransferase proteins METTL3 and METTL14 is regulated by WTAP. WTAP, a predominantly nuclear protein, is an essential member of the cellular mRNA m 6 A-methyltransferase complex and known to target METTL3 to mRNA. We found that HCV infection induces localization of WTAP to the cytoplasm. Importantly, we found that WTAP is required for both METTL3 interaction with HCV RNA and for m 6 A modification across the viral RNA genome. Further, we found that WTAP, like METTL3 and METTL14, negatively regulates the production of infectious HCV virions, a process that we have previously shown is regulated by m 6 A. Excitingly, WTAP regulation of both HCV RNA m 6 A modification and virion production were independent of its ability to localize to the nucleus. Together, these results reveal that WTAP is critical for HCV RNA m 6 A modification by METTL3 and METTL14 in the cytoplasm. IMPORTANCE Positive-strand RNA viruses such as HCV represent a significant global health burden. Previous work has described how HCV RNA contains the RNA modification m 6 A and how this modification regulates viral infection. Yet, how this modification is targeted to HCV RNA has remained unclear due to the incompatibility of the nuclear cellular processes that drive m 6 A modification with the cytoplasmic HCV lifecycle. In this study, we present evidence for how m 6 A modification is targeted to HCV RNA in the cytoplasm by a mechanism in which WTAP recruits the m 6 A-methyltransferase METTL3 to HCV RNA. This targeting strategy for m 6 A modification of cytoplasmic RNA viruses is likely relevant for other m 6 A-modified positive-strand RNA viruses with cytoplasmic lifecycles such as enterovirus 71 and SARS-CoV-2 and provides an exciting new target for potential antiviral therapies.
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8
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Lee JY, Wing PAC, Gala DS, Noerenberg M, Järvelin AI, Titlow J, Zhuang X, Palmalux N, Iselin L, Thompson MK, Parton RM, Prange-Barczynska M, Wainman A, Salguero FJ, Bishop T, Agranoff D, James W, Castello A, McKeating JA, Davis I. Absolute quantitation of individual SARS-CoV-2 RNA molecules provides a new paradigm for infection dynamics and variant differences. eLife 2022; 11:74153. [PMID: 35049501 PMCID: PMC8776252 DOI: 10.7554/elife.74153] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/21/2021] [Indexed: 12/11/2022] Open
Abstract
Despite an unprecedented global research effort on SARS-CoV-2, early replication events remain poorly understood. Given the clinical importance of emergent viral variants with increased transmission, there is an urgent need to understand the early stages of viral replication and transcription. We used single-molecule fluorescence in situ hybridisation (smFISH) to quantify positive sense RNA genomes with 95% detection efficiency, while simultaneously visualising negative sense genomes, subgenomic RNAs, and viral proteins. Our absolute quantification of viral RNAs and replication factories revealed that SARS-CoV-2 genomic RNA is long-lived after entry, suggesting that it avoids degradation by cellular nucleases. Moreover, we observed that SARS-CoV-2 replication is highly variable between cells, with only a small cell population displaying high burden of viral RNA. Unexpectedly, the B.1.1.7 variant, first identified in the UK, exhibits significantly slower replication kinetics than the Victoria strain, suggesting a novel mechanism contributing to its higher transmissibility with important clinical implications.
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Affiliation(s)
- Jeffrey Y Lee
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Peter AC Wing
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Chinese Academy of Medical Sciences (CAMS) Oxford Institute (COI), The University of OxfordOxfordUnited Kingdom
| | - Dalia S Gala
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Marko Noerenberg
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom,MRC-University of Glasgow Centre for Virus Research, The University of GlasgowGlasgowUnited Kingdom
| | - Aino I Järvelin
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Joshua Titlow
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Xiaodong Zhuang
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom
| | - Natasha Palmalux
- MRC-University of Glasgow Centre for Virus Research, The University of GlasgowGlasgowUnited Kingdom
| | - Louisa Iselin
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Mary Kay Thompson
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Richard M Parton
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Maria Prange-Barczynska
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Ludwig Institute for Cancer Research, The University of OxfordOxfordUnited Kingdom
| | - Alan Wainman
- Sir William Dunn School of Pathology, The University of OxfordOxfordUnited Kingdom
| | | | - Tammie Bishop
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Ludwig Institute for Cancer Research, The University of OxfordOxfordUnited Kingdom
| | - Daniel Agranoff
- Department of Infectious Diseases, University Hospitals Sussex NHS Foundation TrustBrightonUnited Kingdom
| | - William James
- Sir William Dunn School of Pathology, The University of OxfordOxfordUnited Kingdom,James & Lillian Martin Centre, Sir William Dunn School of Pathology, The University of OxfordOxfordUnited Kingdom
| | - Alfredo Castello
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom,MRC-University of Glasgow Centre for Virus Research, The University of GlasgowGlasgowUnited Kingdom
| | - Jane A McKeating
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Chinese Academy of Medical Sciences (CAMS) Oxford Institute (COI), The University of OxfordOxfordUnited Kingdom
| | - Ilan Davis
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
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9
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Zhang J, Li H, Lin B, Luo X, Yin P, Yi T, Xue B, Zhang XL, Zhu H, Nie Z. Development of Near-Infrared Nucleic Acid Mimics of Fluorescent Proteins for In Vivo Imaging of Viral RNA with Turn-On Fluorescence. J Am Chem Soc 2021; 143:19317-19329. [PMID: 34762804 DOI: 10.1021/jacs.1c04577] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
GFP-like fluorescent proteins and their molecular mimics have revolutionized bioimaging research, but their emissions are largely limited in the visible to far-red region, hampering the in vivo applications in intact animals. Herein, we structurally modulate GFP-like chromophores using a donor-acceptor-acceptor (D-A-A') molecular configuration to discover a set of novel fluorogenic derivatives with infrared-shifted spectra. These chromophores can be fluorescently elicited by their specific interaction with G-quadruplex (G4), a unique noncanonical nucleic acid secondary structure, via inhibition of the chromophores' twisted-intramolecular charge transfer. This feature allows us to create, for the first time, FP mimics with tunable emission in the near-infrared (NIR) region (Emmax = 664-705 nm), namely, infrared G-quadruplex mimics of FPs (igMFP). Compared with their FP counterparts, igMFPs exhibit remarkably higher quantum yields, larger Stokes shift, and better photostability. In a proof-of-concept application using pathogen-related G4s as the target, we exploited igMFPs to directly visualize native hepatitis C virus (HCV) RNA genome in living cells via their in situ formation by the chromophore-bound viral G4 structure in the HCV core gene. Furthermore, igMFPs are capable of high contrast HCV RNA imaging in living mice bearing a HCV RNA-presenting mini-organ, providing the first application of FP mimics in whole-animal imaging.
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Affiliation(s)
- Jiaheng Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha 410082, People's Republic of China
| | - Huiyi Li
- Institute of Pathogen Biology and Immunology of College of Biology, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, People's Republic of China
| | - Bin Lin
- Pharmaceutical Engineering & Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, People's Republic of China
| | - Xingyu Luo
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha 410082, People's Republic of China
| | - Peng Yin
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha 410082, People's Republic of China
| | - Ting Yi
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha 410082, People's Republic of China
| | - Binbin Xue
- Institute of Pathogen Biology and Immunology of College of Biology, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, People's Republic of China
| | - Xiao-Lian Zhang
- State Key Laboratory of Virology and Hubei Province Key Laboratory of Allergy and Immunology and Department of Immunology, School of Medicine, Wuhan University, Wuhan 430071, Hubei, People's Republic of China
| | - Haizhen Zhu
- Institute of Pathogen Biology and Immunology of College of Biology, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, People's Republic of China
| | - Zhou Nie
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha 410082, People's Republic of China
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10
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Li C, Zhang W, Shi B, Chen G, Zheng Y, An Y, Sun M, Feng Y, Shang Q, Zhang X. Evaluation of the in situ assay for HBV DNA: An observational real-world study in chronic hepatitis B. Medicine (Baltimore) 2021; 100:e27220. [PMID: 34664859 PMCID: PMC8448054 DOI: 10.1097/md.0000000000027220] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 08/28/2021] [Indexed: 02/06/2023] Open
Abstract
The visualization of intrahepatic hepatitis B virus (HBV) DNA by in situ hybridization (ISH) has uncovered some interesting aspects of HBV life cycle at the single-cell level. In the current study, we intend to evaluate the reliability and robustness of this assay in the real-world clinical scenario and its relationship with currently available clinical biomarkers in chronic hepatitis B (CHB) patients.In this cross-sectional study, 94 CHB patients and 10 patients with non-HBV related liver diseases were enrolled. Liver biopsies and routine histopathology analysis were performed. Intrahepatic HBV DNA and viral antigens (HBsAg and HBcAg) were detected by ISH and immunohistochemistry (IHC), respectively. The basic biochemical and virological parameters such as alanine transaminase, serum HBV DNA, and serum HBsAg were measured.The HBV DNA-ISH assay showed 55.8% (53/94 cases) positive rate in CHB patients, no false positive was found in non-HBV related hepatitis. The IHC of HBsAg and HBcAg showed a positive rate of 94.7% (89/94 cases) and 19.5% (17/87 cases), respectively. Quantification of HBV DNA-ISH signal showed a significant correlation with serum HBV DNA (rs = 0.6223, P < .0001). In addition, the staining pattern of HBV DNA in situ in the context of collagen deposition informed the histopathological progression of chronic liver disease.The application of this ISH assay in evaluating intrahepatic viral replication in real-world CHB patients showed favorable performance. It can be a complementation to conventional liver histopathology examination and IHC detection of viral antigens. This methodology provides an intuitive assessment of virological and pathological state of CHB patients, and further supports clinical diagnosis and management.
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Affiliation(s)
- Chang Li
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Wei Zhang
- Chinese PLA Diagnosis and Treatment Center for Liver Diseases, The 960th Hospital of Chinese PLA Joint Logistics Support Force, Tai’an, Shandong, China
| | - Bisheng Shi
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Gang Chen
- Chinese PLA Diagnosis and Treatment Center for Liver Diseases, The 960th Hospital of Chinese PLA Joint Logistics Support Force, Tai’an, Shandong, China
| | - Ye Zheng
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Yong An
- Chinese PLA Diagnosis and Treatment Center for Liver Diseases, The 960th Hospital of Chinese PLA Joint Logistics Support Force, Tai’an, Shandong, China
| | - Mimi Sun
- Chinese PLA Diagnosis and Treatment Center for Liver Diseases, The 960th Hospital of Chinese PLA Joint Logistics Support Force, Tai’an, Shandong, China
| | - Yanling Feng
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Qinghua Shang
- Chinese PLA Diagnosis and Treatment Center for Liver Diseases, The 960th Hospital of Chinese PLA Joint Logistics Support Force, Tai’an, Shandong, China
| | - Xiaonan Zhang
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- Centre for Research in Therapeutic Solutions, Biomedical Sciences, Faculty of Science and Technology, University of Canberra, ACT, Australia
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11
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Yue L, Li C, Xu M, Wu M, Ding J, Liu J, Zhang X, Yuan Z. Probing the spatiotemporal patterns of HBV multiplication reveals novel features of its subcellular processes. PLoS Pathog 2021; 17:e1009838. [PMID: 34370796 PMCID: PMC8376071 DOI: 10.1371/journal.ppat.1009838] [Citation(s) in RCA: 7] [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: 02/16/2021] [Revised: 08/19/2021] [Accepted: 07/25/2021] [Indexed: 02/06/2023] Open
Abstract
Through evolution, Hepatitis B Virus (HBV) developed highly intricate mechanisms exploiting host resources for its multiplication within a constrained genetic coding capacity. Yet a clear picture of viral hitchhiking of cellular processes with spatial resolution is still largely unsolved. Here, by leveraging bDNA-based fluorescence in situ hybridization (FISH) combined with immunofluorescence, we developed a microscopic approach for multiplex detection of viral nucleic acids and proteins, which enabled us to probe some of the key aspects of HBV life cycle. We confirmed the slow kinetics and revealed the high variability of viral replication at single-cell level. We directly visualized HBV minichromosome in contact with acetylated histone 3 and RNA polymerase II and observed HBV-induced degradation of Smc5/6 complex only in primary hepatocytes. We quantified the frequency of HBV pregenomic RNAs occupied by translating ribosome or capsids. Statistics at molecular level suggested a rapid translation phase followed by a slow encapsidation and maturation phase. Finally, the roles of microtubules (MTs) on nucleocapsid assembly and virion morphogenesis were analyzed. Disruption of MTs resulted in the perinuclear retention of nucleocapsid. Meanwhile, large multivesicular body (MVB) formation was significantly disturbed as evidenced by the increase in number and decrease in volume of CD63+ vesicles, thus inhibiting mature virion secretion. In conclusion, these data provided spatially resolved molecular snapshots in the context of specific subcellular activities. The heterogeneity observed at single-cell level afforded valuable molecular insights which are otherwise unavailable from bulk measurements. HBV is a hepatotropic, enveloped virus with a partially double-stranded relaxed circular DNA genome. Studies on the molecular biology of HBV mainly rely on biochemical extraction and bulk quantification methods. Detailed spatiotemporal information on virus components in subcellular context is still lacking. Here, we re-evaluated the reproduction schemes of HBV by fluorescence in situ hybridization (FISH). We visualized cccDNA minichromosome formation in an epigenetic context, identified pgRNA associated with actively translating ribosomes and capsids. Moreover, the active participation of microtubules in nucleocapsid transport and MVB-mediated virion secretion was identified. These observations have broad implications for understanding the HBV replication cycle and may facilitate the identification of novel antiviral targets.
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Affiliation(s)
- Lei Yue
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Chang Li
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Mingzhu Xu
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Min Wu
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Jiahui Ding
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jiangxia Liu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xiaonan Zhang
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- Centre for Research in Therapeutic Solutions, Biomedical Sciences, Faculty of Science and Technology, University of Canberra, ACT, Australia
- * E-mail: (XZ); (ZY)
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- * E-mail: (XZ); (ZY)
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12
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Initial HCV infection of adult hepatocytes triggers a temporally structured transcriptional program containing diverse pro- and anti-viral elements. J Virol 2021; 95:JVI.00245-21. [PMID: 33658347 PMCID: PMC8139656 DOI: 10.1128/jvi.00245-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Transcriptional profiling provides global snapshots of virus-mediated cellular reprogramming, which can simultaneously encompass pro- and antiviral components. To determine early transcriptional signatures associated with HCV infection of authentic target cells, we performed ex vivo infections of adult primary human hepatocytes (PHHs) from seven donors. Longitudinal sampling identified minimal gene dysregulation at six hours post infection (hpi). In contrast, at 72 hpi, massive increases in the breadth and magnitude of HCV-induced gene dysregulation were apparent, affecting gene classes associated with diverse biological processes. Comparison with HCV-induced transcriptional dysregulation in Huh-7.5 cells identified limited overlap between the two systems. Of note, in PHHs, HCV infection initiated broad upregulation of canonical interferon (IFN)-mediated defense programs, limiting viral RNA replication and abrogating virion release. We further find that constitutive expression of IRF1 in PHHs maintains a steady-state antiviral program in the absence of infection, which can additionally reduce HCV RNA translation and replication. We also detected infection-induced downregulation of ∼90 genes encoding components of the EIF2 translation initiation complex and ribosomal subunits in PHHs, consistent with a signature of translational shutoff. As HCV polyprotein translation occurs independently of the EIF2 complex, this process is likely pro-viral: only translation initiation of host transcripts is arrested. The combination of antiviral intrinsic and inducible immunity, balanced against pro-viral programs, including translational arrest, maintains HCV replication at a low-level in PHHs. This may ultimately keep HCV under the radar of extra-hepatocyte immune surveillance while initial infection is established, promoting tolerance, preventing clearance and facilitating progression to chronicity.IMPORTANCEAcute HCV infections are often asymptomatic and therefore frequently undiagnosed. We endeavored to recreate this understudied phase of HCV infection using explanted PHHs and monitored host responses to initial infection. We detected temporally distinct virus-induced perturbations in the transcriptional landscape, which were initially narrow but massively amplified in breadth and magnitude over time. At 72 hpi, we detected dysregulation of diverse gene programs, concurrently promoting both virus clearance and virus persistence. On the one hand, baseline expression of IRF1 combined with infection-induced upregulation of IFN-mediated effector genes suppresses virus propagation. On the other, we detect transcriptional signatures of host translational inhibition, which likely reduces processing of IFN-regulated gene transcripts and facilitates virus survival. Together, our data provide important insights into constitutive and virus-induced transcriptional programs in PHHs, and identifies simultaneous antagonistic dysregulation of pro-and anti-viral programs which may facilitate host tolerance and promote viral persistence.
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13
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Riva L, Spriet C, Barois N, Popescu CI, Dubuisson J, Rouillé Y. Comparative Analysis of Hepatitis C Virus NS5A Dynamics and Localization in Assembly-Deficient Mutants. Pathogens 2021; 10:pathogens10020172. [PMID: 33557275 PMCID: PMC7919264 DOI: 10.3390/pathogens10020172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/26/2021] [Accepted: 01/30/2021] [Indexed: 12/17/2022] Open
Abstract
The hepatitis C virus (HCV) life cycle is a tightly regulated process, during which structural and non-structural proteins cooperate. However, the interplay between HCV proteins during genomic RNA replication and progeny virion assembly is not completely understood. Here, we studied the dynamics and intracellular localization of non-structural 5A protein (NS5A), which is a protein involved both in genome replication and encapsidation. An NS5A-eGFP (enhanced green fluorescent protein) tagged version of the strain JFH-1-derived wild-type HCV was compared to the corresponding assembly-deficient viruses Δcore, NS5A basic cluster 352–533 mutant (BCM), and serine cluster 451 + 454 + 457 mutant (SC). These analyses highlighted an increase of NS5A motility when the viral protein core was lacking. Although to a lesser extent, NS5A motility was also increased in the BCM virus, which is characterized by a lack of interaction of NS5A with the viral RNA, impairing HCV genome encapsidation. This observation suggests that the more static NS5A population is mainly involved in viral assembly rather than in RNA replication. Finally, NS4B exhibited a reduced co-localization with NS5A and lipid droplets for both Δcore and SC mutants, which is characterized by the absence of interaction of NS5A with core. This observation strongly suggests that NS5A is involved in targeting NS4B to lipid droplets (LDs). In summary, this work contributes to a better understanding of the interplay between HCV proteins during the viral life cycle.
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Affiliation(s)
- Laura Riva
- University of Lille, CNRS, Inserm, Institut Pasteur de Lille, CHU Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, 59000 Lille, France; (L.R.); (N.B.); (J.D.)
| | - Corentin Spriet
- University of Lille, CNRS, UMR 8576-UGSF-Department of Functional and Structural Glycobiology, 59000 Lille, France;
- University of Lille, CNRS, Inserm, Institut Pasteur de Lille, CHU Lille, US 41-UMS 2014-PLBS, 59000 Lille, France
| | - Nicolas Barois
- University of Lille, CNRS, Inserm, Institut Pasteur de Lille, CHU Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, 59000 Lille, France; (L.R.); (N.B.); (J.D.)
- University of Lille, CNRS, Inserm, Institut Pasteur de Lille, CHU Lille, US 41-UMS 2014-PLBS, 59000 Lille, France
| | - Costin-Ioan Popescu
- Institute of Biochemistry of the Romanian Academy, 060031 Bucharest, Romania;
| | - Jean Dubuisson
- University of Lille, CNRS, Inserm, Institut Pasteur de Lille, CHU Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, 59000 Lille, France; (L.R.); (N.B.); (J.D.)
| | - Yves Rouillé
- University of Lille, CNRS, Inserm, Institut Pasteur de Lille, CHU Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, 59000 Lille, France; (L.R.); (N.B.); (J.D.)
- Correspondence:
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14
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Vassilaki N, Frakolaki E, Kalliampakou KI, Sakellariou P, Kotta-Loizou I, Bartenschlager R, Mavromara P. A Novel Cis-Acting RNA Structural Element Embedded in the Core Coding Region of the Hepatitis C Virus Genome Directs Internal Translation Initiation of the Overlapping Core+1 ORF. Int J Mol Sci 2020; 21:ijms21186974. [PMID: 32972019 PMCID: PMC7554737 DOI: 10.3390/ijms21186974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/04/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) genome translation is initiated via an internal ribosome entry site (IRES) embedded in the 5'-untranslated region (5'UTR). We have earlier shown that the conserved RNA stem-loops (SL) SL47 and SL87 of the HCV core-encoding region are important for viral genome translation in cell culture and in vivo. Moreover, we have reported that an open reading frame overlapping the core gene in the +1 frame (core+1 ORF) encodes alternative translation products, including a protein initiated at the internal AUG codons 85/87 of this frame (nt 597-599 and 603-605), downstream of SL87, which is designated core+1/Short (core+1/S). Here, we provide evidence for SL47 and SL87 possessing a novel cis-acting element that directs the internal translation initiation of core+1/S. Firstly, using a bicistronic dual luciferase reporter system and RNA-transfection experiments, we found that nucleotides 344-596 of the HCV genotype-1a and -2a genomes support translation initiation at the core+1 frame AUG codons 85/87, when present in the sense but not the opposite orientation. Secondly, site-directed mutagenesis combined with an analysis of ribosome-HCV RNA association elucidated that SL47 and SL87 are essential for this alternative translation mechanism. Finally, experiments using cells transfected with JFH1 replicons or infected with virus-like particles showed that core+1/S expression is independent from the 5'UTR IRES and does not utilize the polyprotein initiation codon, but it requires intact SL47 and SL87 structures. Thus, SL47 and SL87, apart from their role in viral polyprotein translation, are necessary elements for mediating the internal translation initiation of the alternative core+1/S ORF.
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Affiliation(s)
- Niki Vassilaki
- Molecular Virology Laboratory, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (E.F.); (K.I.K.); (P.S.); (I.K.-L.)
- Correspondence: (N.V.); (P.M.)
| | - Efseveia Frakolaki
- Molecular Virology Laboratory, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (E.F.); (K.I.K.); (P.S.); (I.K.-L.)
| | - Katerina I. Kalliampakou
- Molecular Virology Laboratory, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (E.F.); (K.I.K.); (P.S.); (I.K.-L.)
| | - Panagiotis Sakellariou
- Molecular Virology Laboratory, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (E.F.); (K.I.K.); (P.S.); (I.K.-L.)
| | - Ioly Kotta-Loizou
- Molecular Virology Laboratory, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (E.F.); (K.I.K.); (P.S.); (I.K.-L.)
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany;
- German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Penelope Mavromara
- Molecular Virology Laboratory, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (E.F.); (K.I.K.); (P.S.); (I.K.-L.)
- Laboratory of Biochemistry and Molecular Virology, Department of Molecular Biology and Genetics, Democritus University of Thrace, 68100 Thrace, Greece
- Correspondence: (N.V.); (P.M.)
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15
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Dinan AM, Lukhovitskaya NI, Olendraite I, Firth AE. A case for a negative-strand coding sequence in a group of positive-sense RNA viruses. Virus Evol 2020; 6:veaa007. [PMID: 32064120 PMCID: PMC7010960 DOI: 10.1093/ve/veaa007] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Positive-sense single-stranded RNA viruses form the largest and most diverse group of eukaryote-infecting viruses. Their genomes comprise one or more segments of coding-sense RNA that function directly as messenger RNAs upon release into the cytoplasm of infected cells. Positive-sense RNA viruses are generally accepted to encode proteins solely on the positive strand. However, we previously identified a surprisingly long (∼1,000-codon) open reading frame (ORF) on the negative strand of some members of the family Narnaviridae which, together with RNA bacteriophages of the family Leviviridae, form a sister group to all other positive-sense RNA viruses. Here, we completed the genomes of three mosquito-associated narnaviruses, all of which have the long reverse-frame ORF. We systematically identified narnaviral sequences in public data sets from a wide range of sources, including arthropod, fungal, and plant transcriptomic data sets. Long reverse-frame ORFs are widespread in one clade of narnaviruses, where they frequently occupy >95 per cent of the genome. The reverse-frame ORFs correspond to a specific avoidance of CUA, UUA, and UCA codons (i.e. stop codon reverse complements) in the forward-frame RNA-dependent RNA polymerase ORF. However, absence of these codons cannot be explained by other factors such as inability to decode these codons or GC3 bias. Together with other analyses, we provide the strongest evidence yet of coding capacity on the negative strand of a positive-sense RNA virus. As these ORFs comprise some of the longest known overlapping genes, their study may be of broad relevance to understanding overlapping gene evolution and de novo origin of genes.
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Affiliation(s)
- Adam M Dinan
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Nina I Lukhovitskaya
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Ingrida Olendraite
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
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16
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Lee KM, Wu CC, Wu SE, Lin YH, Wang LT, Chang CR, Huang PN, Shih SR, Kuo RL. The RNA-dependent RNA polymerase of enterovirus A71 associates with ribosomal proteins and positively regulates protein translation. RNA Biol 2020; 17:608-622. [PMID: 32009553 DOI: 10.1080/15476286.2020.1722448] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Enteroviruses, which may cause neurological complications, have become a public health threat worldwide in recent years. Interactions between cellular proteins and enteroviral proteins could interfere with cellular biological processes to facilitate viral replication in infected cells. Enteroviral RNA-dependent RNA polymerase (RdRP), known as 3D protein, mainly functions as a replicase for viral RNA synthesis in infected cells. However, the 3D protein encoded by enterovirus A71 (EV-A71) could also interact with several cellular proteins to regulate cellular events and responses during infection. To globally investigate the functions of the EV-A71 3D protein in regulating biological processes in host cells, we performed immunoprecipitation coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify host proteins that may associate with the 3D protein. We found that the 3D protein interacts with factors involved in translation-related biological processes, including ribosomal proteins. In addition, polysome profiling analysis showed that the 3D protein cosediments with small and large subunits of ribosomes. We further discovered that the EV-A71 3D protein could enhance EV-A71 internal ribosome entry site (IRES)-dependent translation as well as cap-dependent translation. Collectively, this research demonstrated that the RNA polymerase encoded by EV-A71 could join a functional ribosomal complex and positively regulate viral and host translation.
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Affiliation(s)
- Kuo-Ming Lee
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Ching Wu
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Otolaryngology-Head & Neck Surgery, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Shang-En Wu
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ya-Han Lin
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Li-Ting Wang
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Ru Chang
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Peng-Nien Huang
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shin-Ru Shih
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Clinical Virology Laboratory, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Rei-Lin Kuo
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Division of Allergy, Asthma, and Rheumatology, Department of Pediatrics, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
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17
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Pan TC, Lo CW, Chong WM, Tsai CN, Lee KY, Chen PY, Liao JC, Yu MJ. Differential Proteomics Reveals Discrete Functions of Proteins Interacting with Hypo- versus Hyper-phosphorylated NS5A of the Hepatitis C Virus. J Proteome Res 2019; 18:2813-2825. [PMID: 31199160 DOI: 10.1021/acs.jproteome.9b00130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Protein phosphorylation is a reversible post-translational modification that regulates many biological processes in almost all living forms. In the case of the hepatitis C virus (HCV), the nonstructural protein 5A (NS5A) is believed to transit between hypo- and hyper-phosphorylated forms that interact with host proteins to execute different functions; however, little was known about the proteins that bind either form of NS5A. Here, we generated two high-quality antibodies specific to serine 235 nonphosphorylated hypo- vs serine 235 phosphorylated (pS235) hyper-phosphorylated form of NS5A and for the first time segregated these two forms of NS5A plus their interacting proteins for dimethyl-labeling based proteomics. We identified 629 proteins, of which 238 were quantified in three replicates. Bioinformatics showed 46 proteins that preferentially bind hypo-phosphorylated NS5A are involved in antiviral response and another 46 proteins that bind pS235 hyper-phosphorylated NS5A are involved in liver cancer progression. We further identified a DNA-dependent kinase (DNA-PK) that binds hypo-phosphorylated NS5A. Inhibition of DNA-PK with an inhibitor or via gene-specific knockdown significantly reduced S232 phosphorylation and NS5A hyper-phosphorylation. Because S232 phosphorylation initiates sequential S232/S235/S238 phosphorylation leading to NS5A hyper-phosphorylation, we identified a new protein kinase that regulates a delicate balance of NS5A between hypo- and hyper-phosphorylation states, respectively, involved in host antiviral responses and liver cancer progression.
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Affiliation(s)
- Ting-Chun Pan
- Institute of Biochemistry and Molecular Biology, College of Medicine , National Taiwan University , Taipei 10051 , Taiwan
| | - Chieh-Wen Lo
- Institute of Biochemistry and Molecular Biology, College of Medicine , National Taiwan University , Taipei 10051 , Taiwan
| | - Weng Man Chong
- Institute of Atomic and Molecular Sciences , Academia Sinica , Taipei 10617 , Taiwan
| | - Chia-Ni Tsai
- Institute of Biochemistry and Molecular Biology, College of Medicine , National Taiwan University , Taipei 10051 , Taiwan
| | - Kuan-Ying Lee
- Institute of Biochemistry and Molecular Biology, College of Medicine , National Taiwan University , Taipei 10051 , Taiwan
| | - Pin-Yin Chen
- Institute of Biochemistry and Molecular Biology, College of Medicine , National Taiwan University , Taipei 10051 , Taiwan
| | - Jung-Chi Liao
- Institute of Atomic and Molecular Sciences , Academia Sinica , Taipei 10617 , Taiwan
| | - Ming-Jiun Yu
- Institute of Biochemistry and Molecular Biology, College of Medicine , National Taiwan University , Taipei 10051 , Taiwan
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18
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Luo X, Xue B, Feng G, Zhang J, Lin B, Zeng P, Li H, Yi H, Zhang XL, Zhu H, Nie Z. Lighting up the Native Viral RNA Genome with a Fluorogenic Probe for the Live-Cell Visualization of Virus Infection. J Am Chem Soc 2019; 141:5182-5191. [PMID: 30860368 DOI: 10.1021/jacs.8b10265] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
RNA viruses represent a major global health threat, and the visualization of their RNA genome in infected cells is essential for virological research and clinical diagnosis. Due to the lack of chemical toolkits for the live-cell imaging of viral RNA genomes, especially native viral genomes without labeling and genetic modification, studies on native virus infection at the single-live-cell level are challenging. Herein, taking hepatitis C virus (HCV) as a representative RNA virus, we propose that the innate noncanonical G-quadruplex (G4) structure of viral RNA can serve as a specific imaging target and report a new benzothiazole-based G4-targeted fluorescence light-up probe, ThT-NE, for the direct visualization of the native RNA genome of HCV in living host cells. We demonstrate the use of the ThT-NE probe for several previously intractable applications, including the sensitive detection of individual virus-infected cells by small-molecule staining, real-time monitoring of the subcellular distribution of the viral RNA genome in live cells, and continuous live-cell tracking of the infection and propagation of clinically isolated native HCV. The fluorogenic-probe-based viral RNA light-up system opens up a promising chemical strategy for cutting-edge live-cell viral analysis, providing a potentially powerful tool for viral biology, medical diagnosis, and drug development.
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Affiliation(s)
- Xingyu Luo
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , People's Republic of China
| | - Binbin Xue
- Institute of Pathogen Biology and Immunology of College of Biology, State Key Laboratory of Chemo/Biosensing and Chemometrics , Hunan University , Changsha 410082 , People's Republic of China
| | - Guangfu Feng
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , People's Republic of China
| | - Jiaheng Zhang
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , People's Republic of China
| | - Bin Lin
- Pharmaceutical Engineering & Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , People's Republic of China
| | - Pan Zeng
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , People's Republic of China
| | - Huiyi Li
- Institute of Pathogen Biology and Immunology of College of Biology, State Key Laboratory of Chemo/Biosensing and Chemometrics , Hunan University , Changsha 410082 , People's Republic of China
| | - Haibo Yi
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , People's Republic of China
| | - Xiao-Lian Zhang
- State Key Laboratory of Virology and Hubei Province Key Laboratory of Allergy and Immunology and Department of Immunology, School of Medicine , Wuhan University , Wuhan 430071 , Hubei , People's Republic of China
| | - Haizhen Zhu
- Institute of Pathogen Biology and Immunology of College of Biology, State Key Laboratory of Chemo/Biosensing and Chemometrics , Hunan University , Changsha 410082 , People's Republic of China
| | - Zhou Nie
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , People's Republic of China
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19
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RNA-Binding Motif Protein 24 (RBM24) Is Involved in Pregenomic RNA Packaging by Mediating Interaction between Hepatitis B Virus Polymerase and the Epsilon Element. J Virol 2019; 93:JVI.02161-18. [PMID: 30626666 DOI: 10.1128/jvi.02161-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 12/18/2018] [Indexed: 12/14/2022] Open
Abstract
Encapsidation of pregenomic RNA (pgRNA) is a crucial step in hepatitis B virus (HBV) replication. Binding by viral polymerase (Pol) to the epsilon stem-loop (ε) on the 5'-terminal region (TR) of pgRNA is required for pgRNA packaging. However, the detailed mechanism is not well understood. RNA-binding motif protein 24 (RBM24) inhibits core translation by binding to the 5'-TR of pgRNA. Here, we demonstrate that RBM24 is also involved in pgRNA packaging. RBM24 directly binds to the lower bulge of ε via RNA recognition submotifs (RNPs). RBM24 also interacts with Pol in an RNA-independent manner. The alanine-rich domain (ARD) of RBM24 and the reverse transcriptase (RT) domain of Pol are essential for binding between RBM24 and Pol. In addition, overexpression of RBM24 increases Pol-ε interaction, whereas RBM24 knockdown decreases the interaction. RBM24 was able to rescue binding between ε and mutant Pol lacking ε-binding activity, further showing that RBM24 mediates the interaction between Pol and ε by forming a Pol-RBM24-ε complex. Finally, RBM24 significantly promotes the packaging efficiency of pgRNA. In conclusion, RBM24 mediates Pol-ε interaction and formation of a Pol-RBM24-ε complex, which inhibits translation of pgRNA and results in pgRNA packing into capsids/virions for reverse transcription and DNA synthesis.IMPORTANCE Hepatitis B virus (HBV) is a ubiquitous human pathogen, and HBV infection is a major global health burden. Chronic HBV infection is associated with the development of liver diseases, including fulminant hepatitis, hepatic fibrosis, cirrhosis, and hepatocellular carcinoma. A currently approved vaccine can prevent HBV infection, and medications are able to reduce viral loads and prevent liver disease progression. However, current treatments rarely achieve a cure for chronic infection. Thus, it is important to gain insight into the mechanisms of HBV replication. In this study, we found that the host factor RBM24 is involved in pregenomic RNA (pgRNA) packaging and regulates HBV replication. These findings highlight a potential target for antiviral therapeutics of HBV infection.
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Knodel MM, Targett-Adams P, Grillo A, Herrmann E, Wittum G. Advanced Hepatitis C Virus Replication PDE Models within a Realistic Intracellular Geometric Environment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E513. [PMID: 30759770 PMCID: PMC6388173 DOI: 10.3390/ijerph16030513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/08/2019] [Accepted: 01/16/2019] [Indexed: 02/06/2023]
Abstract
The hepatitis C virus (HCV) RNA replication cycle is a dynamic intracellular process occurring in three-dimensional space (3D), which is difficult both to capture experimentally and to visualize conceptually. HCV-generated replication factories are housed within virus-induced intracellular structures termed membranous webs (MW), which are derived from the Endoplasmatic Reticulum (ER). Recently, we published 3D spatiotemporal resolved diffusion⁻reaction models of the HCV RNA replication cycle by means of surface partial differential equation (sPDE) descriptions. We distinguished between the basic components of the HCV RNA replication cycle, namely HCV RNA, non-structural viral proteins (NSPs), and a host factor. In particular, we evaluated the sPDE models upon realistic reconstructed intracellular compartments (ER/MW). In this paper, we propose a significant extension of the model based upon two additional parameters: different aggregate states of HCV RNA and NSPs, and population dynamics inspired diffusion and reaction coefficients instead of multilinear ones. The combination of both aspects enables realistic modeling of viral replication at all scales. Specifically, we describe a replication complex state consisting of HCV RNA together with a defined amount of NSPs. As a result of the combination of spatial resolution and different aggregate states, the new model mimics a cis requirement for HCV RNA replication. We used heuristic parameters for our simulations, which were run only on a subsection of the ER. Nevertheless, this was sufficient to allow the fitting of core aspects of virus reproduction, at least qualitatively. Our findings should help stimulate new model approaches and experimental directions for virology.
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Affiliation(s)
- Markus M Knodel
- Department of Mathematics, Chair of Applied Mathematics 1, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 11, 91058 Erlangen, Germany.
| | | | - Alfio Grillo
- Dipartimento di Scienze Matematiche (DISMA) "G.L. Lagrange", Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino (TO), Italy.
| | - Eva Herrmann
- Department of Medicine, Institute for Biostatistics and Mathematic Modeling, Goethe Universität Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Gabriel Wittum
- Goethe Center for Scientific Computing (G-CSC), Goethe Universität Frankfurt, Kettenhofweg 139, 60325 Frankfurt am Main, Germany.
- Applied Mathematics and Computational Science, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia.
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018. [PMID: 30564270 DOI: 10.3389/fgene.2018.00595/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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22
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018; 9:595. [PMID: 30564270 PMCID: PMC6288177 DOI: 10.3389/fgene.2018.00595] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/15/2018] [Indexed: 12/11/2022] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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23
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Banerjee S, Maurya S, Roy R. Single-molecule fluorescence imaging: Generating insights into molecular interactions in virology. J Biosci 2018; 43:519-540. [PMID: 30002270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Single-molecule fluorescence methods remain a challenging yet information-rich set of techniques that allow one to probe the dynamics, stoichiometry and conformation of biomolecules one molecule at a time. Viruses are small (nanometers) in size, can achieve cellular infections with a small number of virions and their lifecycle is inherently heterogeneous with a large number of structural and functional intermediates. Single-molecule measurements that reveal the complete distribution of properties rather than the average can hence reveal new insights into virus infections and biology that are inaccessible otherwise. This article highlights some of the methods and recent applications of single-molecule fluorescence in the field of virology. Here, we have focused on new findings in virus-cell interaction, virus cell entry and transport, viral membrane fusion, genome release, replication, translation, assembly, genome packaging, egress and interaction with host immune proteins that underline the advantage of single-molecule approach to the question at hand. Finally, we discuss the challenges, outlook and potential areas for improvement and future use of single-molecule fluorescence that could further aid our understanding of viruses.
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Affiliation(s)
- Sunaina Banerjee
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, India
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24
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Single-molecule fluorescence imaging: Generating insights into molecular interactions in virology. J Biosci 2018. [DOI: 10.1007/s12038-018-9769-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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25
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Grünvogel O, Colasanti O, Lee JY, Klöss V, Belouzard S, Reustle A, Esser-Nobis K, Hesebeck-Brinckmann J, Mutz P, Hoffmann K, Mehrabi A, Koschny R, Vondran FWR, Gotthardt D, Schnitzler P, Neumann-Haefelin C, Thimme R, Binder M, Bartenschlager R, Dubuisson J, Dalpke AH, Lohmann V. Secretion of Hepatitis C Virus Replication Intermediates Reduces Activation of Toll-Like Receptor 3 in Hepatocytes. Gastroenterology 2018. [PMID: 29535029 DOI: 10.1053/j.gastro.2018.03.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) infections most often result in chronic outcomes, although the virus constantly produces replication intermediates, in particular double-stranded RNA (dsRNA), representing potent inducers of innate immunity. We aimed to characterize the fate of HCV dsRNA in hepatocyte cultures to identify mechanisms contributing to viral persistence in presence of an active innate immune response. METHODS We analyzed hepatocyte-based culture models for HCV for induction of innate immunity, secretion of virus positive- or negative-strand RNA, and viral replication using different quantification methods and microscopy techniques. Expression of pattern recognition receptors was reconstituted in hepatoma cells by lentiviral transduction. RESULTS HCV-infected cells secrete substantial amounts of virus positive- and negative-strand RNAs in extracellular vesicles (EVs), toward the apical and basolateral domain of hepatocytes. Secretion of negative-strand RNA was independent from virus production, and viral RNA secreted in EVs contained higher relative amounts of negative-strands, indicating that mostly virus dsRNA is released. A substantial part of viral replication complexes and dsRNA was found in the endosomal compartment and multivesicular bodies, indicating that secretion of HCV replication intermediates is mediated by the exosomal pathway. Block of vesicle release in HCV-positive cells increased intracellular dsRNA levels and increased activation of toll-like receptor 3, inhibiting HCV replication. CONCLUSIONS Using hepatocyte-based culture models for HCV, we found a portion of HCV dsRNA intermediates to be released from infected cells in EVs, which reduces activation of toll-like receptor 3. This represents a novel mechanism how HCV evades host immune responses, potentially contributing to viral persistence.
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Affiliation(s)
- Oliver Grünvogel
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Ombretta Colasanti
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Ji-Young Lee
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Volker Klöss
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Heidelberg, Germany
| | - Sandrine Belouzard
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL- Centre d'Infection et d'Immunité de Lille, France
| | - Anna Reustle
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Katharina Esser-Nobis
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | | | - Pascal Mutz
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany; Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Katrin Hoffmann
- Department of General-, Visceral- and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Arianeb Mehrabi
- Department of General-, Visceral- and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Ronald Koschny
- Department of Gastroenterology, Infectious Diseases and Intoxication, University Hospital Heidelberg, Heidelberg, Germany
| | - Florian W R Vondran
- Regenerative Medicine and Experimental Surgery (ReMediES), Department of General, Visceral and Transplant Surgery, Hannover Medical School, Hannover, Germany; German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Hannover, Germany
| | - Daniel Gotthardt
- Department of Gastroenterology, Infectious Diseases and Intoxication, University Hospital Heidelberg, Heidelberg, Germany
| | - Paul Schnitzler
- Department of Infectious Diseases, Virology, University of Heidelberg, Heidelberg, Germany
| | - Christoph Neumann-Haefelin
- Department of Medicine II, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg
| | - Robert Thimme
- Department of Medicine II, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg
| | - Marco Binder
- Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany; Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jean Dubuisson
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL- Centre d'Infection et d'Immunité de Lille, France
| | - Alexander H Dalpke
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Heidelberg, Germany
| | - Volker Lohmann
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany.
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Cifuentes-Muñoz N, Branttie J, Slaughter KB, Dutch RE. Human Metapneumovirus Induces Formation of Inclusion Bodies for Efficient Genome Replication and Transcription. J Virol 2017; 91:e01282-17. [PMID: 28978704 PMCID: PMC5709606 DOI: 10.1128/jvi.01282-17] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/25/2017] [Indexed: 12/14/2022] Open
Abstract
Human metapneumovirus (HMPV) causes significant upper and lower respiratory disease in all age groups worldwide. The virus possesses a negative-sense single-stranded RNA genome of approximately 13.3 kb encapsidated by multiple copies of the nucleoprotein (N), giving rise to helical nucleocapsids. In addition, copies of the phosphoprotein (P) and the large RNA polymerase (L) decorate the viral nucleocapsids. After viral attachment, endocytosis, and fusion mediated by the viral glycoproteins, HMPV nucleocapsids are released into the cell cytoplasm. To visualize the subsequent steps of genome transcription and replication, a fluorescence in situ hybridization (FISH) protocol was established to detect different viral RNA subpopulations in infected cells. The FISH probes were specific for detection of HMPV positive-sense RNA (+RNA) and viral genomic RNA (vRNA). Time course analysis of human bronchial epithelial BEAS-2B cells infected with HMPV revealed the formation of inclusion bodies (IBs) from early times postinfection. HMPV IBs were shown to be cytoplasmic sites of active transcription and replication, with the translation of viral proteins being closely associated. Inclusion body formation was consistent with an actin-dependent coalescence of multiple early replicative sites. Time course quantitative reverse transcription-PCR analysis suggested that the coalescence of inclusion bodies is a strategy to efficiently replicate and transcribe the viral genome. These results provide a better understanding of the steps following HMPV entry and have important clinical implications.IMPORTANCE Human metapneumovirus (HMPV) is a recently discovered pathogen that affects human populations of all ages worldwide. Reinfections are common throughout life, but no vaccines or antiviral treatments are currently available. In this work, a spatiotemporal analysis of HMPV replication and transcription in bronchial epithelial cell-derived immortal cells was performed. HMPV was shown to induce the formation of large cytoplasmic granules, named inclusion bodies, for genome replication and transcription. Unlike other cytoplasmic structures, such as stress granules and processing bodies, inclusion bodies are exclusively present in infected cells and contain HMPV RNA and proteins to more efficiently transcribe and replicate the viral genome. Though inclusion body formation is nuanced, it corresponds to a more generalized strategy used by different viruses, including filoviruses and rhabdoviruses, for genome transcription and replication. Thus, an understanding of inclusion body formation is crucial for the discovery of innovative therapeutic targets.
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Affiliation(s)
- Nicolás Cifuentes-Muñoz
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Jean Branttie
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Kerri Beth Slaughter
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Rebecca Ellis Dutch
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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Garira W. A complete categorization of multiscale models of infectious disease systems. JOURNAL OF BIOLOGICAL DYNAMICS 2017; 11:378-435. [PMID: 28849734 DOI: 10.1080/17513758.2017.1367849] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Modelling of infectious disease systems has entered a new era in which disease modellers are increasingly turning to multiscale modelling to extend traditional modelling frameworks into new application areas and to achieve higher levels of detail and accuracy in characterizing infectious disease systems. In this paper we present a categorization framework for categorizing multiscale models of infectious disease systems. The categorization framework consists of five integration frameworks and five criteria. We use the categorization framework to give a complete categorization of host-level immuno-epidemiological models (HL-IEMs). This categorization framework is also shown to be applicable in categorizing other types of multiscale models of infectious diseases beyond HL-IEMs through modifying the initial categorization framework presented in this study. Categorization of multiscale models of infectious disease systems in this way is useful in bringing some order to the discussion on the structure of these multiscale models.
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Affiliation(s)
- Winston Garira
- a Modelling Health and Environmental Linkages Research Group (MHELRG), Department of Mathematics and Applied Mathematics , University of Venda , Thohoyandou, South Africa
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28
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Zhang X, Yue L, Zhang Z, Yuan Z. Establishment of a fluorescent in situ hybridization assay for imaging hepatitis B virus nucleic acids in cell culture models. Emerg Microbes Infect 2017; 6:e98. [PMID: 29116221 PMCID: PMC5717087 DOI: 10.1038/emi.2017.84] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 08/17/2017] [Accepted: 08/29/2017] [Indexed: 12/18/2022]
Abstract
While chronic hepatitis B remains a global public health problem, the detailed spatiotemporal dynamics of the key molecular events leading to the multiplication and egress of hepatitis B virus (HBV) are still largely unclear. Previously, we developed a chromogenic in situ hybridization assay for detection of HBV RNA, DNA and covalently closed circular DNA in clinical liver biopsies. Here, we report the establishment of a fluorescent in situ hybridization method for the visualization of HBV RNA, HBV core particle DNA and intranuclear DNA in a tetracycline-inducible HBV replication system (HepAD38) and a de novo infection system (HepG2-NTCP). Using 3D-STORM (three-dimensional stochastic optical reconstruction microscopy), we were able to obtain images of HBV RNA and DNA with improved spatial resolution allowing in-depth analyses of key virological events within complex subcellular compartments. Taken together, these techniques should facilitate a deeper understanding of the molecular events of the HBV life cycle and shed new light on the intricate mechanisms of virus-host interactions.
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Affiliation(s)
- Xiaonan Zhang
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Lei Yue
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China.,Key Laboratory of Medical Molecular Virology at School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhanqing Zhang
- Department of Hepatology, Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Zhenghong Yuan
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China.,Key Laboratory of Medical Molecular Virology at School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
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Romero-López C, Berzal-Herranz A. The 5BSL3.2 Functional RNA Domain Connects Distant Regions in the Hepatitis C Virus Genome. Front Microbiol 2017; 8:2093. [PMID: 29163393 PMCID: PMC5671509 DOI: 10.3389/fmicb.2017.02093] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/12/2017] [Indexed: 02/05/2023] Open
Abstract
Viral genomes are complexly folded entities that carry all the information required for the infective cycle. The nucleotide sequence of the RNA virus genome encodes proteins and functional information contained in discrete, highly conserved structural units. These so-called functional RNA domains play essential roles in the progression of infection, which requires their preservation from one generation to the next. Numerous functional RNA domains exist in the genome of the hepatitis C virus (HCV). Among them, the 5BSL3.2 domain in the cis-acting replication element (CRE) at the 3' end of the viral open reading frame has become of particular interest given its role in HCV RNA replication and as a regulator of viral protein synthesis. These functionalities are achieved via the establishment of a complex network of long-distance RNA-RNA contacts involving (at least as known to date) the highly conserved 3'X tail, the apical loop of domain IIId in the internal ribosome entry site, and/or the so-called Alt region upstream of the CRE. Changing contacts promotes the execution of different stages of the viral cycle. The 5BSL3.2 domain thus operates at the core of a system that governs the progression of HCV infection. This review summarizes our knowledge of the long-range RNA-RNA interaction network in the HCV genome, with special attention paid to the structural and functional consequences derived from the establishment of different contacts. The potential implications of such interactions in switching between the different stages of the viral cycle are discussed.
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Affiliation(s)
- Cristina Romero-López
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Granada, Spain
| | - Alfredo Berzal-Herranz
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Granada, Spain
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30
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Boson B, Denolly S, Turlure F, Chamot C, Dreux M, Cosset FL. Daclatasvir Prevents Hepatitis C Virus Infectivity by Blocking Transfer of the Viral Genome to Assembly Sites. Gastroenterology 2017; 152:895-907.e14. [PMID: 27932311 DOI: 10.1053/j.gastro.2016.11.047] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 11/15/2016] [Accepted: 11/28/2016] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Daclatasvir is a direct-acting antiviral agent and potent inhibitor of NS5A, which is involved in replication of the hepatitis C virus (HCV) genome, presumably via membranous web shaping, and assembly of new virions, likely via transfer of the HCV RNA genome to viral particle assembly sites. Daclatasvir inhibits the formation of new membranous web structures and, ultimately, of replication complex vesicles, but also inhibits an early assembly step. We investigated the relationship between daclatasvir-induced clustering of HCV proteins, intracellular localization of viral RNAs, and inhibition of viral particle assembly. METHODS Cell-culture-derived HCV particles were produced from Huh7.5 hepatocarcinoma cells in presence of daclatasvir for short time periods. Infectivity and production of physical particles were quantified and producer cells were subjected to subcellular fractionation. Intracellular colocalization between core, E2, NS5A, NS4B proteins, and viral RNAs was quantitatively analyzed by confocal microscopy and by structured illumination microscopy. RESULTS Short exposure of HCV-infected cells to daclatasvir reduced viral assembly and induced clustering of structural proteins with non-structural HCV proteins, including core, E2, NS4B, and NS5A. These clustered structures appeared to be inactive assembly platforms, likely owing to loss of functional connection with replication complexes. Daclatasvir greatly reduced delivery of viral genomes to these core clusters without altering HCV RNA colocalization with NS5A. In contrast, daclatasvir neither induced clustered structures nor inhibited HCV assembly in cells infected with a daclatasvir-resistant mutant (NS5A-Y93H), indicating that daclatasvir targets a mutual, specific function of NS5A inhibiting both processes. CONCLUSIONS In addition to inhibiting replication complex biogenesis, daclatasvir prevents viral assembly by blocking transfer of the viral genome to assembly sites. This leads to clustering of HCV proteins because viral particles and replication complex vesicles cannot form or egress. This dual mode of action of daclatasvir could explain its efficacy in blocking HCV replication in cultured cells and in treatment of patients with HCV infection.
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Affiliation(s)
- Bertrand Boson
- CIRI - International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Solène Denolly
- CIRI - International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Fanny Turlure
- CIRI - International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Christophe Chamot
- Plateau Technique Imagerie/Microcopie, Lyon Bio Image, SFR-BioSciences, ENS de Lyon, Inserm US8, CNRS UMS3444, UCBL, France
| | - Marlène Dreux
- CIRI - International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France
| | - François-Loïc Cosset
- CIRI - International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.
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31
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Wang H, Tai AW. Continuous de novo generation of spatially segregated hepatitis C virus replication organelles revealed by pulse-chase imaging. J Hepatol 2017; 66:55-66. [PMID: 27599826 PMCID: PMC5167665 DOI: 10.1016/j.jhep.2016.08.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 08/22/2016] [Accepted: 08/26/2016] [Indexed: 01/22/2023]
Abstract
BACKGROUND & AIMS Like all positive-sense RNA viruses, hepatitis C virus (HCV) induces host membrane alterations for its replication. In chronically infected cells, it is not known whether these viral replication organelles are being continually resupplied by newly synthesized viral proteins in situ, or whether they are generated de novo. Here we aimed to study temporal events in replication organelles formation and maturation. METHODS Here we use pulse-chase labeling in combination with confocal microscopy, correlative light electron microscopy and biochemical methods to identify temporally distinct populations of replication organelles in living cells and study the formation, morphogenesis as well as compositional and functional changes of replication organelles over time. RESULTS We found that HCV replication organelles are continuously generated de novo at spatially distinct sites from preformed ones. This process is accompanied by accumulated intracellular membrane alteration, increased cholesterol delivery, NS5A phosphorylation, and positive-strand RNA content, and by eventual association with HCV core protein around lipid droplets. Generation of spatially segregated foci requires viral NS5A and the host factors phosphatidylinositol 4-kinase and oxysterol-binding protein, while association of foci with lipid droplets requires cholesterol. CONCLUSIONS Our results reveal that HCV replication organelles are not static structures, but instead are continuously generated and dynamically change in composition and possibly also in function. LAY SUMMARY Hepatitis C virus replication membrane structures are continuously generated at spatially distinct sites. New replication organelles are different in composition, and possibly also in function, compared to old replication organelles.
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Affiliation(s)
- Hongliang Wang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Andrew W. Tai
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
,Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
,Medicine Service, Ann Arbor Veterans Administration Health System, Ann Arbor, Michigan
,Correspondence: Andrew W. Tai, University of Michigan, 6520 MSRB I SPC 5682, 1150 W Medical Center Dr, Ann Arbor, MI 48109-5682, Tel: (734) 764-2804, FAX: (734) 763-2535,
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32
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Bayer K, Banning C, Bruss V, Wiltzer-Bach L, Schindler M. Hepatitis C Virus Is Released via a Noncanonical Secretory Route. J Virol 2016; 90:10558-10573. [PMID: 27630244 PMCID: PMC5110177 DOI: 10.1128/jvi.01615-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 09/11/2016] [Indexed: 12/12/2022] Open
Abstract
We analyzed hepatitis C virus (HCV) morphogenesis using viral genomes encoding a mCherry-tagged E1 glycoprotein. HCV-E1-mCherry polyprotein expression, intracellular localization, and replication kinetics were comparable to those of untagged HCV, and E1-mCherry-tagged viral particles were assembled and released into cell culture supernatants. Expression and localization of structural E1 and nonstructural NS5A followed a temporospatial pattern with a succinct decrease in the number of replication complexes and the appearance of E1-mCherry punctae. Interaction of the structural proteins E1, Core, and E2 increased at E1-mCherry punctae in a time-dependent manner, indicating that E1-mCherry punctae represent assembled or assembling virions. E1-mCherry did not colocalize with Golgi markers. Furthermore, the bulk of viral glycoproteins within released particles revealed an EndoH-sensitive glycosylation pattern, indicating an absence of viral glycoprotein processing by the Golgi apparatus. In contrast, HCV-E1-mCherry trafficked with Rab9-positive compartments and inhibition of endosomes specifically suppressed HCV release. Our data suggest that assembled HCV particles are released via a noncanonical secretory route involving the endosomal compartment. IMPORTANCE The goal of this study was to shed light on the poorly understood trafficking and release routes of hepatitis C virus (HCV). For this, we generated novel HCV genomes which resulted in the production of fluorescently labeled viral particles. We used live-cell microscopy and other imaging techniques to follow up on the temporal dynamics of virus particle formation and trafficking in HCV-expressing liver cells. While viral particles and viral structural protein were found in endosomal compartments, no overlap of Golgi structures could be observed. Furthermore, biochemical and inhibitor-based experiments support a HCV release route which is distinguishable from canonical Golgi-mediated secretion. Since viruses hijack cellular pathways to generate viral progeny, our results point toward the possible existence of a not-yet-described cellular secretion route.
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Affiliation(s)
- Karen Bayer
- Institute of Virology, Helmholtz Zentrum München-German Research Center for Environmental Health, Munich, Germany
| | - Carina Banning
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Volker Bruss
- Institute of Virology, Helmholtz Zentrum München-German Research Center for Environmental Health, Munich, Germany
| | - Linda Wiltzer-Bach
- University Hospital Tübingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Tübingen, Germany
| | - Michael Schindler
- Institute of Virology, Helmholtz Zentrum München-German Research Center for Environmental Health, Munich, Germany
- University Hospital Tübingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Tübingen, Germany
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
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33
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Moradpour D, Grakoui A, Manns MP. Future landscape of hepatitis C research - Basic, translational and clinical perspectives. J Hepatol 2016; 65:S143-S155. [PMID: 27641984 DOI: 10.1016/j.jhep.2016.07.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 12/14/2022]
Abstract
With the latest all-oral interferon- and ribavirin-free regimens based on direct acting antivirals against the hepatitis C virus (HCV), sustained virological response rates of >90% are achieved, which is equivalent to cure. This has become possible for all genotypes and all subgroups of patients, including many of the most difficult-to-treat populations so far. Since a prophylactic HCV vaccine is not yet available, control of HCV infection will for the time being have to rely on the use of effective and safe antiviral treatments as well as their accessibility and affordability. Different approaches may apply to different parts of the world, eradication of HCV representing a major long-term goal. Whether hepatitis C becomes the first chronic viral infection to be eradicated without a prophylactic vaccine remains to be shown. Here, we briefly summarize advances in the molecular virology of hepatitis C, highlight lessons of biological relevance that were learned through the study of HCV, and its translational and clinical implications. We have also listed selected unsolved challenges, emphasizing that HCV is a unique model and that advances in this direction may yield knowledge of broad biological significance, novel technologies and insights into related important human pathogens.
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Affiliation(s)
- Darius Moradpour
- Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland.
| | - Arash Grakoui
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine and Yerkes National Primate Research Center, Emory Vaccine Center, Atlanta, GA, USA.
| | - Michael P Manns
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Germany; German Centre for Infection Research (DZIF), partner site Hannover-Braunschweig, Germany.
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34
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Abstract
The way in which a viral infection spreads within a host is a complex process that is not well understood. Different viruses, such as human immunodeficiency virus type 1 and hepatitis C virus, have evolved different strategies, including direct cell-to-cell transmission and cell-free transmission, to spread within a host. To what extent these two modes of transmission are exploited in vivo is still unknown. Mathematical modeling has been an essential tool to get a better systematic and quantitative understanding of viral processes that are difficult to discern through strictly experimental approaches. In this review, we discuss recent attempts that combine experimental data and mathematical modeling in order to determine and quantify viral transmission modes. We also discuss the current challenges for a systems-level understanding of viral spread, and we highlight the promises and challenges that novel experimental techniques and data will bring to the field.
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Affiliation(s)
- Frederik Graw
- Center for Modelling and Simulation in the Biosciences, BioQuant Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Alan S Perelson
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545;
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35
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Culley S, Towers GJ, Selwood DL, Henriques R, Grove J. Infection Counter: Automated Quantification of in Vitro Virus Replication by Fluorescence Microscopy. Viruses 2016; 8:v8070201. [PMID: 27455304 PMCID: PMC4974536 DOI: 10.3390/v8070201] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/01/2016] [Accepted: 07/05/2016] [Indexed: 01/24/2023] Open
Abstract
The ability to accurately and reliably quantify viral infection is essential to basic and translational virology research. Here, we describe a simple and robust automated method for using fluorescence microscopy to estimate the proportion of virally infected cells in a monolayer. We provide details of the automated analysis workflow along with a freely available open-source ImageJ plugin, Infection Counter, for performing image quantification. Using hepatitis C virus (HCV) as an example, we have experimentally verified our method, demonstrating that it is equivalent, if not better, than the established focus-forming assay. Finally, we used Infection Counter to assess the anti-HCV activity of SMBz-CsA, a non-immunosuppressive cyclosporine analogue.
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Affiliation(s)
- Siân Culley
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.
| | - Greg J Towers
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK.
| | - David L Selwood
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK.
| | - Ricardo Henriques
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.
| | - Joe Grove
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK.
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36
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Shulla A, Randall G. (+) RNA virus replication compartments: a safe home for (most) viral replication. Curr Opin Microbiol 2016; 32:82-88. [PMID: 27253151 PMCID: PMC4983521 DOI: 10.1016/j.mib.2016.05.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 12/19/2022]
Abstract
(+) RNA virus replication compartments form two structural classes. Both classes of replication compartments use cellular membrane curvature proteins. Both classes of replication compartments manipulate de novo lipid synthesis. Some double membrane vesicles use cellular lipid kinases and transfer proteins. Limited transient replication may occur before replication compartment formation.
This review describes recent advances in our understanding of the mechanisms by which (+) RNA viruses establish their replication niche.
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Affiliation(s)
- Ana Shulla
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States
| | - Glenn Randall
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States.
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37
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Wang H, Tai AW. Mechanisms of Cellular Membrane Reorganization to Support Hepatitis C Virus Replication. Viruses 2016; 8:v8050142. [PMID: 27213428 PMCID: PMC4885097 DOI: 10.3390/v8050142] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/20/2016] [Accepted: 05/15/2016] [Indexed: 12/13/2022] Open
Abstract
Like all positive-sense RNA viruses, hepatitis C virus (HCV) induces host membrane alterations for its replication termed the membranous web (MW). Assembling replication factors at a membranous structure might facilitate the processes necessary for genome replication and packaging and shield viral components from host innate immune defenses. The biogenesis of the HCV MW is a complex process involving a concerted effort of HCV nonstructural proteins with a growing list of host factors. Although a comprehensive understanding of MW formation is still missing, a number of important viral and host determinants have been identified. This review will summarize the recent studies that have led to our current knowledge of the role of viral and host factors in the biogenesis of the MWs and discuss how HCV uses this specialized membrane structure for its replication.
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Affiliation(s)
- Hongliang Wang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Andrew W Tai
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
- Medicine Service, Ann Arbor Veterans Administration Health System, Ann Arbor, MI 48105, USA.
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38
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Ramanan V, Trehan K, Ong ML, Luna JM, Hoffmann HH, Espiritu C, Sheahan TP, Chandrasekar H, Schwartz RE, Christine KS, Rice CM, van Oudenaarden A, Bhatia SN. Viral genome imaging of hepatitis C virus to probe heterogeneous viral infection and responses to antiviral therapies. Virology 2016; 494:236-47. [PMID: 27128351 DOI: 10.1016/j.virol.2016.04.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 12/12/2022]
Abstract
Hepatitis C virus (HCV) is a positive single-stranded RNA virus of enormous global health importance, with direct-acting antiviral therapies replacing an immunostimulatory interferon-based regimen. The dynamics of HCV positive and negative-strand viral RNAs (vRNAs) under antiviral perturbations have not been studied at the single-cell level, leaving a gap in our understanding of antiviral kinetics and host-virus interactions. Here, we demonstrate quantitative imaging of HCV genomes in multiple infection models, and multiplexing of positive and negative strand vRNAs and host antiviral RNAs. We capture the varying kinetics with which antiviral drugs with different mechanisms of action clear HCV infection, finding the NS5A inhibitor daclatasvir to induce a rapid decline in negative-strand viral RNAs. We also find that the induction of host antiviral genes upon interferon treatment is positively correlated with viral load in single cells. This study adds smFISH to the toolbox available for analyzing the treatment of RNA virus infections.
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Affiliation(s)
- Vyas Ramanan
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kartik Trehan
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Mei-Lyn Ong
- Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Joseph M Luna
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, 10065 NY, USA
| | - Hans-Heinrich Hoffmann
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, 10065 NY, USA
| | - Christine Espiritu
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, 10065 NY, USA
| | - Timothy P Sheahan
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, 10065 NY, USA
| | - Hamsika Chandrasekar
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert E Schwartz
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kathleen S Christine
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Charles M Rice
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, 10065 NY, USA
| | - Alexander van Oudenaarden
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Sangeeta N Bhatia
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Division of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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39
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HCV RNA traffic and association with NS5A in living cells. Virology 2016; 493:60-74. [PMID: 26999027 DOI: 10.1016/j.virol.2016.02.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/11/2016] [Accepted: 02/18/2016] [Indexed: 01/05/2023]
Abstract
The spatiotemporal dynamics of Hepatitis C Virus (HCV) RNA localisation are poorly understood. To address this we engineered HCV genomes harbouring MS2 bacteriophage RNA stem-loops within the 3'-untranslated region to allow tracking of HCV RNA via specific interaction with a MS2-Coat-mCherry fusion protein. Despite the impact of these insertions on viral fitness, live imaging revealed that replication of tagged-HCV genomes induced specific redistribution of the mCherry-tagged-MS2-Coat protein to motile and static foci. Further analysis showed that HCV RNA was associated with NS5A in both static and motile structures while a subset of motile NS5A structures was devoid of HCV RNA. Further investigation of viral RNA traffic with respect to lipid droplets (LDs) revealed HCV RNA-positive structures in close association with LDs. These studies provide new insights into the dynamics of HCV RNA traffic with NS5A and LDs and provide a platform for future investigations of HCV replication and assembly.
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40
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Kumberger P, Frey F, Schwarz US, Graw F. Multiscale modeling of virus replication and spread. FEBS Lett 2016; 590:1972-86. [PMID: 26878104 DOI: 10.1002/1873-3468.12095] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 01/21/2016] [Accepted: 02/07/2016] [Indexed: 01/16/2023]
Abstract
Replication and spread of human viruses is based on the simultaneous exploitation of many different host functions, bridging multiple scales in space and time. Mathematical modeling is essential to obtain a systems-level understanding of how human viruses manage to proceed through their life cycles. Here, we review corresponding advances for viral systems of large medical relevance, such as human immunodeficiency virus-1 (HIV-1) and hepatitis C virus (HCV). We will outline how the combination of mathematical models and experimental data has advanced our quantitative knowledge about various processes of these pathogens, and how novel quantitative approaches promise to fill remaining gaps.
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Affiliation(s)
- Peter Kumberger
- BioQuant-Center, Heidelberg University, Germany.,Center for Modeling and Simulation in the Biosciences (BIOMS), Heidelberg University, Germany
| | - Felix Frey
- BioQuant-Center, Heidelberg University, Germany.,Institute for Theoretical Physics, Heidelberg University, Germany
| | - Ulrich S Schwarz
- BioQuant-Center, Heidelberg University, Germany.,Institute for Theoretical Physics, Heidelberg University, Germany
| | - Frederik Graw
- BioQuant-Center, Heidelberg University, Germany.,Center for Modeling and Simulation in the Biosciences (BIOMS), Heidelberg University, Germany
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41
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Neufeldt CJ, Joyce MA, Van Buuren N, Levin A, Kirkegaard K, Gale Jr. M, Tyrrell DLJ, Wozniak RW. The Hepatitis C Virus-Induced Membranous Web and Associated Nuclear Transport Machinery Limit Access of Pattern Recognition Receptors to Viral Replication Sites. PLoS Pathog 2016; 12:e1005428. [PMID: 26863439 PMCID: PMC4749181 DOI: 10.1371/journal.ppat.1005428] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 01/10/2016] [Indexed: 12/25/2022] Open
Abstract
Hepatitis C virus (HCV) is a positive-strand RNA virus of the Flaviviridae family and a major cause of liver disease worldwide. HCV replicates in the cytoplasm, and the synthesis of viral proteins induces extensive rearrangements of host cell membranes producing structures, collectively termed the membranous web (MW). The MW contains the sites of viral replication and assembly, and we have identified distinct membrane fractions derived from HCV-infected cells that contain replication and assembly complexes enriched for viral RNA and infectious virus, respectively. The complex membrane structure of the MW is thought to protect the viral genome limiting its interactions with cytoplasmic pattern recognition receptors (PRRs) and thereby preventing activation of cellular innate immune responses. Here we show that PRRs, including RIG-I and MDA5, and ribosomes are excluded from viral replication and assembly centers within the MW. Furthermore, we present evidence that components of the nuclear transport machinery regulate access of proteins to MW compartments. We show that the restricted assess of RIG-I to the MW can be overcome by the addition of a nuclear localization signal sequence, and that expression of a NLS-RIG-I construct leads to increased immune activation and the inhibition of viral replication. Hepatitis C virus (HCV) is a positive-strand RNA virus and it is a major cause of liver disease worldwide affecting more than 170 million individuals. Infection of cells with HCV leads to rearrangement of cytoplasmic host cell membranes and the formation of the membranous web (MW) containing viral replication and assembly complexes. The MW is thought to function in concentrating viral components, regulating virus replication, and immune evasion. Our analysis has provided new insight into the organization of the MW and the mechanisms that contribute to the formation and maintenance of distinct compartments within the MW. We show that the MW limits access of host cell innate immune receptors to sites of viral replication and assembly. Moreover, we show that components of the nuclear transport machinery, normally involved in regulating traffic between the cytoplasm and the nucleus, have a role in limiting immune receptor access to compartments within the MW. These findings provide important insights in how HCV, and likely other positive-strand RNA viruses, organize their replication factories and evaded recognition by host cell immune receptors.
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Affiliation(s)
- Christopher J. Neufeldt
- Department of Cell Biology University of Alberta, Edmonton, Alberta, Canada
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Edmonton, Alberta, Canada
| | - Michael A. Joyce
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Edmonton, Alberta, Canada
| | - Nicholas Van Buuren
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Aviad Levin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Edmonton, Alberta, Canada
| | - Karla Kirkegaard
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Michael Gale Jr.
- Department of Immunology, University of Washington, Seattle, Washington, United States of America
| | - D. Lorne J. Tyrrell
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Edmonton, Alberta, Canada
- * E-mail: (RWW); (DLJT)
| | - Richard W. Wozniak
- Department of Cell Biology University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Edmonton, Alberta, Canada
- * E-mail: (RWW); (DLJT)
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42
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Y-Box Binding Protein 1 Stabilizes Hepatitis C Virus NS5A via Phosphorylation-Mediated Interaction with NS5A To Regulate Viral Propagation. J Virol 2015; 89:11584-602. [PMID: 26355086 DOI: 10.1128/jvi.01513-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/01/2015] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Replication of hepatitis C virus (HCV) is dependent on virus-encoded proteins and numerous cellular factors. DDX3 is a well-known host cofactor of HCV replication. In this study, we investigated the role of a DDX3-interacting protein, Y-box binding protein 1 (YB-1), in the HCV life cycle. Both YB-1 and DDX3 interacted with the viral nonstructural protein NS5A. During HCV infection, YB-1 partially colocalized with NS5A and the HCV replication intermediate double-stranded RNA (dsRNA) in HCV-infected Huh-7.5.1 cells. Despite sharing the same interacting partners, YB-1 participated in HCV RNA replication but was dispensable in steady-state HCV RNA replication, different from the action of DDX3. Moreover, knockdown of YB-1 in HCV-infected cells prevented infectious virus production and reduced the ratio of hyperphosphorylated (p58) to hypophosphorylated (p56) forms of NS5A, whereas DDX3 silencing did not affect the ratio of the p58 and p56 phosphoforms of NS5A. Interestingly, silencing of YB-1 severely reduced NS5A protein stability in NS5A-ectopically expressing, replicon-containing, and HCV-infected cells. Furthermore, mutations of serine 102 of YB-1 affected both YB-1-NS5A interaction and NS5A-stabilizing activity of YB-1, indicating that this Akt phosphorylation site of YB-1 plays an important role in stabilizing NS5A. Collectively, our results support a model in which the event of YB-1 phosphorylation-mediated interaction with NS5A results in stabilizing NS5A to sustain HCV RNA replication and infectious HCV production. Overall, our study may reveal a new aspect for the development of novel anti-HCV drugs. IMPORTANCE Chronic hepatitis C virus (HCV) infection induces liver cirrhosis and hepatocellular carcinoma. The viral nonstructural protein NS5A co-opting various cellular signaling pathways and cofactors to support viral genome replication and virion assembly is a new strategy for anti-HCV drug development. NS5A phosphorylation is believed to modulate switches between different stages of the HCV life cycle. In this study, we identified the cellular protein YB-1 as a novel NS5A-interacting protein. YB-1 is a multifunctional protein participating in oncogenesis and is an oncomarker of hepatocellular carcinoma (HCC). We found that YB-1 protects NS5A from degradation and likely regulates NS5A phosphorylation through its phosphorylation-dependent interaction with NS5A, which might be controlled by HCV-induced signaling pathways. Our observations suggest a model in which HCV modulates NS5A level and the ratio of the p58 and p56 phosphoforms for efficient viral propagation via regulation of cellular signaling inducing YB-1 phosphorylation. Our finding may provide new aspects for developing novel anti-HCV drugs.
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