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Moustafa RI, Dubuisson J, Lavie M. Function of the HCV E1 envelope glycoprotein in viral entry and assembly. Future Virol 2019. [DOI: 10.2217/fvl-2018-0180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
HCV envelope glycoproteins, E1 and E2, are multifunctional proteins. Until recently, E2 glycoprotein was thought to be the fusion protein and was the focus of investigations. However, the recently obtained partial structures of E2 and E1 rather support a role for E1 alone or in association with E2 in HCV fusion. Moreover, they suggest that HCV harbors a new fusion mechanism, distinct from that of other members of the Flaviviridae family. In this context, E1 aroused a renewed interest. Recent functional characterizations of E1 revealed a more important role than previously thought in entry and assembly. Thus, E1 is involved in the viral genome encapsidation step and influences the association of the virus with lipoprotein components. Moreover, E1 modulates HCV–receptor interaction and participates in a late entry step potentially fusion. In this review, we outline our current knowledge on E1 functions in HCV assembly and entry.
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Affiliation(s)
- Rehab I Moustafa
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – CIIL– Centre d'Infection et d'Immunité de Lille, F-59000 Lille, France
- Department of Microbial Biotechnology, Genetic Engineering & Biotechnology Division, National Research Center, Dokki, Cairo, Egypt
| | - Jean Dubuisson
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – CIIL– Centre d'Infection et d'Immunité de Lille, F-59000 Lille, France
| | - Muriel Lavie
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – CIIL– Centre d'Infection et d'Immunité de Lille, F-59000 Lille, France
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2
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Tong Y, Lavillette D, Li Q, Zhong J. Role of Hepatitis C Virus Envelope Glycoprotein E1 in Virus Entry and Assembly. Front Immunol 2018; 9:1411. [PMID: 29971069 PMCID: PMC6018474 DOI: 10.3389/fimmu.2018.01411] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/06/2018] [Indexed: 12/22/2022] Open
Abstract
Hepatitis C virus (HCV) glycoproteins E1 and E2 form a heterodimer to constitute viral envelope proteins, which play an essential role in virus entry. E1 does not directly interact with host receptors, and its functions in viral entry are exerted mostly through its interaction with E2 that directly binds the receptors. HCV enters the host cell via receptor-mediated endocytosis during which the fusion of viral and host endosomal membranes occurs to release viral genome to cytoplasm. A putative fusion peptide in E1 has been proposed to participate in membrane fusion, but its exact role and underlying molecular mechanisms remain to be deciphered. Recently solved crystal structures of the E2 ectodomains and N-terminal of E1 fail to reveal a classical fusion-like structure in HCV envelope glycoproteins. In addition, accumulating evidence suggests that E1 also plays an important role in virus assembly. In this mini-review, we summarize current knowledge on HCV E1 including its structure and biological functions in virus entry, fusion, and assembly, which may provide clues for developing HCV vaccines and more effective antivirals.
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Affiliation(s)
- Yimin Tong
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Dimitri Lavillette
- Unit of Interspecies Transmission of Arboviruses and Antivirals, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Qingchao Li
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jin Zhong
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
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Visualizing the Essential Role of Complete Virion Assembly Machinery in Efficient Hepatitis C Virus Cell-to-Cell Transmission by a Viral Infection-Activated Split-Intein-Mediated Reporter System. J Virol 2017; 91:JVI.01720-16. [PMID: 27852847 DOI: 10.1128/jvi.01720-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/07/2016] [Indexed: 12/29/2022] Open
Abstract
Hepatitis C virus (HCV) infects 2 to 3% of the world population and is a leading cause of liver diseases such as fibrosis, cirrhosis, and hepatocellular carcinoma. Many aspects of HCV study, ranging from molecular virology and antiviral drug development to drug resistance profiling, were supported by straightforward assays of HCV replication and infection. Among these assays, the HCV-dependent fluorescence relocalization (HDFR) system allowed live-cell visualization of infection without modifying the viral genome, but this strategy required careful recognition of the fluorescence relocalization pattern for its high fluorescence background in the cytoplasm. In this study, to achieve background-free visualization of HCV infection, a viral infection-activated split-intein-mediated reporter system (VISI) was devised. Uninfected Huh7.5.1-VISI cells show no background signal, while HCV infection specifically illuminates the nuclei of infected Huh7.5.1-VISI cells with either green fluorescent protein (GFP) or mCherry. Combining VISI-GFP and VISI-mCherry systems, we revisited HCV cell-to-cell transmission with clear-cut distinction of donor and recipient cells in a live-cell manner. Independently of virion assembly, exosomes have been reported to transfer HCV subgenomic RNA to initiate replication in uninfected cells, which suggested an assembly-free pathway. However, our data demonstrated that HCV structural genes and the p7 gene were essential for not only cell-free infectivity but also cell-to-cell transmission. Additionally, depletion of apolipoprotein E (ApoE) from donor cells but not from recipient cells significantly reduced HCV cell-to-cell transmission efficiency. In summary, we developed a background-free cell-based reporter system for convenient live-cell visualization of HCV infection, and our data indicate that complete HCV virion assembly machinery is essential for both cell-free and cell-to-cell transmission. IMPORTANCE Hepatitis C virus (HCV) infects hepatocytes via two pathways: cell-free infection and cell-to-cell transmission. Structural modules of the HCV genome are required for production of infectious cell-free virions; however, the role of specific genes within the structural module in cell-to-cell transmission is not clearly defined. Our data demonstrate that deletion of core, E1E2, and p7 genes individually results in no HCV cell-to-cell transmission and that ApoE knockdown from donor cells causes less-efficient cell-to-cell transmission. Thus, this work indicates that the complete HCV assembly machinery is required for HCV cell-to-cell transmission. At last, this work presents an optimized viral infection-activated split-intein-mediated reporter system for easy live-cell monitoring of HCV infection.
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Lacour W, Adjili S, Blaising J, Favier A, Monier K, Mezhoud S, Ladavière C, Place C, Pécheur EI, Charreyre MT. Far-Red Fluorescent Lipid-Polymer Probes for an Efficient Labeling of Enveloped Viruses. Adv Healthc Mater 2016; 5:2032-44. [PMID: 27113918 PMCID: PMC7159338 DOI: 10.1002/adhm.201600091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/25/2016] [Indexed: 12/13/2022]
Abstract
Far-red emitting fluorescent lipid probes are desirable to label enveloped viruses, for their efficient tracking by optical microscopy inside autofluorescent cells. Most used probes are rapidly released from membranes, leading to fluorescence signal decay and loss of contrast. Here, water-soluble lipid-polymer probes are synthesized harboring hydrophilic or hydrophobic far-red emitting dyes, and exhibiting enhanced brightness. They efficiently label Hepatitis C Virus pseudotyped particles (HCVpp), more stably and reproducibly than commercial probes, and a strong fluorescence signal is observed with a high contrast. Labeling with such probes do not alter virion morphology, integrity, nor infectivity. Finally, it is shown by fluorescence microscopy that these probes enable efficient tracking of labeled HCVpp inside hepatocarcinoma cells used as model hepatocytes, in spite of their autofluorescence up to 700 nm. These novel fluorescent lipid-polymer probes should therefore enable a better characterization of early stages of infection of autofluorescent cells by enveloped viruses.
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Affiliation(s)
- William Lacour
- Université Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, F-69342, Lyon, France
- Université Lyon, INSA Lyon, Université Claude Bernard, CNRS, Laboratoire Ingénierie des Matériaux Polymères, F-69621, Villeurbanne, France
| | - Salim Adjili
- Université Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, F-69342, Lyon, France
- Université Lyon, INSA Lyon, Université Claude Bernard, CNRS, Laboratoire Ingénierie des Matériaux Polymères, F-69621, Villeurbanne, France
| | - Julie Blaising
- Université Lyon, Univ Claude Bernard, INSERM U1052, CNRS 5286, Centre de Recherche en Cancérologie de Lyon (CRCL), F-69424, Lyon, France
| | - Arnaud Favier
- Université Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, F-69342, Lyon, France
- Université Lyon, INSA Lyon, Université Claude Bernard, CNRS, Laboratoire Ingénierie des Matériaux Polymères, F-69621, Villeurbanne, France
| | - Karine Monier
- Université Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, F-69342, Lyon, France
| | - Sarra Mezhoud
- Université Lyon, INSA Lyon, Université Claude Bernard, CNRS, Laboratoire Ingénierie des Matériaux Polymères, F-69621, Villeurbanne, France
| | - Catherine Ladavière
- Université Lyon, INSA Lyon, Université Claude Bernard, CNRS, Laboratoire Ingénierie des Matériaux Polymères, F-69621, Villeurbanne, France
| | - Christophe Place
- Université Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, F-69342, Lyon, France
- Université Lyon, Ens de Lyon, Université Claude Bernard, CNRS, Laboratoire de Physique, F-69342, Lyon, France
| | - Eve-Isabelle Pécheur
- Université Lyon, Univ Claude Bernard, INSERM U1052, CNRS 5286, Centre de Recherche en Cancérologie de Lyon (CRCL), F-69424, Lyon, France
| | - Marie-Thérèse Charreyre
- Université Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, F-69342, Lyon, France
- Université Lyon, INSA Lyon, Université Claude Bernard, CNRS, Laboratoire Ingénierie des Matériaux Polymères, F-69621, Villeurbanne, France
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El-Araby AM, Fouad AA, Hanbal AM, Abdelwahab SM, Qassem OM, El-Araby ME. Epigenetic Pathways of Oncogenic Viruses: Therapeutic Promises. Arch Pharm (Weinheim) 2016; 349:73-90. [PMID: 26754591 DOI: 10.1002/ardp.201500375] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 11/30/2015] [Accepted: 12/04/2015] [Indexed: 01/19/2023]
Abstract
Cancerous transformation comprises different events that are both genetic and epigenetic. The ultimate goal for such events is to maintain cell survival and proliferation. This transformation occurs as a consequence of different features such as environmental and genetic factors, as well as some types of infection. Many viral infections are considered to be causative agents of a number of different malignancies. To convert normal cells into cancerous cells, oncogenic viruses must function at the epigenetic level to communicate with their host cells. Oncogenic viruses encode certain epigenetic factors that lead to the immortality and proliferation of infected cells. The epigenetic effectors produced by oncogenic viruses constitute appealing targets to prevent and treat malignant diseases caused by these viruses. In this review, we highlight the importance of epigenetic reprogramming for virus-induced oncogenesis, with special emphasis on viral epigenetic oncoproteins as therapeutic targets. The discovery of molecular components that target epigenetic pathways, especially viral factors, is also discussed.
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Affiliation(s)
- Amr M El-Araby
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | | | - Amr M Hanbal
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | | | - Omar M Qassem
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | - Moustafa E El-Araby
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Alsulaymanya, Jeddah, Saudi Arabia.,Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Helwan University, Cairo, Egypt
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