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Soper N, Yardumian I, Chen E, Yang C, Ciervo S, Oom AL, Desvignes L, Mulligan MJ, Zhang Y, Lupoli TJ. A Repurposed Drug Interferes with Nucleic Acid to Inhibit the Dual Activities of Coronavirus Nsp13. ACS Chem Biol 2024; 19:1593-1603. [PMID: 38980755 DOI: 10.1021/acschembio.4c00244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
The recent pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) highlighted a critical need to discover more effective antivirals. While therapeutics for SARS-CoV-2 exist, its nonstructural protein 13 (Nsp13) remains a clinically untapped target. Nsp13 is a helicase responsible for unwinding double-stranded RNA during viral replication and is essential for propagation. Like other helicases, Nsp13 has two active sites: a nucleotide binding site that hydrolyzes nucleoside triphosphates (NTPs) and a nucleic acid binding channel that unwinds double-stranded RNA or DNA. Targeting viral helicases with small molecules, as well as the identification of ligand binding pockets, have been ongoing challenges, partly due to the flexible nature of these proteins. Here, we use a virtual screen to identify ligands of Nsp13 from a collection of clinically used drugs. We find that a known ion channel inhibitor, IOWH-032, inhibits the dual ATPase and helicase activities of SARS-CoV-2 Nsp13 at low micromolar concentrations. Kinetic and binding assays, along with computational and mutational analyses, indicate that IOWH-032 interacts with the RNA binding interface, leading to displacement of nucleic acid substrate, but not bound ATP. Evaluation of IOWH-032 with microbial helicases from other superfamilies reveals that it is selective for coronavirus Nsp13. Furthermore, it remains active against mutants representative of observed SARS-CoV-2 variants. Overall, this work provides a new inhibitor for Nsp13 and provides a rationale for a recent observation that IOWH-032 lowers SARS-CoV-2 viral loads in human cells, setting the stage for the discovery of other potent viral helicase modulators.
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Affiliation(s)
- Nathan Soper
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Isabelle Yardumian
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Eric Chen
- Department of Chemistry, New York University, New York, New York 10003, United States
- Simons Center for Computational Physical Chemistry at New York University, New York, New York 10003, United States
| | - Chao Yang
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Samantha Ciervo
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Aaron L Oom
- NYU Langone Vaccine Center, Department of Medicine, New York University Grossman School of Medicine, New York, New York 10016, United States
| | - Ludovic Desvignes
- NYU Langone Vaccine Center, Department of Medicine, New York University Grossman School of Medicine, New York, New York 10016, United States
- High Containment Laboratories, Office of Science and Research, NYU Langone Health, New York, New York 10016, United States
| | - Mark J Mulligan
- NYU Langone Vaccine Center, Department of Medicine, New York University Grossman School of Medicine, New York, New York 10016, United States
| | - Yingkai Zhang
- Department of Chemistry, New York University, New York, New York 10003, United States
- Simons Center for Computational Physical Chemistry at New York University, New York, New York 10003, United States
| | - Tania J Lupoli
- Department of Chemistry, New York University, New York, New York 10003, United States
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2
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Cloherty APM, Rader AG, Patel KS, Eisden TJTHD, van Piggelen S, Schreurs RRCE, Ribeiro CMS. Dengue virus exploits autophagy vesicles and secretory pathways to promote transmission by human dendritic cells. Front Immunol 2024; 15:1260439. [PMID: 38863700 PMCID: PMC11165123 DOI: 10.3389/fimmu.2024.1260439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 04/19/2024] [Indexed: 06/13/2024] Open
Abstract
Dengue virus (DENV), transmitted by infected mosquitoes, is a major public health concern, with approximately half the world's population at risk for infection. Recent decades have increasing incidence of dengue-associated disease alongside growing frequency of outbreaks. Although promising progress has been made in anti-DENV immunizations, post-infection treatment remains limited to non-specific supportive treatments. Development of antiviral therapeutics is thus required to limit DENV dissemination in humans and to help control the severity of outbreaks. Dendritic cells (DCs) are amongst the first cells to encounter DENV upon injection into the human skin mucosa, and thereafter promote systemic viral dissemination to additional human target cells. Autophagy is a vesicle trafficking pathway involving the formation of cytosolic autophagosomes, and recent reports have highlighted the extensive manipulation of autophagy by flaviviruses, including DENV, for viral replication. However, the temporal profiling and function of autophagy activity in DENV infection and transmission by human primary DCs remains poorly understood. Herein, we demonstrate that mechanisms of autophagosome formation and extracellular vesicle (EV) release have a pro-viral role in DC-mediated DENV transmission. We show that DENV exploits early-stage canonical autophagy to establish infection in primary human DCs. DENV replication enhanced autophagosome formation in primary human DCs, and intrinsically-heightened autophagosome biogenesis correlated with relatively higher rates of DC susceptibility to DENV. Furthermore, our data suggest that viral replication intermediates co-localize with autophagosomes, while productive DENV infection introduces a block at the late degradative stages of autophagy in infected DCs but not in uninfected bystander cells. Notably, we identify for the first time that approximately one-fourth of DC-derived CD9/CD81/CD63+ EVs co-express canonical autophagy marker LC3, and demonstrate that DC-derived EV populations are an alternative, cell-free mechanism by which DCs promote DENV transmission to additional target sites. Taken together, our study highlights intersections between autophagy and secretory pathways during viral infection, and puts forward autophagosome accumulation and viral RNA-laden EVs as host determinants of DC-mediated DENV infection in humans. Host-directed therapeutics targeting autophagy and exocytosis pathways thus have potential to enhance DC-driven resistance to DENV acquisition and thereby limit viral dissemination by initial human target cells following mosquito-to-human transmission of DENV.
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Affiliation(s)
- Alexandra P. M. Cloherty
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, Netherlands
| | - Anusca G. Rader
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, Netherlands
| | - Kharishma S. Patel
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, Netherlands
| | - Tracy-Jane T. H. D. Eisden
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, Netherlands
- Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Sterre van Piggelen
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, Netherlands
| | - Renée R. C. E. Schreurs
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, Netherlands
| | - Carla M. S. Ribeiro
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Institute for Immunology and Infectious Diseases, Amsterdam, Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, Netherlands
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3
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Mallya S, Pissurlenkar RRS. In-silico Investigations for the Identification of Novel Inhibitors Targeting Hepatitis C Virus RNA-dependent RNA Polymerase. Med Chem 2024; 20:52-62. [PMID: 37815178 DOI: 10.2174/0115734064255683230919071808] [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: 04/28/2023] [Revised: 08/11/2023] [Accepted: 08/22/2023] [Indexed: 10/11/2023]
Abstract
BACKGROUND Hepatitis C is an inflammatory condition of the liver caused by the hepatitis C virus, exhibiting acute and chronic manifestations with severity ranging from mild to severe and lifelong illnesses leading to liver cirrhosis and cancer. According to the World Health Organization's global estimates, a population of about 58 million have chronic hepatitis C virus infection, with around 1.5 million new infections occurring every year. OBJECTIVE The present study aimed to identify novel molecules targeting the Hepatitis C viral RNA Dependent RNA polymerases, which play a crucial role in genome replication, mRNA synthesis, etc. Methods: Structure-based virtual screening of chemical libraries of small molecules was done using AutoDock/Vina. The top-ranking pose for every ligand was complexed with the protein and used for further protein-ligand interaction analysis using the Protein-ligand interaction Profiler. Molecules from virtual screening were further assessed using the pkCSM web server. The proteinligand interactions were further subjected to molecular dynamics simulation studies to establish dynamic stability. RESULTS Molecular docking-based virtual screening of the database of small molecules, followed by screening based on pharmacokinetic and toxicity parameters, yielded eight probable RNA Dependent RNA polymerase inhibitors. The docking scores for the proposed candidates ranged from - 8.04 to -9.10 kcal/mol. The potential stability of the ligands bound to the target protein was demonstrated by molecular dynamics simulation studies. CONCLUSION Data from exhaustive computational studies proposed eight molecules as potential anti-viral candidates, targeting Hepatitis C viral RNA Dependent RNA polymerases, which can be further evaluated for their biological potential.
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Affiliation(s)
- Shailaja Mallya
- Department of Pharmacology, Goa College of Pharmacy, Panaji Goa, 403001 India
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Qu Y, Wang W, Xiao MZX, Zheng Y, Liang Q. The interplay between lipid droplets and virus infection. J Med Virol 2023; 95:e28967. [PMID: 37496184 DOI: 10.1002/jmv.28967] [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: 05/31/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/28/2023]
Abstract
As an intracellular parasite, the virus usurps cellular machinery and modulates cellular metabolism pathways to replicate itself in cells. Lipid droplets (LDs) are universally conserved energy storage organelles that not only play vital roles in maintaining lipid homeostasis but are also involved in viral replication. Increasing evidence has demonstrated that viruses take advantage of cellular lipid metabolism by targeting the biogenesis, hydrolysis, and lipophagy of LD during viral infection. In this review, we summarize the current knowledge about the modulation of cellular LD by different viruses, with a special emphasis on the Hepatitis C virus, Dengue virus, and SARS-CoV-2.
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Affiliation(s)
- Yafei Qu
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weili Wang
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Maggie Z X Xiao
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Yuejuan Zheng
- The Research Center for Traditional Chinese Medicine, Shanghai Institute of Infectious Disease and Biosecurity, Shanghai University of Traditional Medicine, Shanghai, China
- Center for Traditional Chinese Medicine and Immunology Research, School of Basic Medical Sciences, Shanghai University of Traditional Medicine, Shanghai, China
| | - Qiming Liang
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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5
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Pham MT, Lee JY, Ritter C, Thielemann R, Meyer J, Haselmann U, Funaya C, Laketa V, Rohr K, Bartenschlager R. Endosomal egress and intercellular transmission of hepatic ApoE-containing lipoproteins and its exploitation by the hepatitis C virus. PLoS Pathog 2023; 19:e1011052. [PMID: 37506130 PMCID: PMC10411793 DOI: 10.1371/journal.ppat.1011052] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 08/09/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Liver-generated plasma Apolipoprotein E (ApoE)-containing lipoproteins (LPs) (ApoE-LPs) play central roles in lipid transport and metabolism. Perturbations of ApoE can result in several metabolic disorders and ApoE genotypes have been associated with multiple diseases. ApoE is synthesized at the endoplasmic reticulum and transported to the Golgi apparatus for LP assembly; however, the ApoE-LPs transport pathway from there to the plasma membrane is largely unknown. Here, we established an integrative imaging approach based on a fully functional fluorescently tagged ApoE. We found that newly synthesized ApoE-LPs accumulate in CD63-positive endosomes of hepatocytes. In addition, we observed the co-egress of ApoE-LPs and CD63-positive intraluminal vesicles (ILVs), which are precursors of extracellular vesicles (EVs), along the late endosomal trafficking route in a microtubule-dependent manner. A fraction of ApoE-LPs associated with CD63-positive EVs appears to be co-transmitted from cell to cell. Given the important role of ApoE in viral infections, we employed as well-studied model the hepatitis C virus (HCV) and found that the viral replicase component nonstructural protein 5A (NS5A) is enriched in ApoE-containing ILVs. Interaction between NS5A and ApoE is required for the efficient release of ILVs containing HCV RNA. These vesicles are transported along the endosomal ApoE egress pathway. Taken together, our data argue for endosomal egress and transmission of hepatic ApoE-LPs, a pathway that is hijacked by HCV. Given the more general role of EV-mediated cell-to-cell communication, these insights provide new starting points for research into the pathophysiology of ApoE-related metabolic and infection-related disorders.
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Affiliation(s)
- Minh-Tu Pham
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Diseases Research, Heidelberg University, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Ji-Young Lee
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Diseases Research, Heidelberg University, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Christian Ritter
- BioQuant Center, IPMB, Biomedical Computer Vision Group, Heidelberg University, Heidelberg, Germany
| | - Roman Thielemann
- BioQuant Center, IPMB, Biomedical Computer Vision Group, Heidelberg University, Heidelberg, Germany
| | - Janis Meyer
- BioQuant Center, IPMB, Biomedical Computer Vision Group, Heidelberg University, Heidelberg, Germany
| | - Uta Haselmann
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Diseases Research, Heidelberg University, Heidelberg, Germany
| | - Charlotta Funaya
- Electron Microscopy Core Facility (EMCF), Heidelberg University, Heidelberg, Germany
| | - Vibor Laketa
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
- Department of Infectious Diseases, Virology, Center for Integrative Infectious Diseases Research, Heidelberg University, Heidelberg, Germany
| | - Karl Rohr
- BioQuant Center, IPMB, Biomedical Computer Vision Group, Heidelberg University, Heidelberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Diseases Research, Heidelberg University, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
- Division Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
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6
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Chen S, Harris M. NS5A domain I antagonises PKR to facilitate the assembly of infectious hepatitis C virus particles. PLoS Pathog 2023; 19:e1010812. [PMID: 36795772 PMCID: PMC9977016 DOI: 10.1371/journal.ppat.1010812] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 03/01/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Hepatitis C virus NS5A is a multifunctional phosphoprotein comprised of three domains (DI, DII and DIII). DI and DII have been shown to function in genome replication, whereas DIII has a role in virus assembly. We previously demonstrated that DI in genotype 2a (JFH1) also plays a role in virus assembly, exemplified by the P145A mutant which blocked infectious virus production. Here we extend this analysis to identify two other conserved and surface exposed residues proximal to P145 (C142 and E191) that exhibited no defect in genome replication but impaired virus production. Further analysis revealed changes in the abundance of dsRNA, the size and distribution of lipid droplets (LD) and the co-localisation between NS5A and LDs in cells infected with these mutants, compared to wildtype. In parallel, to investigate the mechanism(s) underpinning this role of DI, we assessed the involvement of the interferon-induced double-stranded RNA-dependent protein kinase (PKR). In PKR-silenced cells, C142A and E191A exhibited levels of infectious virus production, LD size and co-localisation between NS5A and LD that were indistinguishable from wildtype. Co-immunoprecipitation and in vitro pulldown experiments confirmed that wildtype NS5A domain I (but not C142A or E191A) interacted with PKR. We further showed that the assembly phenotype of C142A and E191A was restored by ablation of interferon regulatory factor-1 (IRF1), a downstream effector of PKR. These data suggest a novel interaction between NS5A DI and PKR that functions to evade an antiviral pathway that blocks virus assembly through IRF1.
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Affiliation(s)
- Shucheng Chen
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, 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, United Kingdom
- * E-mail:
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7
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Ren J, Vaid TM, Lee H, Ojeda I, Johnson ME. Evaluation of interactions between the hepatitis C virus NS3/4A and sulfonamidobenzamide based molecules using molecular docking, molecular dynamics simulations and binding free energy calculations. J Comput Aided Mol Des 2023; 37:53-65. [PMID: 36427108 PMCID: PMC9839505 DOI: 10.1007/s10822-022-00490-1] [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: 08/20/2022] [Accepted: 11/17/2022] [Indexed: 11/26/2022]
Abstract
The Hepatitis C Virus (HCV) NS3/4A is an attractive target for the treatment of Hepatitis C infection. Herein, we present an investigation of HCV NS3/4A inhibitors based on a sulfonamidobenzamide scaffold. Inhibitor interactions with HCV NS3/4A were explored by molecular docking, molecular dynamics simulations, and MM/PBSA binding free energy calculations. All of the inhibitors adopt similar molecular docking poses in the catalytic site of the protease that are stabilized by hydrogen bond interactions with G137 and the catalytic S139, which are known to be important for potency and binding stability. The quantitative assessments of binding free energies from MM/PBSA correlate well with the experimental results, with a high coefficient of determination, R2 of 0.92. Binding free energy decomposition analyses elucidate the different contributions of Q41, F43, H57, R109, K136, G137, S138, S139, A156, M485, and Q526 in binding different inhibitors. The importance of these sidechain contributions was further confirmed by computational alanine scanning mutagenesis. In addition, the sidechains of K136 and S139 show crucial but distinct contributions to inhibitor binding with HCV NS3/4A. The structural basis of the potency has been elucidated, demonstrating the importance of the R155 sidechain conformation. This extensive exploration of binding energies and interactions between these compounds and HCV NS3/4A at the atomic level should benefit future antiviral drug design.
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Affiliation(s)
- Jinhong Ren
- Center for Biomolecular Sciences and Department of Pharmaceutical Sciences, University of Illinois at Chicago, 900 S. Ashland Ave, Chicago, IL, 60607, USA
- BeiGene (Beijing) Co., Ltd, No. 30 Science Park Road, Zhong-Guan-Cun Life Sciences Park, Changping District, Beijing, 102206, People's Republic of China
| | - Tasneem M Vaid
- Center for Biomolecular Sciences and Department of Pharmaceutical Sciences, University of Illinois at Chicago, 900 S. Ashland Ave, Chicago, IL, 60607, USA
| | - Hyun Lee
- Center for Biomolecular Sciences and Department of Pharmaceutical Sciences, University of Illinois at Chicago, 900 S. Ashland Ave, Chicago, IL, 60607, USA
- Biophysics Core at Research Resource Center, University of Illinois at Chicago, 1100 S. Ashland Ave, Chicago, IL, 60607, USA
| | - Isabel Ojeda
- Center for Biomolecular Sciences and Department of Pharmaceutical Sciences, University of Illinois at Chicago, 900 S. Ashland Ave, Chicago, IL, 60607, USA
| | - Michael E Johnson
- Center for Biomolecular Sciences and Department of Pharmaceutical Sciences, University of Illinois at Chicago, 900 S. Ashland Ave, Chicago, IL, 60607, USA.
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8
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den Boon JA, Zhan H, Unchwaniwala N, Horswill M, Slavik K, Pennington J, Navine A, Ahlquist P. Multifunctional Protein A Is the Only Viral Protein Required for Nodavirus RNA Replication Crown Formation. Viruses 2022; 14:v14122711. [PMID: 36560715 PMCID: PMC9788154 DOI: 10.3390/v14122711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
Positive-strand RNA virus RNA genome replication occurs in membrane-associated RNA replication complexes (RCs). Nodavirus RCs are outer mitochondrial membrane invaginations whose necked openings to the cytosol are "crowned" by a 12-fold symmetrical proteinaceous ring that functions as the main engine of RNA replication. Similar protein crowns recently visualized at the openings of alphavirus and coronavirus RCs highlight their broad conservation and functional importance. Using cryo-EM tomography, we earlier showed that the major nodavirus crown constituent is viral protein A, whose polymerase, RNA capping, membrane interaction and multimerization domains drive RC formation and function. Other viral proteins are strong candidates for unassigned EM density in the crown. RNA-binding RNAi inhibitor protein B2 co-immunoprecipitates with protein A and could form crown subdomains that protect nascent viral RNA and dsRNA templates. Capsid protein may interact with the crown since nodavirus virion assembly has spatial and other links to RNA replication. Using cryoelectron tomography and complementary approaches, we show that, even when formed in mammalian cells, nodavirus RC crowns generated without B2 and capsid proteins are functional and structurally indistinguishable from mature crowns in infected Drosophila cells expressing all viral proteins. Thus, the only nodaviral factors essential to form functional RCs and crowns are RNA replication protein A and an RNA template. We also resolve apparent conflicts in prior results on B2 localization in infected cells, revealing at least two distinguishable pools of B2. The results have significant implications for crown structure, assembly, function and control as an antiviral target.
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Affiliation(s)
- Johan A. den Boon
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
- McArdle Laboratory for Cancer Research, University of Wisconsin–Madison, Madison, WI 53705, USA
| | - Hong Zhan
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Nuruddin Unchwaniwala
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Mark Horswill
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
- McArdle Laboratory for Cancer Research, University of Wisconsin–Madison, Madison, WI 53705, USA
| | - Kailey Slavik
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Janice Pennington
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Amanda Navine
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Paul Ahlquist
- John W. and Jeanne M. Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI 53715, USA
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, WI 53706, USA
- McArdle Laboratory for Cancer Research, University of Wisconsin–Madison, Madison, WI 53705, USA
- Correspondence:
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9
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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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10
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Prasad V, Bartenschlager R. A snapshot of protein trafficking in SARS-CoV-2 infection. Biol Cell 2022; 115:e2200073. [PMID: 36314261 PMCID: PMC9874443 DOI: 10.1111/boc.202200073] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/27/2022] [Accepted: 10/13/2022] [Indexed: 02/07/2023]
Abstract
SARS-CoV-2 is a human pathogenic virus responsible for the COVID-19 (coronavirus disease 2019) pandemic. The infection cycle of SARS-CoV-2 involves several related steps, including virus entry, gene expression, RNA replication, assembly of infectious virions and their egress. For all of these steps, the virus relies on and exploits host cell factors, cellular organelles, and processes such as endocytosis, nuclear transport, protein secretion, metabolite transport at membrane contact sites (MSC) and exocytotic pathways. To do this, SARS-CoV-2 has evolved multifunctional viral proteins that hijack cellular factors and modulate their function by unique strategies. In this Review, we highlight cellular trafficking factors, processes, and organelles of relevance to the SARS-CoV-2 infection cycle and how viral proteins make use of and perturb cellular transport during the viral infection cycle.
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Affiliation(s)
- Vibhu Prasad
- Department of Infectious DiseasesMolecular VirologyHeidelberg UniversityHeidelbergGermany
| | - Ralf Bartenschlager
- Department of Infectious DiseasesMolecular VirologyHeidelberg UniversityHeidelbergGermany,Division Virus‐Associated CarcinogenesisGerman Cancer Research CenterHeidelbergGermany,German Center for Infection ResearchHeidelberg Partner SiteHeidelbergGermany
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11
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Wang X, Zhu J, Zhang D, Liu G. Ribosomal control in RNA virus-infected cells. Front Microbiol 2022; 13:1026887. [PMID: 36419416 PMCID: PMC9677555 DOI: 10.3389/fmicb.2022.1026887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2022] Open
Abstract
Viruses are strictly intracellular parasites requiring host cellular functions to complete their reproduction cycle involving virus infection of host cell, viral genome replication, viral protein translation, and virion release. Ribosomes are protein synthesis factories in cells, and viruses need to manipulate ribosomes to complete their protein synthesis. Viruses use translation initiation factors through their own RNA structures or cap structures, thereby inducing ribosomes to synthesize viral proteins. Viruses also affect ribosome production and the assembly of mature ribosomes, and regulate the recognition of mRNA by ribosomes, thereby promoting viral protein synthesis and inhibiting the synthesis of host antiviral immune proteins. Here, we review the remarkable mechanisms used by RNA viruses to regulate ribosomes, in particular, the mechanisms by which RNA viruses induce the formation of specific heterogeneous ribosomes required for viral protein translation. This review provides valuable insights into the control of viral infection and diseases from the perspective of viral protein synthesis.
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12
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Zhou S, Fu Z, Zhang Z, Jia X, Xu G, Sun L, Sun F, Gao P, Xu P, Deng H. Liquid-liquid phase separation mediates the formation of herpesvirus assembly compartments. J Biophys Biochem Cytol 2022; 222:213550. [PMID: 36250941 PMCID: PMC9579985 DOI: 10.1083/jcb.202201088] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 07/19/2022] [Accepted: 09/30/2022] [Indexed: 11/22/2022] Open
Abstract
Virus assembly, which takes place during the late stage of viral replication, is essential for virus propagation. However, the underlying mechanisms remain poorly understood, especially for viruses with complicated structures. Here, we use correlative light and electron microscopy to examine the formation of cytoplasmic virion assembly compartments (cVACs) during infection by a γ-herpesvirus. These cVACs are membraneless organelles with liquid-like properties. Formation of cVACs during virus infection is mediated by ORF52, an abundant tegument protein. ORF52 undergoes liquid-liquid phase separation (LLPS), which is promoted by both DNA and RNA. Disrupting ORF52 phase separation blocks cVACs formation and virion production. These results demonstrate that phase separation of ORF52 is critical for cVACs formation. Our work defines herpesvirus cVACs as membraneless compartments that are generated through a process of LLPS mediated by a tegument protein and adds to the cellular processes that are facilitated by phase separation.
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Affiliation(s)
- Sheng Zhou
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Zhifei Fu
- University of Chinese Academy of Sciences, Beijing, China,Public Technology Service Center, Fujian Medical University, Fujian, China,CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,CAS Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Ziwei Zhang
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Xing Jia
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Guangjun Xu
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Long Sun
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Fei Sun
- CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Pu Gao
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Pingyong Xu
- University of Chinese Academy of Sciences, Beijing, China,CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,CAS Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Hongyu Deng
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China,CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,Correspondence to Hongyu Deng:
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13
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Schwoerer MP, Ploss A. Barriers to hepatitis C virus infection in mice. Curr Opin Virol 2022; 56:101273. [PMID: 36244239 DOI: 10.1016/j.coviro.2022.101273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/14/2022] [Indexed: 11/29/2022]
Abstract
Hepatitis C virus (HCV) is unable to infect mice, a fact that has severely limited their use as small-animal models for HCV pathogenesis and as tools for HCV vaccine development. HCV is blocked at various stages of its life cycle in mouse cells, due to incompatibility with host factors, the presence of dominant restriction factors, and effective immune responses. Molecular mechanisms for several such blocks have been characterized. The stepwise understanding of these limitations in mice will enable the development of an immunocompetent mouse that can fully support HCV infection and exhibit disease similar to that of infected humans.
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Affiliation(s)
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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14
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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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15
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Belachew B, Gao J, Byrd AK, Raney KD. Hepatitis C virus non-structural protein NS3 unfolds viral G-quadruplex RNA structures. J Biol Chem 2022; 298:102486. [PMID: 36108740 PMCID: PMC9582721 DOI: 10.1016/j.jbc.2022.102486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/17/2022] [Accepted: 09/03/2022] [Indexed: 11/29/2022] Open
Abstract
Hepatitis C virus (HCV) is a major cause of liver-related diseases and hepatocellular carcinoma. The helicase domain of one of the nonstructural proteins of HCV, NS3 (nonstructural protein 3), is essential for viral replication; however, its specific biological role is still under investigation. Here, we set out to determine the interaction between a purified recombinant full length NS3 and synthetic guanine-rich substrates that represent the conserved G-quadruplex (G4)-forming sequences in the HCV-positive and HCV-negative strands. We performed fluorescence anisotropy binding, G4 reporter duplex unwinding, and G4RNA trapping assays to determine the binding and G4 unfolding activity of NS3. Our data suggest that NS3 can unfold the conserved G4 structures present within the genome and the negative strand of HCV. Additionally, we found the activity of NS3 on a G4RNA was reduced significantly in the presence of a G4 ligand. The ability of NS3 to unfold HCV G4RNA could imply a novel biological role of the viral helicase in replication.
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Affiliation(s)
- Binyam Belachew
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Jun Gao
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Alicia K Byrd
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205.
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16
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Neufeldt CJ, Cortese M. Membrane architects: how positive-strand RNA viruses restructure the cell. J Gen Virol 2022; 103. [PMID: 35976091 DOI: 10.1099/jgv.0.001773] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Virus infection is a process that requires combined contributions from both virus and host factors. For this process to be efficient within the crowded host environment, viruses have evolved ways to manipulate and reorganize host structures to produce cellular microenvironments. Positive-strand RNA virus replication and assembly occurs in association with cytoplasmic membranes, causing a reorganization of these membranes to create microenvironments that support viral processes. Similarities between virus-induced membrane domains and cellular organelles have led to the description of these structures as virus replication organelles (vRO). Electron microscopy analysis of vROs in positive-strand RNA virus infected cells has revealed surprising morphological similarities between genetically diverse virus species. For all positive-strand RNA viruses, vROs can be categorized into two groups: those that make invaginations into the cellular membranes (In-vRO), and those that cause the production of protrusions from cellular membranes (Pr-vRO), most often in the form of double membrane vesicles (DMVs). In this review, we will discuss the current knowledge on the structure and biogenesis of these two different vRO classes as well as comparing morphology and function of vROs between various positive-strand RNA viruses. Finally, we will discuss recent studies describing pharmaceutical intervention in vRO formation as an avenue to control virus infection.
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Affiliation(s)
- Christopher John Neufeldt
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Mirko Cortese
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
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17
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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18
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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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19
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Badami E, Busà R, Douradinha B, Russelli G, Miceli V, Gallo A, Zito G, Conaldi PG, Iannolo G. Hepatocellular carcinoma, hepatitis C virus infection and miRNA involvement: Perspectives for new therapeutic approaches. World J Gastroenterol 2022; 28:2417-2428. [PMID: 35979260 PMCID: PMC9258280 DOI: 10.3748/wjg.v28.i22.2417] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/22/2022] [Accepted: 04/15/2022] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis C virus (HCV) infection is the principal etiology of cirrhosis and, ultimately, hepatocellular carcinoma (HCC). At present, approximately 71 million people are chronically infected with HCV, and 10%–20% of these are expected to develop severe liver complications throughout their lifetime. Scientific evidence has clearly shown the causal association between miRNAs, HCV infection and HCC. Although it is not completely clear whether miRNA dysregulation in HCC is the cause or the consequence of its development, variations in miRNA patterns have been described in different liver diseases, including HCC. Many studies have analyzed the importance of circulating miRNAs and their effect on cell proliferation and apoptosis. In this Review, we aim to summarize current knowledge on the association between miRNA, HCV and HCC from a diagnostic point of view, and also the potential implications for therapeutic approaches.
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Affiliation(s)
- Ester Badami
- Regenerative Medicine and Immunotherapy Area, Fondazione Ri.MED, Palermo 90127, Italy
| | - Rosalia Busà
- Department of Research, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (IRCCS-ISMETT), Palermo 90127, Italy
| | - Bruno Douradinha
- Regenerative Medicine and Immunotherapy Area, Fondazione Ri.MED, Palermo 90127, Italy
| | - Giovanna Russelli
- Department of Research, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (IRCCS-ISMETT), Palermo 90127, Italy
| | - Vitale Miceli
- Department of Research, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (IRCCS-ISMETT), Palermo 90127, Italy
| | - Alessia Gallo
- Department of Research, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (IRCCS-ISMETT), Palermo 90127, Italy
| | - Giovanni Zito
- Department of Research, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (IRCCS-ISMETT), Palermo 90127, Italy
| | - Pier Giulio Conaldi
- Department of Research, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (IRCCS-ISMETT), Palermo 90127, Italy
| | - Gioacchin Iannolo
- Department of Research, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (IRCCS-ISMETT), Palermo 90127, Italy
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20
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Han J, Kyu Lee M, Jang Y, Cho WJ, Kim M. Repurposing of cyclophilin A inhibitors as broad-spectrum antiviral agents. Drug Discov Today 2022; 27:1895-1912. [PMID: 35609743 PMCID: PMC9123807 DOI: 10.1016/j.drudis.2022.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/30/2022] [Accepted: 05/18/2022] [Indexed: 12/28/2022]
Abstract
Cyclophilin A (CypA) is linked to diverse human diseases including viral infections. With the worldwide emergence of severe acute respiratory coronavirus 2 (SARS-CoV-2), drug repurposing has been highlighted as a strategy with the potential to speed up antiviral development. Because CypA acts as a proviral component in hepatitis C virus, coronavirus and HIV, its inhibitors have been suggested as potential treatments for these infections. Here, we review the structure of cyclosporin A and sanglifehrin A analogs as well as synthetic micromolecules inhibiting CypA; and we discuss their broad-spectrum antiviral efficacy in the context of the virus lifecycle.
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Affiliation(s)
- Jinhe Han
- College of Pharmacy, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Myoung Kyu Lee
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34114, Republic of Korea
| | - Yejin Jang
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34114, Republic of Korea
| | - Won-Jea Cho
- College of Pharmacy, Chonnam National University, Gwangju, 61186, Republic of Korea.
| | - Meeheyin Kim
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34114, Republic of Korea; Graduate School of New Drug Discovery and Development, Chungnam National University, Daejeon 34134, Republic of Korea.
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21
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Miyamoto D, Takeuchi K, Chihara K, Fujieda S, Sada K. Protein tyrosine kinase Abl promotes hepatitis C virus particle assembly via interaction with viral substrate activator NS5A. J Biol Chem 2022; 298:101804. [PMID: 35257746 PMCID: PMC8980994 DOI: 10.1016/j.jbc.2022.101804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 11/30/2022] Open
Abstract
Previously, we reported that knockdown of Abl protein tyrosine kinase by shRNA or pharmacological inhibition suppresses particle assembly of J6/JFH1 strain–derived hepatitis C virus (HCV) in Huh-7.5 cells. However, the detailed mechanism by which Abl regulates HCV replication remained unclear. In this study, we established Abl-deficient (Abl−) cells through genome editing and compared HCV production between Abl− cells expressing WT or kinase-dead Abl and parental Huh-7.5 cells. Our findings revealed that Abl expression was not required from the stages of virus attachment and entry to viral gene expression; however, the kinase activity of Abl was necessary for the assembly of HCV particles. Reconstitution experiments using human embryonic kidney 293T cells revealed that phosphorylation of Tyr412 in the activation loop of Abl was enhanced by coexpression with the viral nonstructural protein 5A (NS5A) and was abrogated by the substitution of NS5A Tyr330 with Phe (Y330F), suggesting that NS5A functions as a substrate activator of Abl. Abl–NS5A association was also attenuated by the Y330F mutation of NS5A or the kinase-dead Abl, and Abl Tyr412 phosphorylation was not enhanced by NS5A bearing a mutation disabling homodimerization, although the association of Abl with NS5A was still observed. Taken together, these results demonstrate that Abl forms a phosphorylation-dependent complex with dimeric NS5A necessary for viral particle assembly, but that Abl is capable of complex formation with monomeric NS5A regardless of tyrosine phosphorylation. Our findings provide the foundation of a molecular basis for a new hepatitis C treatment strategy using Abl inhibitors.
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Affiliation(s)
- Daisuke Miyamoto
- Department of Otorhinolaryngology Head & Neck Surgery, Faculty of Medical Sciences, University of Fukui, Fukui, Japan; Department of Genome Science and Microbiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Kenji Takeuchi
- Department of Genome Science and Microbiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan; Organization for Life Science Advancement Programs, University of Fukui, Fukui, Japan
| | - Kazuyasu Chihara
- Department of Genome Science and Microbiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan; Organization for Life Science Advancement Programs, University of Fukui, Fukui, Japan
| | - Shigeharu Fujieda
- Department of Otorhinolaryngology Head & Neck Surgery, Faculty of Medical Sciences, University of Fukui, Fukui, Japan; Organization for Life Science Advancement Programs, University of Fukui, Fukui, Japan
| | - Kiyonao Sada
- Department of Genome Science and Microbiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan; Organization for Life Science Advancement Programs, University of Fukui, Fukui, Japan.
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22
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Bulankina AV, Richter RM, Welsch C. Regulatory Role of Phospholipids in Hepatitis C Virus Replication and Protein Function. Pathogens 2022; 11:102. [PMID: 35056049 PMCID: PMC8779051 DOI: 10.3390/pathogens11010102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 11/16/2022] Open
Abstract
Positive-strand RNA viruses such as hepatitis C virus (HCV) hijack key factors of lipid metabolism of infected cells and extensively modify intracellular membranes to support the viral lifecycle. While lipid metabolism plays key roles in viral particle assembly and maturation, viral RNA synthesis is closely linked to the remodeling of intracellular membranes. The formation of viral replication factories requires a number of interactions between virus proteins and host factors including lipids. The structure-function relationship of those proteins is influenced by their lipid environments and lipids that selectively modulate protein function. Here, we review our current understanding on the roles of phospholipids in HCV replication and of lipid-protein interactions in the structure-function relationship of the NS5A protein. NS5A is a key factor in membrane remodeling in HCV-infected cells and is known to recruit phosphatidylinositol 4-kinase III alpha to generate phosphatidylinositol 4-phosphate at the sites of replication. The dynamic interplay between lipids and viral proteins within intracellular membranes is likely key towards understanding basic mechanisms in the pathobiology of virus diseases, the mode of action of specific antiviral agents and related drug resistance mechanisms.
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Affiliation(s)
- Anna V. Bulankina
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany; (A.V.B.); (R.M.R.)
- Research Group “Molecular Evolution & Adaptation”, 60590 Frankfurt, Germany
| | - Rebecca M. Richter
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany; (A.V.B.); (R.M.R.)
- Research Group “Molecular Evolution & Adaptation”, 60590 Frankfurt, Germany
| | - Christoph Welsch
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany; (A.V.B.); (R.M.R.)
- Research Group “Molecular Evolution & Adaptation”, 60590 Frankfurt, Germany
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23
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Abstract
RNA viruses cause many routine illnesses, such as the common cold and the flu. Recently, more deadly diseases have emerged from this family of viruses. The hepatitis C virus has had a devastating impact worldwide. Despite the cures developed in the U.S. and Europe, economically disadvantaged countries remain afflicted by HCV infection due to the high cost of these medications. More recently, COVID-19 has swept across the world, killing millions and disrupting economies and lifestyles; the virus responsible for this pandemic is a coronavirus. Our understanding of HCV and SARS CoV-2 replication is still in its infancy. Helicases play a critical role in the replication, transcription and translation of viruses. These key enzymes need extensive study not only as an essential player in the viral lifecycle, but also as targets for antiviral therapeutics. In this review, we highlight the current knowledge for RNA helicases of high importance to human health.
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Affiliation(s)
- John C Marecki
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Binyam Belachew
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Jun Gao
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
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PIAS1 Regulates Hepatitis C Virus-Induced Lipid Droplet Accumulation by Controlling Septin 9 and Microtubule Filament Assembly. Pathogens 2021; 10:pathogens10101327. [PMID: 34684276 PMCID: PMC8537804 DOI: 10.3390/pathogens10101327] [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: 09/07/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 01/22/2023] Open
Abstract
Chronic hepatitis C virus (HCV) infection often leads to fibrosis and chronic hepatitis, then cirrhosis and ultimately hepatocellular carcinoma (HCC). The processes of the HVC life cycle involve intimate interactions between viral and host cell proteins and lipid metabolism. However, the molecules and mechanisms involved in this tripartite interaction remain poorly understood. Herein, we show that the infection of HCC-derived Huh7.5 cells with HCV promotes upregulation of the protein inhibitor of activated STAT1 (PIAS1). Reciprocally, PIAS1 regulated the expression of HCV core protein and HCV-induced LD accumulation and impaired HCV replication. Furthermore, PIAS1 controlled HCV-promoted septin 9 filament formation and microtubule polymerization. Subsequently, we found that PIAS1 interacted with septin 9 and controlled its assembly on filaments, which thus affected septin 9-induced lipid droplet accumulation. Taken together, these data reveal that PIAS1 regulates the accumulation of lipid droplets and offer a meaningful insight into how HCV interacts with host proteins.
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25
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Borgia M, Dal Bo M, Toffoli G. Role of Virus-Related Chronic Inflammation and Mechanisms of Cancer Immune-Suppression in Pathogenesis and Progression of Hepatocellular Carcinoma. Cancers (Basel) 2021; 13:cancers13174387. [PMID: 34503196 PMCID: PMC8431318 DOI: 10.3390/cancers13174387] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Hepatocellular carcinoma pathogenesis is dependent on a chronic inflammation caused by several factors, including hepatotropic viruses, such as HCV and HBV. This chronic inflammation is established in the context of the immunotolerogenic environment peculiar of the liver, in which the immune system can be stimulated by HCV and HBV viral antigens. This complex interaction can be influenced by direct-acting antiviral drug treatments, capable of (almost totally) rapidly eradicating HCV infection. The influence of anti-viral treatments on HCC pathogenesis and progression remains to be fully clarified. Abstract Hepatocellular carcinoma (HCC) can be classified as a prototypical inflammation-driven cancer that generally arises from a background of liver cirrhosis, but that in the presence of nonalcoholic steatohepatitis (NASH), could develop in the absence of fibrosis or cirrhosis. Tumor-promoting inflammation characterizes HCC pathogenesis, with an epidemiology of the chronic liver disease frequently encompassing hepatitis virus B (HBV) or C (HCV). HCC tumor onset and progression is a serial and heterogeneous process in which intrinsic factors, such as genetic mutations and chromosomal instability, are closely associated with an immunosuppressive tumor microenvironment (TME), which may have features associated with the etiopathogenesis and expression of the viral antigens, which favor the evasion of tumor neoantigens to immune surveillance. With the introduction of direct-acting antiviral (DAA) therapies for HCV infection, sustained virological response (SVR) has become very high, although occurrence of HCC and reactivation of HBV in patients with co-infection, who achieved SVR in short term, have been observed in a significant proportion of treated cases. In this review, we discuss the main molecular and TME features that are responsible for HCC pathogenesis and progression. Peculiar functional aspects that could be related to the presence and treatment of HCV/HBV viral infections are also dealt with.
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26
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Furuita K, Hiraoka M, Hanada K, Fujiwara T, Kojima C. Sequence requirements of the FFAT-like motif for specific binding to VAP-A are revealed by NMR. FEBS Lett 2021; 595:2248-2256. [PMID: 34312846 DOI: 10.1002/1873-3468.14166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/06/2021] [Accepted: 07/19/2021] [Indexed: 01/21/2023]
Abstract
The endoplasmic reticulum transmembrane protein vesicle-associated membrane protein-associated protein (VAP) plays a central role in the formation and function of membrane contact sites (MCS) through its interactions with proteins. The major sperm protein (MSP) domain of VAP binds to a variety of sequences which are referred to as FFAT-like motifs. In this study, we investigated the interactions of eight peptides containing FFAT-like motifs with the VAP-A MSP domain (VAP-AMSP ) by solution NMR. Six of eight peptides are specifically bound to VAP-A. Furthermore, we found that the RNA-dependent RNA polymerase of severe acute respiratory syndrome coronavirus 2 has an FFAT-like motif which specifically binds to VAP-AMSP as well as other FFAT-like motifs. Our results will contribute to the discovery of new VAP interactors.
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Affiliation(s)
- Kyoko Furuita
- Institute for Protein Research, Osaka University, Suita, Japan
| | - Marina Hiraoka
- Graduate School of Engineering Science, Yokohama National University, Yokohama, Japan
| | - Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Chojiro Kojima
- Institute for Protein Research, Osaka University, Suita, Japan.,Graduate School of Engineering Science, Yokohama National University, Yokohama, Japan
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27
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Yu T, Yang Q, Tian F, Chang H, Hu Z, Yu B, Han L, Xing Y, Jiu Y, He Y, Zhong J. Glycometabolism regulates hepatitis C virus release. PLoS Pathog 2021; 17:e1009746. [PMID: 34297778 PMCID: PMC8301660 DOI: 10.1371/journal.ppat.1009746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/23/2021] [Indexed: 01/01/2023] Open
Abstract
HCV cell-culture system uses hepatoma-derived cell lines for efficient virus propagation. Tumor cells cultured in glucose undergo active aerobic glycolysis, but switch to oxidative phosphorylation for energy production when cultured in galactose. Here, we investigated whether modulation of glycolysis in hepatocytes affects HCV infection. We showed HCV release, but not entry, genome replication or virion assembly, is significantly blocked when cells are cultured in galactose, leading to accumulation of intracellular infectious virions within multivesicular body (MVB). Blockade of the MVB-lysosome fusion or treatment with pro-inflammatory cytokines promotes HCV release in galactose. Furthermore, we found this glycometabolic regulation of HCV release is mediated by MAPK-p38 phosphorylation. Finally, we showed HCV cell-to-cell transmission is not affected by glycometabolism, suggesting that HCV cell-to-supernatant release and cell-to-cell transmission are two mechanistically distinct pathways. In summary, we demonstrated glycometabolism regulates the efficiency and route of HCV release. We proposed HCV may exploit the metabolic state in hepatocytes to favor its spread through the cell-to-cell transmission in vivo to evade immune response. Hepatitis C virus (HCV) is a positive-stranded RNA virus that causes acute and chronic hepatitis and hepatocellular carcinoma. HCV infectious cycle comprises viral entry, uncoating, translation and replication of viral RNA, assembly into new virions and release. Establishment of HCV cell culture system (HCVcc) has yielded many insights into complete HCV infectious cycle in Huh7 cell and Huh7-derived human hepatoma cell lines. However, because hepatoma-derived cell lines and hepatocytes vary in metabolism, HCV infectious cycle in tumor cell lines and the patient’s liver may also be different. Therefore, we explored the alterations of HCV infectious cycle by forcing the tumor cell lines to switch their glycometabolic pathways. We found that HCV release can be blocked by culturing cells in galactose-containing medium, leading to accumulation of intracellular infectious virions within MVB. Moreover, we provided new evidence to suggest that HCV cell-to-cell transmission may be mechanistically distinct from cell-to-supernatant release. Finally, we proposed a new concept that HCV release from hepatocytes into circulation may be naturally inefficient due to the metabolic state in liver that may favor more HCV cell-to-cell transmission. This strategy would allow HCV to effectively evade neutralizing antibodies to establish persistent infection.
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Affiliation(s)
- Tao Yu
- Unit of Viral Hepatitis, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiankun Yang
- Unit of Viral Hepatitis, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fangling Tian
- Unit of Viral Hepatitis, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- ShanghaiTech University, Shanghai, China
| | - Haishuang Chang
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai
| | - Zhenzheng Hu
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai
| | - Bowen Yu
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai
| | - Lin Han
- Unit of Viral Hepatitis, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- ShanghaiTech University, Shanghai, China
| | - Yifan Xing
- Unit of Viral Hepatitis, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- Cell Biology and Imaging Study of Pathogen Host Interaction Unit, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
| | - Yaming Jiu
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai
- Cell Biology and Imaging Study of Pathogen Host Interaction Unit, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
| | - Yongning He
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai
| | - Jin Zhong
- Unit of Viral Hepatitis, Institut Pasteur of Shanghai, CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- ShanghaiTech University, Shanghai, China
- * E-mail:
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28
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Lashkevich KA, Dmitriev SE. mRNA Targeting, Transport and Local Translation in Eukaryotic Cells: From the Classical View to a Diversity of New Concepts. Mol Biol 2021; 55:507-537. [PMID: 34092811 PMCID: PMC8164833 DOI: 10.1134/s0026893321030080] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 02/26/2021] [Accepted: 03/12/2021] [Indexed: 12/28/2022]
Abstract
Spatial organization of protein biosynthesis in the eukaryotic cell has been studied for more than fifty years, thus many facts have already been included in textbooks. According to the classical view, mRNA transcripts encoding secreted and transmembrane proteins are translated by ribosomes associated with endoplasmic reticulum membranes, while soluble cytoplasmic proteins are synthesized on free polysomes. However, in the last few years, new data has emerged, revealing selective translation of mRNA on mitochondria and plastids, in proximity to peroxisomes and endosomes, in various granules and at the cytoskeleton (actin network, vimentin intermediate filaments, microtubules and centrosomes). There are also long-standing debates about the possibility of protein synthesis in the nucleus. Localized translation can be determined by targeting signals in the synthesized protein, nucleotide sequences in the mRNA itself, or both. With RNA-binding proteins, many transcripts can be assembled into specific RNA condensates and form RNP particles, which may be transported by molecular motors to the sites of active translation, form granules and provoke liquid-liquid phase separation in the cytoplasm, both under normal conditions and during cell stress. The translation of some mRNAs occurs in specialized "translation factories," assemblysomes, transperons and other structures necessary for the correct folding of proteins, interaction with functional partners and formation of oligomeric complexes. Intracellular localization of mRNA has a significant impact on the efficiency of its translation and presumably determines its response to cellular stress. Compartmentalization of mRNAs and the translation machinery also plays an important role in viral infections. Many viruses provoke the formation of specific intracellular structures, virus factories, for the production of their proteins. Here we review the current concepts of the molecular mechanisms of transport, selective localization and local translation of cellular and viral mRNAs, their effects on protein targeting and topogenesis, and on the regulation of protein biosynthesis in different compartments of the eukaryotic cell. Special attention is paid to new systems biology approaches, providing new cues to the study of localized translation.
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Affiliation(s)
- Kseniya A Lashkevich
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119234 Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, Moscow State University, 119234 Moscow, Russia
| | - Sergey E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119234 Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, Moscow State University, 119234 Moscow, Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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Reungoat E, Grigorov B, Zoulim F, Pécheur EI. Molecular Crosstalk between the Hepatitis C Virus and the Extracellular Matrix in Liver Fibrogenesis and Early Carcinogenesis. Cancers (Basel) 2021; 13:cancers13092270. [PMID: 34065048 PMCID: PMC8125929 DOI: 10.3390/cancers13092270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/01/2021] [Accepted: 05/03/2021] [Indexed: 12/16/2022] Open
Abstract
Simple Summary In the era of direct-acting antivirals against the hepatitis C virus (HCV), curing chronic hepatitis C has become a reality. However, while replicating chronically, HCV creates a peculiar state of inflammation and oxidative stress in the infected liver, which fuels DNA damage at the onset of HCV-induced hepatocellular carcinoma (HCC). This cancer, the second leading cause of death by cancer, remains of bad prognosis when diagnosed. This review aims to decipher how HCV durably alters elements of the extracellular matrix that compose the liver microenvironment, directly through its viral proteins or indirectly through the induction of cytokine secretion, thereby leading to liver fibrosis, cirrhosis, and, ultimately, HCC. Abstract Chronic infection by the hepatitis C virus (HCV) is a major cause of liver diseases, predisposing to fibrosis and hepatocellular carcinoma. Liver fibrosis is characterized by an overly abundant accumulation of components of the hepatic extracellular matrix, such as collagen and elastin, with consequences on the properties of this microenvironment and cancer initiation and growth. This review will provide an update on mechanistic concepts of HCV-related liver fibrosis/cirrhosis and early stages of carcinogenesis, with a dissection of the molecular details of the crosstalk during disease progression between hepatocytes, the extracellular matrix, and hepatic stellate cells.
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30
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Abstract
C6 deamination of adenosine (A) to inosine (I) in double-stranded RNA (dsRNA) is catalyzed by a family of enzymes known as ADARs (adenosine deaminases acting on RNA) encoded by three genes in mammals. Alternative promoters and splicing produce two ADAR1 proteins, an interferon-inducible cytoplasmic p150 and a constitutively expressed p110 that like ADAR2 is a nuclear enzyme. ADAR3 lacks deaminase activity. A-to-I editing occurs with both viral and cellular RNAs. Deamination activity is dependent on dsRNA substrate structure and regulatory RNA-binding proteins and ranges from highly site selective with hepatitis D RNA and glutamate receptor precursor messenger RNA (pre-mRNA) to hyperediting of measles virus and polyomavirus transcripts and cellular inverted Alu elements. Because I base-pairs as guanosine instead of A, editing can alter mRNA decoding, pre-mRNA splicing, and microRNA silencing. Editing also alters dsRNA structure, thereby suppressing innate immune responses including interferon production and action. Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Christian K Pfaller
- Division of Veterinary Medicine, Paul-Ehrlich-Institute, Langen 63225, Germany
| | - Cyril X George
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106, USA;
| | - Charles E Samuel
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106, USA;
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31
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Tarannum H, Chauhan B, Samadder A, Roy H, Nandi S. To Explore the Potential Targets and Current Structure-based Design Strategies Utilizing Co-crystallized Ligand to Combat HCV. Curr Drug Targets 2021; 22:590-604. [PMID: 32720601 DOI: 10.2174/1389450121999200727215020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/05/2020] [Accepted: 05/11/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Hepatitis C Virus (HCV) belongs to the Hepacivirus family. HCV has been designated as a very dreadful virus as it can attack the liver, causing inflammation and even may lead to cancer in chronic conditions. It was estimated that 71 million people around the world have chronic HCV infection. World Health Organization (WHO) reported that about 399000 people died because of chronic cirrhosis and liver cancer globally. In spite of the abundance of availability of drugs for the treatment of HCV, however, the issue of drug resistance surpasses all the possibilities of therapeutic management of HCV. Therefore, to address this issue of 'drug-resistance', various HCV targets were explored to quest the evaluation of the mechanism of the disease progression. METHODS An attempt has been made in the present study to explore the various targets of HCV involved in the mechanism(s) of the disease initiation and progression and to focus on the mode of binding of ligands, which are co-crystallized at the active cavity of different HCV targets. CONCLUSION The present study could predict some crucial features of these ligands, which possibly interacted with various amino acid residues responsible for their biological activity and molecular signaling pathway(s). Such binding mode may be considered as a template for the high throughput screening and designing of active congeneric ligands to combat HCV.
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Affiliation(s)
- Heena Tarannum
- Department of Pharmaceutical Chemistry, Global Institute of Pharmaceutical Education and Research (Affiliated to Uttarakhand Technical University), Kashipur-244713, India
| | - Bhumika Chauhan
- Department of Pharmaceutical Chemistry, Global Institute of Pharmaceutical Education and Research (Affiliated to Uttarakhand Technical University), Kashipur-244713, India
| | - Asmita Samadder
- Cytogenetics and Molecular Biology Lab., Department of Zoology, University of Kalyani, Kalyani, Nadia, 741235, India
| | - Harekrishna Roy
- Nirmala College of Pharmacy, Mangalagiri, Guntur, Andhra Pradesh, 522503, India
| | - Sisir Nandi
- Department of Pharmaceutical Chemistry, Global Institute of Pharmaceutical Education and Research (Affiliated to Uttarakhand Technical University), Kashipur-244713, India
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Abstract
Antibody responses in hepatitis C virus (HCV) have been a rather mysterious research topic for many investigators working in the field. Chronic HCV infection is often associated with dysregulation of immune functions particularly in B cells, leading to abnormal lymphoproliferation or the production of autoantibodies that exacerbate inflammation and extrahepatic diseases. When considering the antiviral function of antibody, it was difficult to endorse its role in HCV protection, whereas T-cell response has been shown unequivocally critical for natural recovery. Recent breakthroughs in the study of HCV and antigen-specific antibody responses provide important insights into viral vulnerability to antibodies and the immunogenetic and structural properties of the neutralizing antibodies. The new knowledge reinvigorates HCV vaccine research by illuminating a new path for the rational design of vaccine antigens to elicit broadly neutralizing antibodies for protection.
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Affiliation(s)
- Mansun Law
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California 92109, USA
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33
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Kim GW, Siddiqui A. The role of N6-methyladenosine modification in the life cycle and disease pathogenesis of hepatitis B and C viruses. Exp Mol Med 2021; 53:339-345. [PMID: 33742132 PMCID: PMC8080661 DOI: 10.1038/s12276-021-00581-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/11/2022] Open
Abstract
N6-methyladenosine (m6A) is the most prevalent modification of mammalian cellular RNAs. m6A methylation is linked to epigenetic regulation of several aspects of gene expression, including RNA stability, splicing, nuclear export, RNA folding, and translational activity. m6A modification is reversibly catalyzed by methyltransferases (m6A writers) and demethylases (m6A erasers), and the dynamics of m6A-modified RNA are regulated by m6A-binding proteins (m6A readers). Recently, several studies have shown that m6A methylation sites have been identified in hepatitis B virus (HBV) transcripts and the hepatitis C virus (HCV) RNA genome. Here, we review the role of m6A modification in HBV/HCV replication and its contribution to liver disease pathogenesis. A better understanding of the functions of m6A methylation in the life cycles of HBV and HCV is required to establish the role of these modifications in liver diseases associated with these viral infections.
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Affiliation(s)
- Geon-Woo Kim
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Aleem Siddiqui
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
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Vairetti M, Di Pasqua LG, Cagna M, Richelmi P, Ferrigno A, Berardo C. Changes in Glutathione Content in Liver Diseases: An Update. Antioxidants (Basel) 2021; 10:364. [PMID: 33670839 PMCID: PMC7997318 DOI: 10.3390/antiox10030364] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 02/07/2023] Open
Abstract
Glutathione (GSH), a tripeptide particularly concentrated in the liver, is the most important thiol reducing agent involved in the modulation of redox processes. It has also been demonstrated that GSH cannot be considered only as a mere free radical scavenger but that it takes part in the network governing the choice between survival, necrosis and apoptosis as well as in altering the function of signal transduction and transcription factor molecules. The purpose of the present review is to provide an overview on the molecular biology of the GSH system; therefore, GSH synthesis, metabolism and regulation will be reviewed. The multiple GSH functions will be described, as well as the importance of GSH compartmentalization into distinct subcellular pools and inter-organ transfer. Furthermore, we will highlight the close relationship existing between GSH content and the pathogenesis of liver disease, such as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), chronic cholestatic injury, ischemia/reperfusion damage, hepatitis C virus (HCV), hepatitis B virus (HBV) and hepatocellular carcinoma. Finally, the potential therapeutic benefits of GSH and GSH-related medications, will be described for each liver disorder taken into account.
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Affiliation(s)
| | - Laura Giuseppina Di Pasqua
- Unit of Cellular and Molecular Pharmacology and Toxicology, Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy; (M.V.); (M.C.); (P.R.); (C.B.)
| | | | | | - Andrea Ferrigno
- Unit of Cellular and Molecular Pharmacology and Toxicology, Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy; (M.V.); (M.C.); (P.R.); (C.B.)
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35
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Ma Y, Frutos-Beltrán E, Kang D, Pannecouque C, De Clercq E, Menéndez-Arias L, Liu X, Zhan P. Medicinal chemistry strategies for discovering antivirals effective against drug-resistant viruses. Chem Soc Rev 2021; 50:4514-4540. [PMID: 33595031 DOI: 10.1039/d0cs01084g] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
During the last forty years we have witnessed impressive advances in the field of antiviral drug discovery culminating with the introduction of therapies able to stop human immunodeficiency virus (HIV) replication, or cure hepatitis C virus infections in people suffering from liver disease. However, there are important viral diseases without effective treatments, and the emergence of drug resistance threatens the efficacy of successful therapies used today. In this review, we discuss strategies to discover antiviral compounds specifically designed to combat drug resistance. Currently, efforts in this field are focused on targeted proteins (e.g. multi-target drug design strategies), but also on drug conformation (either improving drug positioning in the binding pocket or introducing conformational constraints), in the introduction or exploitation of new binding sites, or in strengthening interaction forces through the introduction of multiple hydrogen bonds, covalent binding, halogen bonds, additional van der Waals forces or multivalent binding. Among the new developments, proteolysis targeting chimeras (PROTACs) have emerged as a valid approach taking advantage of intracellular mechanisms involving protein degradation by the ubiquitin-proteasome system. Finally, several molecules targeting host factors (e.g. human dihydroorotate dehydrogenase and DEAD-box polypeptide 3) have been identified as broad-spectrum antiviral compounds. Implementation of herein described medicinal chemistry strategies are expected to contribute to the discovery of new drugs effective against current and future threats due to emerging and re-emerging viral pandemics.
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Affiliation(s)
- Yue Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, Ji'nan, 250012, Shandong Province, P. R. China.
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36
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Chu JYK, Ou JHJ. Autophagy in HCV Replication and Protein Trafficking. Int J Mol Sci 2021; 22:ijms22031089. [PMID: 33499186 PMCID: PMC7865906 DOI: 10.3390/ijms22031089] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 12/11/2022] Open
Abstract
Autophagy is a catabolic process that is important for maintaining cellular homeostasis. It is also known to possess other functions including protein trafficking and anti-microbial activities. Hepatitis C virus (HCV) is known to co-opt cellular autophagy pathway to promote its own replication. HCV regulates autophagy through multiple mechanisms to control intracellular protein and membrane trafficking to enhance its replication and suppress host innate immune response. In this review, we discuss the current knowledge on the interplay between HCV and autophagy and the crosstalk between HCV-induced autophagy and host innate immune responses.
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Zhang J, Lan Y, Sanyal S. Membrane heist: Coronavirus host membrane remodeling during replication. Biochimie 2020; 179:229-236. [PMID: 33115667 PMCID: PMC7585727 DOI: 10.1016/j.biochi.2020.10.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/28/2020] [Accepted: 10/22/2020] [Indexed: 02/06/2023]
Abstract
The ongoing pandemic of COVID-19 (Coronavirus Disease-2019), a respiratory disease caused by the novel coronavirus strain, SARS-CoV-2, has affected more than 42 million people already, with more than one million deaths worldwide (as of October 25, 2020). We are in urgent need of therapeutic interventions that target the host-virus interface, which requires a molecular understanding of the SARS-CoV-2 life-cycle. Like other positive-sense RNA viruses, coronaviruses remodel intracellular membranes to form specialized viral replication compartments, including double-membrane vesicles (DMVs), where viral RNA genome replication takes place. Here we review the current knowledge of the structure, lipid composition, function, and biogenesis of coronavirus-induced DMVs, highlighting the druggable viral and cellular factors that are involved in the formation and function of DMVs.
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Affiliation(s)
- Jingshu Zhang
- Artemis One Health Research Foundation, Delft, the Netherlands
| | - Yun Lan
- HKU-Pasteur Research Pole, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Sumana Sanyal
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK; HKU-Pasteur Research Pole, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
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38
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Abstract
Liver cancer is a global problem and hepatocellular carcinoma (HCC) accounts for about 85% of this cancer. In the USA, etiologies and risk factors for HCC include chronic hepatitis C virus (HCV) infection, diabetes, non-alcoholic steatohepatitis (NASH), obesity, excessive alcohol drinking, exposure to tobacco smoke, and genetic factors. Chronic HCV infection appears to be associated with about 30% of HCC. Chronic HCV infection induces multistep changes in liver, involving metabolic disorders, steatosis, cirrhosis and HCC. Liver carcinogenesis requires initiation of neoplastic clones, and progression to clinically diagnose malignancy. Tumor progression associates with profound exhaustion of tumor-antigen-specific CD8+T cells, and accumulation of PD-1hi CD8+T cells and Tregs. In this chapter, we provide a brief description of HCV and environmental/genetic factors, immune regulation, and highlight mechanisms of HCV associated HCC. We also underscore HCV treatment and recent paradigm of HCC progression, highlighted the current treatment and potential future therapeutic opportunities.
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Sphingomyelin Is Essential for the Structure and Function of the Double-Membrane Vesicles in Hepatitis C Virus RNA Replication Factories. J Virol 2020; 94:JVI.01080-20. [PMID: 32938759 DOI: 10.1128/jvi.01080-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/05/2020] [Indexed: 02/07/2023] Open
Abstract
Some plus-stranded RNA viruses generate double-membrane vesicles (DMVs), one type of the membrane replication factories, as replication sites. Little is known about the lipid components involved in the biogenesis of these vesicles. Sphingomyelin (SM) is required for hepatitis C virus (HCV) replication, but the mechanism of SM involvement remains poorly understood. SM biosynthesis starts in the endoplasmic reticulum (ER) and gives rise to ceramide, which is transported from the ER to the Golgi by the action of ceramide transfer protein (CERT), where it can be converted to SM. In this study, inhibition of SM biosynthesis, either by using small-molecule inhibitors or by knockout (KO) of CERT, suppressed HCV replication in a genotype-independent manner. This reduction in HCV replication was rescued by exogenous SM or ectopic expression of the CERT protein, but not by ectopic expression of nonfunctional CERT mutants. Observing low numbers of DMVs in stable replicon cells treated with a SM biosynthesis inhibitor or in CERT-KO cells transfected with either HCV replicon or with constructs that drive HCV protein production in a replication-independent system indicated the significant importance of SM to DMVs. The degradation of SM of the in vitro-isolated DMVs affected their morphology and increased the vulnerability of HCV RNA and proteins to RNase and protease treatment, respectively. Poliovirus, known to induce DMVs, showed decreased replication in CERT-KO cells, while dengue virus, known to induce invaginated vesicles, did not. In conclusion, these findings indicated that SM is an essential constituent of DMVs generated by some plus-stranded RNA viruses.IMPORTANCE Previous reports assumed that sphingomyelin (SM) is essential for HCV replication, but the mechanism was unclear. In this study, we showed for the first time that SM and ceramide transfer protein (CERT), which is in the SM biosynthesis pathway, are essential for the biosynthesis of double-membrane vesicles (DMVs), the sites of viral replication. Low numbers of DMVs were observed in CERT-KO cells transfected with replicon RNA or with constructs that drive HCV protein production in a replication-independent system. HCV replication was rescued by ectopic expression of the CERT protein, but not by CERT mutants, that abolishes the binding of CERT to vesicle-associated membrane protein-associated protein (VAP) or phosphatidylinositol 4-phosphate (PI4P), indicating new roles for VAP and PI4P in HCV replication. The biosynthesis of DMVs has great importance to replication by a variety of plus-stranded RNA viruses. Understanding of this process is expected to facilitate the development of diagnosis and antivirus.
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Zitzmann C, Kaderali L, Perelson AS. Mathematical modeling of hepatitis C RNA replication, exosome secretion and virus release. PLoS Comput Biol 2020; 16:e1008421. [PMID: 33151933 PMCID: PMC7671504 DOI: 10.1371/journal.pcbi.1008421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/17/2020] [Accepted: 10/06/2020] [Indexed: 01/04/2023] Open
Abstract
Hepatitis C virus (HCV) causes acute hepatitis C and can lead to life-threatening complications if it becomes chronic. The HCV genome is a single plus strand of RNA. Its intracellular replication is a spatiotemporally coordinated process of RNA translation upon cell infection, RNA synthesis within a replication compartment, and virus particle production. While HCV is mainly transmitted via mature infectious virus particles, it has also been suggested that HCV-infected cells can secrete HCV RNA carrying exosomes that can infect cells in a receptor independent manner. In order to gain insight into these two routes of transmission, we developed a series of intracellular HCV replication models that include HCV RNA secretion and/or virus assembly and release. Fitting our models to in vitro data, in which cells were infected with HCV, suggests that initially most secreted HCV RNA derives from intracellular cytosolic plus-strand RNA, but subsequently secreted HCV RNA derives equally from the cytoplasm and the replication compartments. Furthermore, our model fits to the data suggest that the rate of virus assembly and release is limited by host cell resources. Including the effects of direct acting antivirals in our models, we found that in spite of decreasing intracellular HCV RNA and extracellular virus concentration, low level HCV RNA secretion may continue as long as intracellular RNA is available. This may possibly explain the presence of detectable levels of plasma HCV RNA at the end of treatment even in patients that ultimately attain a sustained virologic response. Approximately 70 million people are chronically infected with hepatitis C virus (HCV), which if left untreated may lead to cirrhosis and liver cancer. However, modern drug therapy is highly effective and hepatitis C is the first chronic virus infection that can be cured with short-term therapy in almost all infected individuals. The within-host transmission of HCV occurs mainly via infectious virus particles, but experimental studies suggest that there may be additional receptor-independent cell-to-cell transmission by exosomes that carry the HCV genome. In order to understand the intracellular HCV lifecycle and HCV RNA spread, we developed a series of mathematical models that take both exosomal secretion and viral secretion into account. By fitting these models to in vitro data, we found that secretion of both HCV RNA as well as virus probably occurs and that the rate of virus assembly is likely limited by cellular co-factors on which the virus strongly depends for its own replication. Furthermore, our modeling predicted that the parameters governing the processes in the viral lifecycle that are targeted by direct acting antivirals are the most sensitive to perturbations, which may help explain their ability to cure this infection.
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Affiliation(s)
- Carolin Zitzmann
- University Medicine Greifswald, Institute of Bioinformatics and Center for Functional Genomics of Microbes, Greifswald, Germany
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Lars Kaderali
- University Medicine Greifswald, Institute of Bioinformatics and Center for Functional Genomics of Microbes, Greifswald, Germany
| | - Alan S. Perelson
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- * E-mail:
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Cloherty AP, Olmstead AD, Ribeiro CM, Jean F. Hijacking of Lipid Droplets by Hepatitis C, Dengue and Zika Viruses-From Viral Protein Moonlighting to Extracellular Release. Int J Mol Sci 2020; 21:E7901. [PMID: 33114346 PMCID: PMC7662613 DOI: 10.3390/ijms21217901] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 02/06/2023] Open
Abstract
Hijacking and manipulation of host cell biosynthetic pathways by human enveloped viruses are essential for the viral lifecycle. Flaviviridae members, including hepatitis C, dengue and Zika viruses, extensively manipulate host lipid metabolism, underlining the importance of lipid droplets (LDs) in viral infection. LDs are dynamic cytoplasmic organelles that can act as sequestration platforms for a unique subset of host and viral proteins. Transient recruitment and mobilization of proteins to LDs during viral infection impacts host-cell biological properties, LD functionality and canonical protein functions. Notably, recent studies identified LDs in the nucleus and also identified that LDs are transported extracellularly via an autophagy-mediated mechanism, indicating a novel role for autophagy in Flaviviridae infections. These developments underline an unsuspected diversity and localization of LDs and potential moonlighting functions of LD-associated proteins during infection. This review summarizes recent breakthroughs concerning the LD hijacking activities of hepatitis C, dengue and Zika viruses and potential roles of cytoplasmic, nuclear and extracellular LD-associated viral proteins during infection.
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Affiliation(s)
- Alexandra P.M. Cloherty
- Amsterdam UMC, Amsterdam Institute for Infection & Immunity, Department of Experimental Immunology, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (A.P.M.C.); (C.M.S.R.)
| | - Andrea D. Olmstead
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, 3559–2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Carla M.S. Ribeiro
- Amsterdam UMC, Amsterdam Institute for Infection & Immunity, Department of Experimental Immunology, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (A.P.M.C.); (C.M.S.R.)
| | - François Jean
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, 3559–2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
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Kardani K, Basimi P, Fekri M, Bolhassani A. Antiviral therapy for the sexually transmitted viruses: recent updates on vaccine development. Expert Rev Clin Pharmacol 2020; 13:1001-1046. [PMID: 32838584 DOI: 10.1080/17512433.2020.1814743] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The sexually transmitted infections (STIs) caused by viruses including human T cell leukemia virus type-1 (HTLV-1), human immunodeficiency virus-1 (HIV-1), human simplex virus-2 (HSV-2), hepatitis C virus (HCV), hepatitis B virus (HBV), and human papillomavirus (HPV) are major public health issues. These infections can cause cancer or result in long-term health problems. Due to high prevalence of STIs, a safe and effective vaccine is required to overcome these fatal viruses. AREAS COVERED This review includes a comprehensive overview of the literatures relevant to vaccine development against the sexually transmitted viruses (STVs) using PubMed and Sciencedirect electronic search engines. Herein, we discuss the efforts directed toward development of effective vaccines using different laboratory animal models including mice, guinea pig or non-human primates in preclinical trials, and human in clinical trials with different phases. EXPERT OPINION There is no effective FDA approved vaccine against the sexually transmitted viruses (STVs) except for HBV and HPV as prophylactic vaccines. Many attempts are underway to develop vaccines against these viruses. There are several approaches for improving prophylactic or therapeutic vaccines such as heterologous prime/boost immunization, delivery system, administration route, adjuvants, etc. In this line, further studies can be helpful for understanding the immunobiology of STVs in human. Moreover, development of more relevant animal models is a worthy goal to induce effective immune responses in humans.
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Affiliation(s)
- Kimia Kardani
- Department of Hepatitis and AIDS, Pasteur Institute of Iran , Tehran, Iran
| | - Parya Basimi
- Department of Hepatitis and AIDS, Pasteur Institute of Iran , Tehran, Iran
| | - Mehrshad Fekri
- Department of Hepatitis and AIDS, Pasteur Institute of Iran , Tehran, Iran
| | - Azam Bolhassani
- Department of Hepatitis and AIDS, Pasteur Institute of Iran , Tehran, Iran
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43
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Alzahrani N, Wu MJ, Shanmugam S, Yi M. Delayed by Design: Role of Suboptimal Signal Peptidase Processing of Viral Structural Protein Precursors in Flaviviridae Virus Assembly. Viruses 2020; 12:v12101090. [PMID: 32993149 PMCID: PMC7601889 DOI: 10.3390/v12101090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/04/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
The Flaviviridae virus family is classified into four different genera, including flavivirus, hepacivirus, pegivirus, and pestivirus, which cause significant morbidity and mortality in humans and other mammals, including ruminants and pigs. These are enveloped, single-stranded RNA viruses sharing a similar genome organization and replication scheme with certain unique features that differentiate them. All viruses in this family express a single polyprotein that encodes structural and nonstructural proteins at the N- and C-terminal regions, respectively. In general, the host signal peptidase cleaves the structural protein junction sites, while virus-encoded proteases process the nonstructural polyprotein region. It is known that signal peptidase processing is a rapid, co-translational event. Interestingly, certain signal peptidase processing site(s) in different Flaviviridae viral structural protein precursors display suboptimal cleavage kinetics. This review focuses on the recent progress regarding the Flaviviridae virus genus-specific mechanisms to downregulate signal peptidase-mediated processing at particular viral polyprotein junction sites and the role of delayed processing at these sites in infectious virus particle assembly.
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44
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Ribosome Pausing at Inefficient Codons at the End of the Replicase Coding Region Is Important for Hepatitis C Virus Genome Replication. Int J Mol Sci 2020; 21:ijms21186955. [PMID: 32971876 PMCID: PMC7555993 DOI: 10.3390/ijms21186955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/26/2020] [Accepted: 09/15/2020] [Indexed: 12/17/2022] Open
Abstract
Hepatitis C virus (HCV) infects liver cells and often causes chronic infection, also leading to liver cirrhosis and cancer. In the cytoplasm, the viral structural and non-structural (NS) proteins are directly translated from the plus strand HCV RNA genome. The viral proteins NS3 to NS5B proteins constitute the replication complex that is required for RNA genome replication via a minus strand antigenome. The most C-terminal protein in the genome is the NS5B replicase, which needs to initiate antigenome RNA synthesis at the very 3′-end of the plus strand. Using ribosome profiling of cells replicating full-length infectious HCV genomes, we uncovered that ribosomes accumulate at the HCV stop codon and about 30 nucleotides upstream of it. This pausing is due to the presence of conserved rare, inefficient Wobble codons upstream of the termination site. Synonymous substitution of these inefficient codons to efficient codons has negative consequences for viral RNA replication but not for viral protein synthesis. This pausing may allow the enzymatically active replicase core to find its genuine RNA template in cis, while the protein is still held in place by being stuck with its C-terminus in the exit tunnel of the paused ribosome.
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45
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Li Z, Guo D, Qin Y, Chen M. PI4KB on Inclusion Bodies Formed by ER Membrane Remodeling Facilitates Replication of Human Parainfluenza Virus Type 3. Cell Rep 2020; 29:2229-2242.e4. [PMID: 31747597 PMCID: PMC7104050 DOI: 10.1016/j.celrep.2019.10.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/21/2019] [Accepted: 10/09/2019] [Indexed: 01/09/2023] Open
Abstract
Many positive-strand RNA viruses remodel the endomembrane to form specialized replication organelles. However, knowledge regarding whether negative-strand RNA viruses take advantage of intracellular membranes for replication is limited. Here we show that a negative-strand RNA virus, human parainfluenza virus type 3 (HPIV3), remodels the endoplasmic reticulum (ER) membrane to form inclusion bodies (IBs), whereby the phosphoprotein (P) of HPIV3 recruits phosphatidylinositol 4-kinase beta (PI4KB) to IBs to generate PI4P, creating a PI4P-enriched microenvironment to promote HPIV3 replication. In addition, we find that human respiratory syncytial virus (HRSV) also takes advantage of the ER to form IBs and that these IBs are also enriched with PI4P. The nucleoprotein of HRSV recruits PI4KB to IBs. These results suggest that paramyxoviruses also exploit the host endomembrane to form IBs and that PI4KB is recruited by viral proteins to enrich IBs with PI4P to facilitate viral replication. Inclusion bodies (IBs) of HPIV3 induce membrane rearrangement of ER PI4P generated by PI4KB on IBs facilitates replication of HPIV3 PI4KB is recruited to IBs via interaction with the HPIV3 phosphoprotein, P Remodeling ER is a general mechanism for IBs of negative-strand RNA viruses
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Affiliation(s)
- Zhifei Li
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan 430072, China
| | - Dong Guo
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan 430072, China
| | - Yali Qin
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan 430072, China.
| | - Mingzhou Chen
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan 430072, China.
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46
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Ci Y, Liu ZY, Zhang NN, Niu Y, Yang Y, Xu C, Yang W, Qin CF, Shi L. Zika NS1-induced ER remodeling is essential for viral replication. J Cell Biol 2020; 219:133534. [PMID: 31868887 PMCID: PMC7041685 DOI: 10.1083/jcb.201903062] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/29/2019] [Accepted: 11/08/2019] [Indexed: 11/22/2022] Open
Abstract
Zika virus induces the formation of vesicles from ER membrane that form viral replication factories in the ER lumen. Ci et al. show that the Zika NS1 protein plays a key role in this remodeling of the ER as the insertion of the hydrophobic regions of NS1 into the inner leaflet of the ER membrane creates the compartments essential for viral replication. Zika virus (ZIKV), a recently emerged member of the flavivirus family, forms replication compartments at the ER during its lifecycle. The proteins that are responsible for the biogenesis of replication compartments are not well defined. Here, we show that Zika nonstructural protein 1 (NS1)–induced ER remodeling is essential for viral replication. NS1 expressed in the ER lumen induced ER perinuclear aggregation with an ultrastructure resembling that of the replication compartment. Data from model membrane system indicated that the membrane-binding and membrane-remodeling properties of NS1 depend on its hydrophobic insertion into the membrane. These findings demonstrate that NS1 plays a crucial role in flavivirus replication compartment formation by remodeling the ER structure.
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Affiliation(s)
- Yali Ci
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China.,Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Zhong-Yu Liu
- Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Na-Na Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yuqiang Niu
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, China
| | - Yang Yang
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China.,Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Caimin Xu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China.,Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Wei Yang
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, China
| | - Cheng-Feng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,The First Hospital of Jilin University, Changchun, China
| | - Lei Shi
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China.,Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China
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47
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Sternberg A, McKee DL, Naujokat C. Novel Drugs Targeting the SARS-CoV-2/COVID-19 Machinery. Curr Top Med Chem 2020; 20:1423-1433. [PMID: 32416679 DOI: 10.2174/1568026620999200517043137] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 05/15/2020] [Accepted: 05/16/2020] [Indexed: 12/13/2022]
Abstract
Like other human pathogenic viruses, coronavirus SARS-CoV-2 employs sophisticated macromolecular machines for viral host cell entry, genome replication and protein processing. Such machinery encompasses SARS-CoV-2 envelope spike (S) glycoprotein required for host cell entry by binding to the ACE2 receptor, viral RNA-dependent RNA polymerase (RdRp) and 3-chymotrypsin-like main protease (3Clpro/Mpro). Under the pressure of the accelerating COVID-19 pandemic caused by the outbreak of SARS-CoV-2 in Wuhan, China in December 2019, novel and repurposed drugs were recently designed and identified for targeting the SARS-CoV-2 reproduction machinery, with the aim to limit the spread of SARS-CoV-2 and morbidity and mortality due to the COVID-19 pandemic.
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Affiliation(s)
- Ariane Sternberg
- Center and Network for Targeted Oncology, Muehlackerweg 8, D-69239 Heidelberg, Germany
| | | | - Cord Naujokat
- Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg, Germany
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48
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Sofosbuvir and Ribavirin Combination Therapy Response in Various Hepatitis C Virus Genotypes in Peshawar, Khyber Pakhtunkhwa. Jundishapur J Microbiol 2020. [DOI: 10.5812/jjm.99625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Background: Approximately 3% of the population worldwide is infected with Hepatitis C Virus (HCV). Different regimens have been used to treat HCV, each of which has its side effects and efficacy. Sofosbuvir, a direct-acting antiviral drug, has replaced all previous regimens with the highest response rate. However, its response is not fully covered in Pakistan, especially Khyber Pakhtunkhwa. Objectives: The study aimed to examine the response to Sofosbuvir and Ribavirin combination therapy in chronic HCV patients infected with various HCV genotypes. Methods: This study was conducted in Tertiary Care Hospitals, Peshawar, Pakistan. The patients were enrolled from January 2016 to March 2017. A total of 80 patients (57 naïve and 23 non-responder) were enrolled in this study. The age range was 16 - 70 years, and the mean age was 36 ± 2 years. Genotyping, biochemical profile, PCR tests, and liver ultrasounds were done for all of the enrolled subjects at the start and end of therapy. All patients were given direct-acting antiviral drugs for six months and then, the end of treatment response was noted. Results: A total of 80 subjects with HCV infection took part in the study, including 57 (71.25%) treatment-naïve and 23 (28.75%) treatment non-responding patients. The end of therapy response was reported after 24 weeks of treatment. Among the 80 patients, 72 (90%) patients achieved the end of therapy response. The highest end of therapy response (100%) was noted in genotype 1 and mixed genotypes and patients with normal liver ultrasound. The lowest end of therapy response (70%) was found in un-type genotype and patients with an abnormal texture of liver ultrasound. The end of therapy response rate was higher in females than in males. Conclusions: In the current study, the minimal response was found in un-type genotypes and genotypes that did not respond to INF, as compared to treatment-naïve subjects. Further research is needed to understand the relevant host and viral factors, with particular attention to relapsed patients and non-responders that are difficult to treat in the Pakistani population.
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In vitro translation of virally-encoded replication polyproteins to recapitulate polyprotein maturation processes. Protein Expr Purif 2020; 175:105694. [PMID: 32681958 DOI: 10.1016/j.pep.2020.105694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 11/21/2022]
Abstract
Single-stranded, positive-sense RNA viruses encode essential replication polyproteins which are composed of several domains. They are usually subjected to finely regulated proteolytic maturation processes to generate cleavage intermediates and end-products. Both polyproteins and maturation products play multiple key roles that ultimately allow synthesis of viral genome progeny. Despite the importance of these proteins in the course of viral replication, their structural properties, including the conformational changes regulating their numerous functions, are poorly described at the structural level. This lack of information is mainly due to the extreme difficulty to express large, membrane-bound, multi-domain proteins with criteria suitable for structural biology methods. To tackle this challenge, we have used a wheat-germ cell-free expression system. We firstly establish that this approach allows to synthesize viral polyproteins encoded by two unrelated positive-sense RNA viruses, a human norovirus and a plant tymovirus. Then, we demonstrate that these polyproteins are fully functional and are spontaneously auto-cleaved by their active protease domain, giving rise to natural maturation products. Moreover, we show that introduction of point mutations in polyproteins allows to inhibit the proteolytic maturation process of each virus. This allowed us to express and partially purify the uncleaved full-length norovirus polyprotein and the tymoviral RNA-dependent RNA polymerase. Thus, this study provides a powerful tool to obtain soluble viral polyproteins and their maturation products in order to conduct challenging structural biology projects and therefore solve unanswered questions.
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50
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Martínez JL, Arias CF. Role of the Guanine Nucleotide Exchange Factor GBF1 in the Replication of RNA Viruses. Viruses 2020; 12:E682. [PMID: 32599855 PMCID: PMC7354614 DOI: 10.3390/v12060682] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/06/2020] [Accepted: 04/06/2020] [Indexed: 12/12/2022] Open
Abstract
The guanine nucleotide exchange factor GBF1 is a well-known factor that can activate different ADP-ribosylation factor (Arf) proteins during the regulation of different cellular vesicular transport processes. In the last decade, it has become increasingly evident that GBF1 can also regulate different steps of the replication cycle of RNA viruses belonging to different virus families. GBF1 has been shown not only to facilitate the intracellular traffic of different viral and cellular elements during infection, but also to modulate the replication of viral RNA, the formation and maturation of viral replication complexes, and the processing of viral proteins through mechanisms that do not depend on its canonical role in intracellular transport. Here, we review the various roles that GBF1 plays during the replication of different RNA viruses.
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Affiliation(s)
| | - Carlos F. Arias
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 4510, Morelos, Mexico;
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