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Khalfi P, Denis Z, McKellar J, Merolla G, Chavey C, Ursic-Bedoya J, Soppa L, Szirovicza L, Hetzel U, Dufourt J, Leyrat C, Goldmann N, Goto K, Verrier E, Baumert TF, Glebe D, Courgnaud V, Gregoire D, Hepojoki J, Majzoub K. Comparative analysis of human, rodent and snake deltavirus replication. PLoS Pathog 2024; 20:e1012060. [PMID: 38442126 PMCID: PMC10942263 DOI: 10.1371/journal.ppat.1012060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 03/15/2024] [Accepted: 02/19/2024] [Indexed: 03/07/2024] Open
Abstract
The recent discovery of Hepatitis D (HDV)-like viruses across a wide range of taxa led to the establishment of the Kolmioviridae family. Recent studies suggest that kolmiovirids can be satellites of viruses other than Hepatitis B virus (HBV), challenging the strict HBV/HDV-association dogma. Studying whether kolmiovirids are able to replicate in any animal cell they enter is essential to assess their zoonotic potential. Here, we compared replication of three kolmiovirids: HDV, rodent (RDeV) and snake (SDeV) deltavirus in vitro and in vivo. We show that SDeV has the narrowest and RDeV the broadest host cell range. High resolution imaging of cells persistently replicating these viruses revealed nuclear viral hubs with a peculiar RNA-protein organization. Finally, in vivo hydrodynamic delivery of viral replicons showed that both HDV and RDeV, but not SDeV, efficiently replicate in mouse liver, forming massive nuclear viral hubs. Our comparative analysis lays the foundation for the discovery of specific host factors controlling Kolmioviridae host-shifting.
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Affiliation(s)
- Pierre Khalfi
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Zoé Denis
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Joe McKellar
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Giovanni Merolla
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Carine Chavey
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - José Ursic-Bedoya
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
- Department of hepato-gastroenterology, Hepatology and Liver Transplantation Unit, Saint Eloi University Hospital, Montpellier, France
| | - Lena Soppa
- Institute of Medical Virology, National Reference Centre for Hepatitis B Viruses and Hepatitis D Viruses, German Center for Infection Research (DZIF, Partner Site Giessen-Marburg-Langen), Justus Liebig University Giessen, Giessen, Germany
| | - Leonora Szirovicza
- Medicum, Department of Virology, University of Helsinki, Helsinki, Finland
| | - Udo Hetzel
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Jeremy Dufourt
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR9004, Montpellier, France
| | - Cedric Leyrat
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Nora Goldmann
- Institute of Medical Virology, National Reference Centre for Hepatitis B Viruses and Hepatitis D Viruses, German Center for Infection Research (DZIF, Partner Site Giessen-Marburg-Langen), Justus Liebig University Giessen, Giessen, Germany
| | - Kaku Goto
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
- Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Nouvel Hôpital Civil, Strasbourg, France
| | - Eloi Verrier
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
- Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Nouvel Hôpital Civil, Strasbourg, France
| | - Thomas F. Baumert
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
- Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Nouvel Hôpital Civil, Strasbourg, France
| | - Dieter Glebe
- Institute of Medical Virology, National Reference Centre for Hepatitis B Viruses and Hepatitis D Viruses, German Center for Infection Research (DZIF, Partner Site Giessen-Marburg-Langen), Justus Liebig University Giessen, Giessen, Germany
| | - Valérie Courgnaud
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Damien Gregoire
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Jussi Hepojoki
- Medicum, Department of Virology, University of Helsinki, Helsinki, Finland
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Karim Majzoub
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
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2
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Maestro S, Gomez-Echarte N, Camps G, Usai C, Olagüe C, Vales A, Aldabe R, Gonzalez-Aseguinolaza G. Deciphering the Role of Post-Translational Modifications and Cellular Location of Hepatitis Delta Virus (HDV) Antigens in HDV-Mediated Liver Damage in Mice. Viruses 2024; 16:379. [PMID: 38543745 PMCID: PMC10975000 DOI: 10.3390/v16030379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/20/2024] [Accepted: 02/26/2024] [Indexed: 05/23/2024] Open
Abstract
Hepatitis D virus (HDV) infection represents the most severe form of chronic viral hepatitis. We have shown that the delivery of HDV replication-competent genomes to the hepatocytes using adeno-associated virus (AAV-HDV) as gene delivery vehicles offers a unique platform to investigate the molecular aspects of HDV and associated liver damage. For the purpose of this study, we generated HDV genomes modified by site-directed mutagenesis aimed to (i) prevent some post-translational modifications of HDV antigens (HDAgs) such as large-HDAg (L-HDAg) isoprenylation or short-HDAg (S-HDAg) phosphorylation; (ii) alter the localization of HDAgs within the subcellular compartments; and (iii) inhibit the right conformation of the delta ribozyme. First, the different HDV mutants were tested in vitro using plasmid-transfected Huh-7 cells and then in vivo in C57BL/6 mice using AAV vectors. We found that Ser177 phosphorylation and ribozymal activity are essential for HDV replication and HDAg expression. Mutations of the isoprenylation domain prevented the formation of infectious particles and increased cellular toxicity and liver damage. Furthermore, altering HDAg intracellular localization notably decreased viral replication, though liver damage remained unchanged versus normal HDAg distribution. In addition, a mutation in the nuclear export signal impaired the formation of infectious viral particles. These findings contribute valuable insights into the intricate mechanisms of HDV biology and have implications for therapeutic considerations.
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Affiliation(s)
- Sheila Maestro
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
- IdiSNA—Instituto de Investigación Sanitaria de Navarra, 31008 Pamplona, Spain
| | - Nahia Gomez-Echarte
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
- IdiSNA—Instituto de Investigación Sanitaria de Navarra, 31008 Pamplona, Spain
| | - Gracian Camps
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
- IdiSNA—Instituto de Investigación Sanitaria de Navarra, 31008 Pamplona, Spain
| | - Carla Usai
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
- IdiSNA—Instituto de Investigación Sanitaria de Navarra, 31008 Pamplona, Spain
| | - Cristina Olagüe
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
| | - Africa Vales
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
| | - Rafael Aldabe
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
| | - Gloria Gonzalez-Aseguinolaza
- DNA & RNA Medicine Division, Centro de Investigación Médica Aplicada, University of Navarra, Avenida Pío XII, 31008 Pamplona, Spain; (S.M.); (N.G.-E.); (G.C.); (C.U.); (C.O.); (A.V.)
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3
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Heuschkel MJ, Bach C, Meiss-Heydmann L, Gerges E, Felli E, Giannone F, Pessaux P, Schuster C, Lucifora J, Baumert TF, Verrier ER. JAK1 promotes HDV replication and is a potential target for antiviral therapy. J Hepatol 2024; 80:220-231. [PMID: 37925078 DOI: 10.1016/j.jhep.2023.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 10/17/2023] [Accepted: 10/21/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND & AIMS Chronic co-infection with HBV and HDV leads to the most aggressive form of chronic viral hepatitis. To date, no treatment induces efficient viral clearance, and a better characterization of virus-host interactions is required to develop new therapeutic strategies. METHODS Using loss-of-function strategies, we validated the unexpected proviral activity of Janus kinase 1 (JAK1) - a key player in innate immunity - in the HDV life cycle and determined its mechanism of action on HDV through various functional analyses including co-immunoprecipitation assays. RESULTS We confirmed the key role of JAK1 kinase activity in HDV infection. Moreover, our results suggest that JAK1 inhibition is associated with a modulation of ERK1/2 activation and S-HDAg phosphorylation, which is crucial for viral replication. Finally, we showed that FDA-approved JAK1-specific inhibitors are efficient antivirals in relevant in vitro models including primary human hepatocytes. CONCLUSIONS Taken together, we uncovered JAK1 as a key host factor for HDV replication and a potential target for new antiviral treatment. IMPACT AND IMPLICATIONS Chronic hepatitis D is the most aggressive form of chronic viral hepatitis. As no curative treatment is currently available, new therapeutic strategies based on host-targeting agents are urgently needed. Here, using loss-of-function strategies, we uncover an unexpected interaction between JAK1, a major player in the innate antiviral response, and HDV infection. We demonstrated that JAK1 kinase activity is crucial for both the phosphorylation of the delta antigen and the replication of the virus. By demonstrating the antiviral potential of several FDA-approved JAK1 inhibitors, our results could pave the way for the development of innovative therapeutic strategies to tackle this global health threat.
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Affiliation(s)
- Margaux J Heuschkel
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
| | - Charlotte Bach
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
| | - Laura Meiss-Heydmann
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
| | - Emma Gerges
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
| | - Emanuele Felli
- Institut hospitalo-universitaire (IHU), Service d'hépato-gastroentérologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Fabio Giannone
- Institut hospitalo-universitaire (IHU), Service d'hépato-gastroentérologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Patrick Pessaux
- Institut hospitalo-universitaire (IHU), Service d'hépato-gastroentérologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Catherine Schuster
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France
| | - Julie Lucifora
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Thomas F Baumert
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France; Institut hospitalo-universitaire (IHU), Service d'hépato-gastroentérologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France; Institut Universitaire de France, Paris, France
| | - Eloi R Verrier
- Université de Strasbourg, Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMR_S1110, Strasbourg, France.
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4
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Thiyagarajah K, Basic M, Hildt E. Cellular Factors Involved in the Hepatitis D Virus Life Cycle. Viruses 2023; 15:1687. [PMID: 37632029 PMCID: PMC10459925 DOI: 10.3390/v15081687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/30/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023] Open
Abstract
Hepatitis D virus (HDV) is a defective RNA virus with a negative-strand RNA genome encompassing less than 1700 nucleotides. The HDV genome encodes only for one protein, the hepatitis delta antigen (HDAg), which exists in two forms acting as nucleoproteins. HDV depends on the envelope proteins of the hepatitis B virus as a helper virus for packaging its ribonucleoprotein complex (RNP). HDV is considered the causative agent for the most severe form of viral hepatitis leading to liver fibrosis/cirrhosis and hepatocellular carcinoma. Many steps of the life cycle of HDV are still enigmatic. This review gives an overview of the complete life cycle of HDV and identifies gaps in knowledge. The focus is on the description of cellular factors being involved in the life cycle of HDV and the deregulation of cellular pathways by HDV with respect to their relevance for viral replication, morphogenesis and HDV-associated pathogenesis. Moreover, recent progress in antiviral strategies targeting cellular structures is summarized in this article.
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Affiliation(s)
| | | | - Eberhard Hildt
- Paul-Ehrlich-Institute, Department of Virology, D-63225 Langen, Germany; (K.T.); (M.B.)
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5
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Khalfi P, Kennedy PT, Majzoub K, Asselah T. Hepatitis D virus: Improving virological knowledge to develop new treatments. Antiviral Res 2023; 209:105461. [PMID: 36396025 DOI: 10.1016/j.antiviral.2022.105461] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 10/21/2022] [Accepted: 11/05/2022] [Indexed: 11/16/2022]
Abstract
Hepatitis delta virus (HDV), a satellite of hepatitis B virus (HBV), possesses the smallest viral genome known to infect animals. HDV needs HBV surface protein for secretion and entry into target liver cells. However, HBV is dispensable for HDV genome amplification, as it relies almost exclusively on cellular host factors for replication. HBV/HDV co-infections affect over 12 million people worldwide and constitute the most severe form of viral hepatitis. Co-infected individuals are at higher risk of developing liver cirrhosis and hepatocellular carcinoma compared to HBV mono-infected patients. Bulevirtide, an entry inhibitor, was conditionally approved in July 2020 in the European Union for adult patients with chronic hepatitis delta (CHD) and compensated liver disease. There are several drugs in development, including lonafarnib and interferon lambda, with different modes of action. In this review, we detail our current fundamental knowledge of HDV lifecycle and review antiviral treatments under development against this virus, outlining their respective mechanisms-of-action. Finally, we describe the antiviral effect these compounds are showing in ongoing clinical trials, discussing their promise and potential pitfalls for managing HDV infected patients.
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Affiliation(s)
- Pierre Khalfi
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier 34293 cedex 5, France
| | - Patrick T Kennedy
- The Blizard Institute, Queen Mary University of London, The Royal London Hospital, Barts Health NHS Trust, London, UK
| | - Karim Majzoub
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier 34293 cedex 5, France.
| | - Tarik Asselah
- Université de Paris, Cité CRI, INSERM UMR 1149, Department of Hepatology, AP-HP Hôpital Beaujon, Clichy, France.
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6
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Zi J, Gao X, Du J, Xu H, Niu J, Chi X. Multiple Regions Drive Hepatitis Delta Virus Proliferation and Are Therapeutic Targets. Front Microbiol 2022; 13:838382. [PMID: 35464929 PMCID: PMC9022428 DOI: 10.3389/fmicb.2022.838382] [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: 12/17/2021] [Accepted: 03/11/2022] [Indexed: 12/02/2022] Open
Abstract
Hepatitis Delta Virus (HDV) is the smallest mammalian single-stranded RNA virus. It requires host cells and hepatitis B virus (HBV) to complete its unique life cycle. The present review summarizes the specific regions on hepatitis D antigen (HDAg) and hepatitis B surface antigen (HBsAg) that drive HDV to utilize host cell machinery system to produce three types of RNA and two forms of HDAg, and hijack HBsAg for its secretion and de novo entry. Previously, interferon-α was the only recommended therapy for HDV infection. In recent years, some new therapies targeting these regions, such as Bulevirtide, Lonafarnib, Nucleic acid polymers have appeared, with better curative effects and fewer adverse reactions.
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Affiliation(s)
- Jun Zi
- Gene Therapy Laboratory, Center for Pathogen Biology and Infectious Diseases, First Hospital of Jilin University, Changchun, China
| | - Xiuzhu Gao
- Department of Hepatology, Center for Pathogen Biology and Infectious Diseases, First Hospital of Jilin University, Changchun, China
| | - Juan Du
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, China
| | - Hongqin Xu
- Department of Hepatology, Center for Pathogen Biology and Infectious Diseases, First Hospital of Jilin University, Changchun, China
| | - Junqi Niu
- Department of Hepatology, Center for Pathogen Biology and Infectious Diseases, First Hospital of Jilin University, Changchun, China
| | - Xiumei Chi
- Gene Therapy Laboratory, Center for Pathogen Biology and Infectious Diseases, First Hospital of Jilin University, Changchun, China
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7
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Shirazi R, Ram D, Rakovsky A, Bucris E, Gozlan Y, Lustig Y, Shaked-Mishan P, Picard O, Shemer-Avni Y, Ben-Zvi H, Halutz O, Lurie Y, Veizman E, Carlebach M, Braun M, Naftaly MC, Shlomai A, Safadi R, Mendelson E, Sklan EH, Ben-Ari Z, Mor O. Characterization of hepatitis B and delta coinfection in Israel. BMC Infect Dis 2018; 18:97. [PMID: 29486716 PMCID: PMC6389180 DOI: 10.1186/s12879-018-3008-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/21/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Characteristics of hepatitis B (HBV) and delta (HDV) coinfection in various geographical regions, including Israel, remain unclear. Here we studied HDV seroprevalence in Israel, assessed HDV/HBV viral loads, circulating genotypes and hepatitis delta antigen (HDAg) conservation. METHODS Serological anti HDV IgG results from 8969 HBsAg positive individuals tested in 2010-2015 were retrospectively analyzed to determine HDV seroprevalence. In a cohort of HBV/HDV coinfected (n=58) and HBV monoinfected (n=27) patients, quantitative real-time PCR (qRT-PCR) and sequencing were performed to determine viral loads, genotypes and hepatitis delta antigen (HDAg) protein sequence. RESULTS 6.5% (587/8969) of the HBsAg positive patients were positive for anti HDV antibodies. HDV viral load was >2 log copies/ml higher than HBV viral load in most of the coinfected patients with detectable HDV RNA (86%, 50/58). HDV genotype 1 was identified in all patients, most of whom did not express HBV. While 66.6% (4/6) of the HBV/HDV co-expressing patients carried HBV-D2 only 18.5% (5/27) of the HBV monoinfections had HBV-D2 (p=0.03). Higher genetic variability in the HDAg protein sequence was associated with higher HDV viral load. CONCLUSIONS The overall significant prevalence of HDV (6.5%) mandates HDV RNA testing for all coinfected patients. Patients positive for HDV RNA (characterized by low HBV DNA blood levels) carried HDV genotype 1. Taken together, the significant HDV seroprevalence and the lack of effective anti-HDV therapy, necessitates strict clinical surveillance especially in patients with higher HDV viral loads and increased viral evolution.
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Affiliation(s)
- Rachel Shirazi
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel
| | - Daniela Ram
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel
| | - Aviya Rakovsky
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel
| | - Efrat Bucris
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel
| | - Yael Gozlan
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel
| | - Yaniv Lustig
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel
| | | | - Orit Picard
- Gastroenterology Laboratory, Sheba Medical Center, Ramat Gan, Israel
| | - Yonat Shemer-Avni
- Laboratory of Clinical Virology, Soroka University Medical Center, Beer Sheva, Israel
| | - Haim Ben-Zvi
- Microbiology Laboratory, Rabin Medical Center, Petach Tikva, Israel
| | - Ora Halutz
- Microbiology Laboratory, Sorasky Medical Center, Tel Aviv, Israel
| | - Yoav Lurie
- Liver Unit, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Ella Veizman
- Liver Unit, Rambam Medical Center, Haifa, Israel
| | | | - Marius Braun
- Liver Institute, Rabin Medical Center, Petah-Tikva, Israel
| | | | - Amir Shlomai
- Liver Institute, Rabin Medical Center, Petah-Tikva, Israel.,The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rifaat Safadi
- Liver Unit, Hadassah Hebrew University Hospital, Jerusalem, Israel
| | - Ella Mendelson
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel.,School of Public Health, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ella H Sklan
- The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ziv Ben-Ari
- The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Liver Disease Center, Sheba Medical Center, Ramat Gan, Israel
| | - Orna Mor
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel - Hashomer, 52621, Ramat Gan, Israel. .,School of Public Health, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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8
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Botelho-Souza LF, Vasconcelos MPA, Dos Santos ADO, Salcedo JMV, Vieira DS. Hepatitis delta: virological and clinical aspects. Virol J 2017; 14:177. [PMID: 28903779 PMCID: PMC5597996 DOI: 10.1186/s12985-017-0845-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 09/05/2017] [Indexed: 02/06/2023] Open
Abstract
There are an estimated 400 million chronic carriers of HBV worldwide; between 15 and 20 million have serological evidence of exposure to HDV. Traditionally, regions with high rates of endemicity are central and northern Africa, the Amazon Basin, eastern Europe and the Mediterranean, the Middle East and parts of Asia. There are two types of HDV/HBV infection which are differentiated by the previous status infection by HBV for the individual. Individuals with acute HBV infection contaminated by HDV is an HDV/HBV co-infection, while individuals with chronic HBV infection contaminated by HDV represent an HDV/HBV super-infection. The appropriate treatment for chronic hepatitis delta is still widely discussed since it does not have an effective drug. Alpha interferon is currently the only licensed therapy for the treatment of chronic hepatitis D. The most widely used drug is pegylated interferon but only approximately 25% of patients maintain a sustained viral response after 1 year of treatment. The best marker of therapeutic success would be the clearance of HBsAg, but this data is rare in clinical practice. Therefore, the best way to predict a sustained virologic response is the maintenance of undetectable HDV RNA levels.
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Affiliation(s)
- Luan Felipo Botelho-Souza
- Laboratório de Virologia Molecular - FIOCRUZ - RONDÔNIA, Rua da Beira, 7671 - BR 364, Km 3,5 Bairro Lagoa, CEP: 76812, Porto Velho, RO, CEP: 76812-329, Brazil.
- Ambulatório de Hepatites Virais, Fundação Oswaldo Cruz Rondônia e Centro de Pesquisa em Medicina Tropical - CEPEM, Avenida Guaporé, 215, anexo Hospital CEMETRON, Agenor M de Carvalho, Porto Velho, RO, CEP: 76812-329, Brazil.
- Programa de Pós-Graduação em Biologia Experimental - PGBioExp, Rodovia Br-364, KM 9, CAMPUS UNIR, Porto Velho, RO, CEP: 76801-974, Brazil.
| | | | - Alcione de Oliveira Dos Santos
- Laboratório de Virologia Molecular - FIOCRUZ - RONDÔNIA, Rua da Beira, 7671 - BR 364, Km 3,5 Bairro Lagoa, CEP: 76812, Porto Velho, RO, CEP: 76812-329, Brazil
- Ambulatório de Hepatites Virais, Fundação Oswaldo Cruz Rondônia e Centro de Pesquisa em Medicina Tropical - CEPEM, Avenida Guaporé, 215, anexo Hospital CEMETRON, Agenor M de Carvalho, Porto Velho, RO, CEP: 76812-329, Brazil
- Programa de Pós-Graduação em Biologia Experimental - PGBioExp, Rodovia Br-364, KM 9, CAMPUS UNIR, Porto Velho, RO, CEP: 76801-974, Brazil
| | - Juan Miguel Villalobos Salcedo
- Laboratório de Virologia Molecular - FIOCRUZ - RONDÔNIA, Rua da Beira, 7671 - BR 364, Km 3,5 Bairro Lagoa, CEP: 76812, Porto Velho, RO, CEP: 76812-329, Brazil
- Ambulatório de Hepatites Virais, Fundação Oswaldo Cruz Rondônia e Centro de Pesquisa em Medicina Tropical - CEPEM, Avenida Guaporé, 215, anexo Hospital CEMETRON, Agenor M de Carvalho, Porto Velho, RO, CEP: 76812-329, Brazil
- Programa de Pós-Graduação em Biologia Experimental - PGBioExp, Rodovia Br-364, KM 9, CAMPUS UNIR, Porto Velho, RO, CEP: 76801-974, Brazil
| | - Deusilene Souza Vieira
- Laboratório de Virologia Molecular - FIOCRUZ - RONDÔNIA, Rua da Beira, 7671 - BR 364, Km 3,5 Bairro Lagoa, CEP: 76812, Porto Velho, RO, CEP: 76812-329, Brazil
- Ambulatório de Hepatites Virais, Fundação Oswaldo Cruz Rondônia e Centro de Pesquisa em Medicina Tropical - CEPEM, Avenida Guaporé, 215, anexo Hospital CEMETRON, Agenor M de Carvalho, Porto Velho, RO, CEP: 76812-329, Brazil
- Programa de Pós-Graduação em Biologia Experimental - PGBioExp, Rodovia Br-364, KM 9, CAMPUS UNIR, Porto Velho, RO, CEP: 76801-974, Brazil
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9
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A novel toolbox for the in vitro assay of hepatitis D virus infection. Sci Rep 2017; 7:40199. [PMID: 28079152 PMCID: PMC5228157 DOI: 10.1038/srep40199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/02/2016] [Indexed: 02/08/2023] Open
Abstract
Hepatitis D virus (HDV) is a defective RNA virus that requires the presence of hepatitis B virus (HBV) for its life cycle. The in vitro HDV infection system is widely used as a surrogate model to study cellular infection with both viruses owing to its practical feasibility. However, previous methods for running this system were less efficient for high-throughput screening and large-scale studies. Here, we developed a novel method for the production of infectious HDV by adenoviral vector (AdV)-mediated transduction. We demonstrated that the AdV-based method yields 10-fold higher viral titers than the transient-transfection approach. The HDV-containing supernatant derived from AdV-infected Huh7 cells can be used as the inoculum in infectivity assays without requiring further concentration prior to use. Furthermore, we devloped a chemiluminescent immunoassay (HDV-CLEIA) to quantitatively determine intracellular HDAg with a dynamic range of 5–11,000 pg/mL. HDV-CLEIA can be used as an alternative approach to assess HDV infection. The advantages of our updated methodology were demonstrated through in vitro HDV infection of HepaRG cells and by evaluating the neutralization activity using antibodies that target various regions of the HBV/HDV envelope proteins. Together, the methods presented here comprise a novel toolbox of in vitro assays for studying HDV infection.
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10
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Chao M, Lin CC, Lin FM, Li HP, Iang SB. Whole-genome analysis of genetic recombination of hepatitis delta virus: molecular domain in delta antigen determining trans-activating efficiency. J Gen Virol 2016; 96:3460-3469. [PMID: 26407543 DOI: 10.1099/jgv.0.000297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis delta virus (HDV) is the only animal RNA virus that has an unbranched rod-like genome with ribozyme activity and is replicated by host RNA polymerase. HDV RNA recombination was previously demonstrated in patients and in cultured cells by analysis of a region corresponding to the C terminus of the delta antigen (HDAg), the only viral-encoded protein. Here, a whole-genome recombination map of HDV was constructed using an experimental system in which two HDV-1 sequences were co-transfected into cultured cells and the recombinants were analysed by sequencing of cloned reverse transcription-PCR products. Fifty homologous recombinants with 60 crossovers mapping to 22 junctions were identified from 200 analysed clones. Small HDAg chimeras harbouring a junction newly detected in the recombination map were then constructed. The results further indicated that the genome-replication level of HDV was sensitive to the sixth amino acid within the N-terminal 22 aa of HDAg. Therefore, the recombination map established in this study provided a tool for not only understanding HDV RNA recombination, but also elucidating the related mechanisms, such as molecular elements responsible for the trans-activation levels of the small HDAg.
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Affiliation(s)
- Mei Chao
- Division of Microbiology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
- Department of Microbiology and Immunology, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
| | - Chia-Chi Lin
- Division of Microbiology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
| | - Feng-Ming Lin
- Division of Microbiology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
| | - Hsin-Pai Li
- Division of Microbiology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
- Department of Microbiology and Immunology, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
| | - Shan-Bei Iang
- Molecular Medicine Research Center, Chang Gung University, Guishan, Taoyuan 33302, Taiwan
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11
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Abstract
This work reviews specific related aspects of hepatitis delta virus (HDV) reproduction, including virion structure, the RNA genome, the mode of genome replication, the delta antigens, and the assembly of HDV using the envelope proteins of its helper virus, hepatitis B virus (HBV). These topics are considered with perspectives ranging from a history of discovery through to still-unsolved problems. HDV evolution, virus entry, and associated pathogenic potential and treatment of infections are considered in other articles in this collection.
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Affiliation(s)
- John M Taylor
- Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111
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12
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Huang CR, Lo SJ. Hepatitis D virus infection, replication and cross-talk with the hepatitis B virus. World J Gastroenterol 2014; 20:14589-14597. [PMID: 25356023 PMCID: PMC4209526 DOI: 10.3748/wjg.v20.i40.14589] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 05/12/2014] [Accepted: 06/23/2014] [Indexed: 02/06/2023] Open
Abstract
Viral hepatitis remains a worldwide public health problem. The hepatitis D virus (HDV) must either coinfect or superinfect with the hepatitis B virus (HBV). HDV contains a small RNA genome (approximately 1.7 kb) with a single open reading frame (ORF) and requires HBV supplying surface antigens (HBsAgs) to assemble a new HDV virion. During HDV replication, two isoforms of a delta antigen, a small delta antigen (SDAg) and a large delta antigen (LDAg), are produced from the same ORF of the HDV genome. The SDAg is required for HDV replication, whereas the interaction of LDAg with HBsAgs is crucial for packaging of HDV RNA. Various clinical outcomes of HBV/HDV dual infection have been reported, but the molecular interaction between HBV and HDV is poorly understood, especially regarding how HBV and HDV compete with HBsAgs for assembling virions. In this paper, we review the role of endoplasmic reticulum stress induced by HBsAgs and the molecular pathway involved in their promotion of LDAg nuclear export. Because the nuclear sublocalization and export of LDAg is regulated by posttranslational modifications (PTMs), including acetylation, phosphorylation, and isoprenylation, we also summarize the relationship among HBsAg-induced endoplasmic reticulum stress signaling, LDAg PTMs, and nuclear export mechanisms in this review.
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13
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Huang CR, Wang RYL, Hsu SC, Lo SJ. Lysine-71 in the large delta antigen of hepatitis delta virus clade 3 modulates its localization and secretion. Virus Res 2012; 170:75-84. [PMID: 23022530 DOI: 10.1016/j.virusres.2012.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/30/2012] [Accepted: 08/30/2012] [Indexed: 12/18/2022]
Abstract
Hepatitis delta virus (HDV) is an RNA virus and eight clades of HDV have been identified. HDV clade 3 (HDV-3) is isolated only in the northern area of South America. The outcome of HDV-3 infection is associated with severe fulminant hepatitis. Variations in the large delta antigen (LDAg) between HDV clade 1 (HDV-1) and HDV-3 have been proposed to contribute to differences in viral secretion efficiency, but which changes might be relevant remains unclear. The control of subcellular localization of LDAg has been reported to be associated with post-translational modifications, such as phosphorylation and isoprenylation. We have observed evidence for acetylation on the LDAg of HDV-3 (LDAg-3) and LDAg of HDV-1 (LDAg-1). Green fluorescent protein-fused LDAg-3 (GFP-LD3) was used to investigate the cellular distribution and secretion of the protein. Sequence alignment of LDAg amino acids suggested that lysine-71 of LDAg-3 could be an acetylation site. Expression of a mutant form of LDAg-3 with an arginine-substitution at lysine-71 (GFP-LD3K71R) showed a distribution of the protein predominantly in the cytoplasm instead of the nucleus. Western blot analyses of secreted empty viral particles (EVPs) revealed a higher amount of secreted GFP-LD3K71R compared to GFP-LD3. Furthermore, the ectopic expression of p300, a histone acetyltransferase, led to a reduction of GFP-LD3 in EVPs. By contrast, expression of three histone deacetylases (HDAC-4, -5, and -6) facilitated the secretion of GFP-LD3. Combined, our observations support the hypothesis that the acetylation status of LDAg-3 plays a role in regulating LDAg-3's localization inside the nucleus or cytoplasm, and its secretion.
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Affiliation(s)
- Chi-Ruei Huang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, ROC
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14
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Interaction of host cellular proteins with components of the hepatitis delta virus. Viruses 2010; 2:189-212. [PMID: 21994607 PMCID: PMC3185554 DOI: 10.3390/v2010189] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 01/13/2010] [Accepted: 01/14/2010] [Indexed: 12/18/2022] Open
Abstract
The hepatitis delta virus (HDV) is the smallest known RNA pathogen capable of propagation in the human host and causes substantial global morbidity and mortality. Due to its small size and limited protein coding capacity, HDV is exquisitely reliant upon host cellular proteins to facilitate its transcription and replication. Remarkably, HDV does not encode an RNA-dependent RNA polymerase which is traditionally required to catalyze RNA-templated RNA synthesis. Furthermore, HDV lacks enzymes responsible for post-transcriptional and -translational modification, processes which are integral to the HDV life cycle. This review summarizes the known HDV-interacting proteins and discusses their significance in HDV biology.
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15
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Phosphorylation of serine 177 of the small hepatitis delta antigen regulates viral antigenomic RNA replication by interacting with the processive RNA polymerase II. J Virol 2009; 84:1430-8. [PMID: 19923176 DOI: 10.1128/jvi.02083-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Recent studies revealed that posttranslational modifications (e.g., phosphorylation and methylation) of the small hepatitis delta antigen (SHDAg) are required for hepatitis delta virus (HDV) replication from antigenomic to genomic RNA. The phosphorylation of SHDAg at serine 177 (Ser(177)) is involved in this step, and this residue is crucial for interaction with RNA polymerase II (RNAP II), the enzyme assumed to be responsible for antigenomic RNA replication. This study demonstrated that SHDAg dephosphorylated at Ser(177) interacted preferentially with hypophosphorylated RNAP II (RNAP IIA), which generally binds at the transcription initiation sites. In contrast, the Ser(177)-phosphorylated counterpart (pSer(177)-SHDAg) exhibited preferential binding to hyperphosphorylated RNAP II (RNAP IIO). In addition, RNAP IIO associated with pSer(177)-SHDAg was hyperphosphorylated at both the Ser(2) and Ser(5) residues of its carboxyl-terminal domain (CTD), which is a hallmark of the transcription elongation isoform. Moreover, the RNAP II CTD kinase inhibitor 5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole (DRB) not only blocked the interaction between pSer(177)-SHDAg and RNAP IIO but also inhibited HDV antigenomic RNA replication. Our results suggest that the phosphorylation of SHDAg at Ser177 shifted its affinitytoward the RNAP IIO isoform [corrected] and thus is a switch for HDV antigenomic RNA replication from the initiation to the elongation stage.
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16
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Hepatitis delta virus RNA replication. Viruses 2009; 1:818-31. [PMID: 21994571 PMCID: PMC3185533 DOI: 10.3390/v1030818] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/03/2009] [Accepted: 11/03/2009] [Indexed: 12/12/2022] Open
Abstract
Hepatitis delta virus (HDV) is a distant relative of plant viroids in the animal world. Similar to plant viroids, HDV replicates its circular RNA genome using a double rolling-circle mechanism. Nevertheless, the production of hepatitis delta antigen (HDAg), which is indispensible for HDV replication, is a unique feature distinct from plant viroids, which do not encode any protein. Here the HDV RNA replication cycle is reviewed, with emphasis on the function of HDAg in modulating RNA replication and the nature of the enzyme involved.
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17
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Abstract
Hepatitis delta antigen (HDAg) is a nuclear protein that is intimately involved in hepatitis delta virus (HDV) RNA replication. HDAg consists of two protein species, the small form (S-HDAg) and the large form (L-HDAg). Previous studies have shown that posttranslational modifications of S-HDAg, such as phosphorylation, acetylation, and methylation, can modulate HDV RNA replication. In this study, we show that S-HDAg is a small ubiquitin-like modifier 1 (SUMO1) target protein. Mapping data showed that multiple lysine residues are SUMO1 acceptors within S-HDAg. Using a genetic fusion strategy, we found that conjugation of SUMO1 to S-HDAg selectively enhanced HDV genomic RNA and mRNA synthesis but not antigenomic RNA synthesis. This result supports our previous proposition that the cellular machinery involved in the synthesis of HDV antigenomic RNA is different from that for genomic RNA synthesis and mRNA transcription, requiring different modified forms of S-HDAg. Sumoylation represents a new type of modification for HDAg.
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18
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Transcription of subgenomic mRNA of hepatitis delta virus requires a modified hepatitis delta antigen that is distinct from antigenomic RNA synthesis. J Virol 2008; 82:9409-16. [PMID: 18653455 DOI: 10.1128/jvi.00428-08] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis delta virus (HDV) contains a viroid-like, 1.7-kb circular RNA genome, which replicates via a double-rolling-circle model. However, the exact mechanism involved in HDV genome RNA replication and subgenomic mRNA transcription is still unclear. Our previous studies have shown that the replications of genomic and antigenomic HDV RNA strands have different sensitivities to alpha-amanitin and are associated with different nuclear bodies, suggesting that these two strands are synthesized in different transcription machineries in the cells. In this study, we developed a unique quantitative reverse transcription-PCR (qRT-PCR) procedure for detection of various HDV RNA species from an RNA transfection system. Using this qRT-PCR procedure and a series of HDV mutants, we demonstrated that Arg-13 methylation, Lys-72 acetylation, and Ser-177 phosphorylation of small hepatitis delta antigen (S-HDAg) are important for HDV mRNA transcription. In addition, these three S-HDAg modifications are dispensable for antigenomic RNA synthesis but are required for genomic RNA synthesis. Furthermore, the three RNA species had different sensitivities to acetylation and deacetylation inhibitors, showing that the metabolic requirements for the synthesis of HDV antigenomic RNA are different from those for the synthesis of genomic RNA and mRNA. In sum, our data support the hypothesis that the cellular machinery involved in the synthesis of HDV antigenomic RNA is different from that of genomic RNA synthesis and mRNA transcription, even though the antigenomic RNA and the mRNA are made from the same RNA template. We propose that acetylation and deacetylation of HDAg may provide a molecular switch for the synthesis of the different HDV RNA species.
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19
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ERK1/2-mediated phosphorylation of small hepatitis delta antigen at serine 177 enhances hepatitis delta virus antigenomic RNA replication. J Virol 2008; 82:9345-58. [PMID: 18632853 DOI: 10.1128/jvi.00656-08] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The small hepatitis delta virus (HDV) antigen (SHDAg) plays an essential role in HDV RNA double-rolling-circle replication. Several posttranslational modifications (PTMs) of HDAgs, including phosphorylation, acetylation, and methylation, have been characterized. Among the PTMs, the serine 177 residue of SHDAg is a phosphorylation site, and its mutation preferentially abolishes HDV RNA replication from antigenomic RNA to genomic RNA. Using coimmunoprecipitation analysis, the cellular kinases extracellular signal-related kinases 1 and 2 (ERK1/2) are found to be associated with the Flag-tagged SHDAg mutant (Ser-177 replaced with Cys-177). In an in vitro kinase assay, serine 177 of SHDAg was phosphorylated directly by either Flag-ERK1 or Flag-ERK2. Activation of endogenous ERK1/2 by a constitutively active MEK1 (hemagglutinin-AcMEK1) increased phosphorylation of SHDAg at Ser-177; this phosphorylation was confirmed by immunoblotting using an antibody against phosphorylated S177 and mass spectrometric analysis. Interestingly, we found an increase in the HDV replication from antigenomic RNA to genomic RNA but not in that from genomic RNA to antigenomic RNA. The Ser-177 residue was critical for SHDAg interaction with RNA polymerase II (RNAPII), the enzyme proposed to regulate antigenomic RNA replication. These results demonstrate the role of ERK1/2-mediated Ser-177 phosphorylation in modulating HDV antigenomic RNA replication, possibly through RNAPII regulation. The results may shed light on the mechanisms of HDV RNA replication.
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20
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Nucleolar targeting of hepatitis delta antigen abolishes its ability to initiate viral antigenomic RNA replication. J Virol 2007; 82:692-9. [PMID: 17989182 DOI: 10.1128/jvi.01155-07] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hepatitis delta virus (HDV) is a small RNA virus that contains one 1.7-kb single-stranded circular RNA of negative polarity. The HDV particle also contains two isoforms of hepatitis delta antigen (HDAg), small (SHDAg) and large HDAg. SHDAg is required for the replication of HDV, which is presumably carried out by host RNA-dependent RNA polymerases. The localization and the HDAg and host RNA polymerase responsible for HDV replication remain important issues to be addressed. In this study, using recombinant SHDAg fused with a heterologous nucleolar localization sequence (NoLS) to confine its subcellular localization in nucleoli, we aimed to study the effect of SHDAg subcellular localization on HDV RNA replication. The initiation of genomic RNA synthesis from antigenomic template was hardly detectable when SHDAg was fused with the NoLS motif and localized mainly in nucleoli. In contrast, the initiation of antigenomic RNA synthesis was not affected. Drug treatment to release a SHDAg-NoLS mutant from nucleoli could partially restore the replication of HDV genomic RNA from antigenomic RNA. This also recovered the cointeraction between SHDAg and RNA polymerase II. These data strongly suggest that nuclear polymerase (RNA polymerase II) is involved in the synthesis of genomic RNA and that the synthesis of antigenomic RNA can occur in nucleoli. Our results support the idea that the replication of HDV genomic RNA or antigenomic RNA is likely to be carried out by different machineries in different subcellular localizations.
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21
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Abstract
HDV replicates its circular RNA genome using a double rolling-circle mechanism and transcribes a hepatitis delta antigen-encodeing mRNA from the same RNA template during its life cycle. Both processes are carried out by RNA-dependent RNA synthesis despite the fact that HDV does not encode an RNA-dependent RNA polymerase (RdRP). Cellular RNA polymerase II has long been implicated in these processes. Recent findings, however, have shown that the syntheses of genomic and antigenomic RNA strands have different metabolic requirements, including sensitives to alpha-amanitin and the site of synthesis. Evidence is summarized here for the involvement of other cellular polymerases, probably pol I, in the synthesis of antigenomic RNA strand. The ability of mammalian cells to replicate HDV RNA implies that RNA-dependent RNA synthesis was preserved throughout evolution.
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Affiliation(s)
- T B Macnaughton
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles 90033, USA
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22
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Huang WH, Chen CW, Wu HL, Chen PJ. Post-translational modification of delta antigen of hepatitis D virus. Curr Top Microbiol Immunol 2006; 307:91-112. [PMID: 16903222 DOI: 10.1007/3-540-29802-9_5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The hepatitis delta virus (HDV) genome has only one open reading frame, which encodes the viral small delta antigen. After RNA editing, the same open reading frame is extended 19 amino acids at the carboxyl terminus and encodes the large delta antigen. These two viral proteins escort the HDV genome through different cellular compartments for the complicated phases of replication, transcription and, eventually, the formation of progeny virions. To orchestrate these events, the delta antigens have to take distinct cues to traffic to the right compartments and make correct molecular contacts. In eukaryotes, post-translational modification (PTM) is a major mechanism of dictating the multiple functions of a single protein. Multiple PTMs, including phosphorylation, isoprenylation, acetylation, and methylation, have been identified on hepatitis delta antigens. In this chapter we review these PTMs and discuss their functions in regulating and coordinating the life cycle of HDV.
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Affiliation(s)
- W H Huang
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, and Hepatitis Research Center, National Taiwan University Hospital, Taipei
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23
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Huang IC, Chien CY, Huang CR, Lo SJ. Induction of hepatitis D virus large antigen translocation to the cytoplasm by hepatitis B virus surface antigens correlates with endoplasmic reticulum stress and NF-kappaB activation. J Gen Virol 2006; 87:1715-1723. [PMID: 16690938 DOI: 10.1099/vir.0.81718-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
It is known that hepatitis D virus (HDV) requires hepatitis B virus (HBV) for supplying envelope proteins (HBsAgs) to produce mature virions, and the HDV large antigen (LDAg) is responsible for interacting with HBsAgs. However, the signal molecules involved in the cross-talk between HBsAgs and LDAg have never been reported. It has been previously demonstrated that the small form of HBsAg can facilitate the translocation of HDV large antigen green fluorescent protein (GFP) fusion protein (GFP-LD) from the nucleus to the cytoplasm. In this study, it was confirmed that the small form of HBsAg can facilitate both GFP-LD and authentic LDAg for nuclear export. It was also shown that the three forms of HBsAgs (large, middle and small) induced various rates (from 35.4 to 57.2%) of GFP-LD nuclear export. Since HBsAgs are localized inside the endoplasmic reticulum (ER), this suggests that ER stress possibly initiates the signal for inducing LDAg translocation. This supposition is supported by results that show that around 9% of cells appear with GFP-LD in the cytoplasm after treatment with the ER stress inducers, brefeldin A (BFA) and tunicamycin, in the absence of HBsAg. Western blot and immunofluorescence microscopy results further showed that the activation of NF-kappaB is linked to the ER stress that induces GFP-LD translocation. Combining this with results showing that tumour necrosis factor alpha (TNF-alpha) can also induce GFP-LD translocation, it was concluded that LDAg translocation correlates with ER stress and activation of NF-kappaB. Nevertheless, TNF-alpha-induced GFP-LD translocation was independent of new protein synthesis, suggesting that a post-translational event occurs to GFP-LD to allow translocation.
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Affiliation(s)
- I-Cheng Huang
- Department of Microbiology and Immunology, Chang Gung University, Tao-Yuan, Taiwan 333, Republic of China
| | - Chia-Ying Chien
- Department of Microbiology and Immunology, Chang Gung University, Tao-Yuan, Taiwan 333, Republic of China
| | - Chi-Ruei Huang
- Graduate Institute of Biomedical Sciences and Department of Life Science, Chang Gung University, Tao-Yuan, Taiwan 333, Republic of China
| | - Szecheng J Lo
- Graduate Institute of Biomedical Sciences and Department of Life Science, Chang Gung University, Tao-Yuan, Taiwan 333, Republic of China
- Department of Microbiology and Immunology, Chang Gung University, Tao-Yuan, Taiwan 333, Republic of China
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24
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Hsieh TH, Liu CJ, Chen DS, Chen PJ. Natural Course and Treatment of Hepatitis D Virus Infection. J Formos Med Assoc 2006; 105:869-81. [PMID: 17098688 DOI: 10.1016/s0929-6646(09)60172-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatitis D virus (HDV) is a subviral satellite with hepatitis B virus (HBV) as its natural helper virus. After entry into hepatocytes, it utilizes host cellular enzymes to replicate by a double-rolling-circle mechanism. HDV is most often transmitted by contact with contaminated blood and body fluid, similar to HBV infection. Approximately 5% of the global HBV carriers are coinfected with HDV, leading to a total of 10-15 million HDV carriers worldwide. HDV infection can occur concurrently with HBV infection (coinfection) or in a patient with established HBV infection (superinfection). The pathogenesis of HDV remains controversial. A decline in the prevalence of both acute and chronic hepatitis D (CHD) has been observed worldwide. At present, therapy for chronic HDV infection is by the use of interferon-alpha. Compared to chronic hepatitis B or C, CHD treatment requires a higher dosage and a longer duration of treatment, and post-treatment relapses are common. In order to prevent the progression of CHD and its related morbidity and mortality, more effective treatments are needed.
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Affiliation(s)
- Ting-Hui Hsieh
- Department of Medicine, Maimonides Medical Center, New York, USA
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25
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Lai MMC. RNA replication without RNA-dependent RNA polymerase: surprises from hepatitis delta virus. J Virol 2005; 79:7951-8. [PMID: 15956541 PMCID: PMC1143735 DOI: 10.1128/jvi.79.13.7951-7958.2005] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Michael M C Lai
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, 2011 Zonal Ave., HMR503C, Los Angeles, California 90033, USA.
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26
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O'Malley B, Lazinski DW. Roles of carboxyl-terminal and farnesylated residues in the functions of the large hepatitis delta antigen. J Virol 2005; 79:1142-53. [PMID: 15613342 PMCID: PMC538544 DOI: 10.1128/jvi.79.2.1142-1153.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The large hepatitis delta antigen (HDAg-L) mediates hepatitis delta virus (HDV) assembly and inhibits HDV RNA replication. Farnesylation of the cysteine residue within the HDAg-L carboxyl terminus is required for both functions. Here, HDAg-L proteins from different HDV genotypes and genotype chimeric proteins were analyzed for their ability to incorporate into virus-like particles (VLPs). Observed differences in efficiency of VLP incorporation could be attributed to genotype-specific differences within the HDAg-L carboxyl terminus. Using a novel assay to quantify the extent of HDAg-L farnesylation, we found that genotype 3 HDAg-L was inefficiently farnesylated when expressed in the absence of the small hepatitis delta antigen (HDAg-S). However, as the intracellular ratio of HDAg-S to HDAg-L was increased, so too was the extent of HDAg-L farnesylation for all three genotypes. Single point mutations within the carboxyl terminus of HDAg-L were screened, and three mutants that severely inhibited assembly without affecting farnesylation were identified. The observed assembly defects persisted under conditions where the mutants were known to have access to the site of VLP assembly. Therefore, the corresponding residues within the wild-type protein are likely required for direct interaction with viral envelope proteins. Finally, it was observed that when HDAg-S was artificially myristoylated, it could efficiently inhibit HDV RNA replication. Hence, a general association with membranes enables HDAg to inhibit replication. In contrast, although myristoylated HDAg-S was incorporated into VLPs far more efficiently than HDAg-S or nonfarnesylated HDAg-L, it was incorporated far less efficiently than wild-type HDAg-L; thus, farnesylation was required for efficient assembly.
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Affiliation(s)
- Brendan O'Malley
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
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Tan KP, Shih KN, Lo SJ. Ser-123 of the large antigen of hepatitis delta virus modulates its cellular localization to the nucleolus, SC-35 speckles or the cytoplasm. J Gen Virol 2004; 85:1685-1694. [PMID: 15166453 DOI: 10.1099/vir.0.19690-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis delta virus (HDV) is a defective virus and requires hepatitis B virus (HBV) to supply envelope proteins (HBsAg) for maturation and secretion. It is known that two proteins produced by HDV, the small (SDAg) and large (LDAg) antigens, are located in the nucleolus, speckles and the cytoplasm and are involved in genome replication and virion packaging. However, little is known about how they are targeted to the specific sites where they act. A green fluorescence protein fused to LDAg (GFP–LD) has been shown previously to translocate from the nucleolus to SC-35 speckles in the presence of the casein kinase II inhibitor dichlororibofuranosyl benzimidazole. In this study, we determined which amino acids of GFP–LD were responsible for the translocation from the nucleolus to SC-35 speckles and created three GFP–LD derivatives, GFP–LDS2A, GFP–LDS123A and GFP–LDS2/123A. Fluorescence microscopy studies showed that Ser-123 mutants had a high tendency to target SC-35 speckles in both transfected HeLa and HuH-7 cells and suggested that Ser-123, but not Ser-2, plays a role in modulating LDAg translocation to the nucleolus or to SC-35 speckles. This study also demonstrated that HBsAg plays a role in facilitating the transportation of LDAg from the nucleus to cytoplasm. Compared with GFP–LD and GFP–LDS2A, mutants of Ser-123 were less efficiently transported to the cytoplasm and resulted in a lower level of secretion. In contrast, little or no isoprenylation mutant was observed in the cytoplasm of HuH-7 cells expressing HbsAg, suggesting that the isoprenylation of LDAg plays a role in export from the nucleus. Thus, the current study demonstrated that both cis and trans elements modulate HDAg translocation to various subcellular sites.
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Affiliation(s)
- Keng-Poo Tan
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan 112
| | - Ko-Nien Shih
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan 112
| | - Szecheng J Lo
- Department of Life Science, School of Medicine, Chang Gung University, TaoYun, Taiwan 333
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan 112
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Mu JJ, Tsay YG, Juan LJ, Fu TF, Huang WH, Chen DS, Chen PJ. The small delta antigen of hepatitis delta virus is an acetylated protein and acetylation of lysine 72 may influence its cellular localization and viral RNA synthesis. Virology 2004; 319:60-70. [PMID: 14967488 DOI: 10.1016/j.virol.2003.10.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Revised: 10/22/2003] [Accepted: 10/23/2003] [Indexed: 12/12/2022]
Abstract
Hepatitis delta virus (HDV) is a single-stranded RNA virus that encodes two viral nucleocapsid proteins named small and large form hepatitis delta antigen (S-HDAg and L-HDAg). The S-HDAg is essential for viral RNA replication while the L-HDAg is required for viral assembly. In this study, we demonstrated that HDAg are acetylated proteins. Metabolic labeling with [(3)H]acetate revealed that both forms of HDAg could be acetylated in vivo. The histone acetyltransferase (HAT) domain of cellular acetyltransferase p300 could acetylate the full-length and the N-terminal 88 amino acids of S-HDAg in vitro. By mass spectrometric analysis of the modified protein, Lys-72 of S-HDAg was identified as one of the acetylation sites. Substitution of Lys-72 to Arg caused the mutant S-HDAg to redistribute from the nucleus to the cytoplasm. The mutant reduced viral RNA accumulation and resulted in the earlier appearance of L-HDAg. These results demonstrated that HDAg is an acetylated protein and mutation of HDAg at Lys-72 modulates HDAg subcellular localization and may participate in viral RNA nucleocytoplasmic shuttling and replication.
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Affiliation(s)
- Jung-Jung Mu
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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29
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Abstract
In a natural setting, hepatitis delta virus (HDV) is only found in patients that are also infected with hepatitis B virus (HBV). In hepatocytes infected with these two viruses, HDV RNA genomes are assembled using the envelope proteins of HBV. Since 1986, we have known that HDV has a small single-stranded RNA genome with a unique circular conformation that is replicated using a host RNA polymerase. These and other features make HDV and its replication unique, at least among agents that infect animals. This mini-review focuses on advances gained over the last 2-3 years, together with an evaluation of HDV questions that are either unsolved or not yet solved satisfactorily.
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Affiliation(s)
- John M Taylor
- Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, PA 19111-2497, USA.
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Choi SH, Park KJ, Hwang SB. Large hepatitis delta antigen is phosphorylated at multiple sites and phosphorylation is associated with protein conformational change. Intervirology 2003; 45:142-9. [PMID: 12403918 DOI: 10.1159/000065867] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Hepatitis delta antigen (HDAg) consists of two species, small HDAg (SHDAg) and large HDAg (LHDAg), which are identical in sequence with the exception that the large form contains an additional 19 amino acids at the C-terminus. Both HDAgs are nuclear phosphoproteins. However, LHDAg is hyperphosphorylated, i.e. it is at least 10 times more phosphorylated than SHDAg. To determine the phosphorylation site(s) of the LHDAg, we mutated all the conserved serine residues and expressed these mutant proteins using a recombinant baculovirus expression system. By labeling insect cells in vivo with (32)P-orthophosphate and immunoprecipitation, we showed that LHDAg is phosphorylated at multiple serine residues. Although LHDAg contains two additional serines at its 19-amino acid extension, mutations of these two amino acids did not affect the overall phosphorylation level. Most importantly, the phosphorylation level of middle domain-deleted LHDAg (M75del) was significantly higher than that of wild-type LHDAg. We conclude that phosphorylation of the LHDAg occurs at multiple sites and that hyperphosphorylation is associated with alteration of protein conformation.
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Affiliation(s)
- Soo-Ho Choi
- Ilsong Institute of Life Science, The Hallym Academy of Sciences, Hallym University, Anyang, Korea
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Chen CW, Tsay YG, Wu HL, Lee CH, Chen DS, Chen PJ. The double-stranded RNA-activated kinase, PKR, can phosphorylate hepatitis D virus small delta antigen at functional serine and threonine residues. J Biol Chem 2002; 277:33058-67. [PMID: 12060652 DOI: 10.1074/jbc.m200613200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis D virus (HDV) encodes two proteins, the 24-kDa small delta antigen (S-HDAg) and 27-kDa large delta antigen (L-HDAg) in its single open reading frame. Both of them had been identified as nuclear phosphoproteins. Moreover, the phosphorylated form of S-HDAg was shown to be important for HDV replication. However, the kinase responsible for S-HDAg phosphorylation remains unknown. Therefore, we employed an in-gel kinase assay to search candidate kinases and indeed identified a kinase with a molecular mass of about 68 kDa. Much evidence demonstrated this kinase to be the double-stranded RNA-activated kinase, PKR. The immunoprecipitated endogenous PKR was sufficient to catalyze S-HDAg phosphorylation, and the kinase activity disappeared in the PKR-depleted cell lysate. The S-HDAg and PKR could be co-immunoprecipitated together, and both of them co-located in the nucleolus. The LC/MS/MS analysis revealed that the serine 177, serine 180, and threonine 182 of S-HDAg were phosphorylated by PKR in vitro. This result was consistent with previous phosphoamino acid analysis indicating that serine and threonine were phosphorylation targets in S-HDAg. Furthermore, serine 177 was also shown to be the predominant phosphorylation site for S-HDAg purified the from cell line. In dominant negative PKR-transfected cells, the level of phosphorylated S-HDAg was suppressed, but replication of HDV was enhanced. Other than human immunodeficiency virus type 1 trans-activating protein (Tat), S-HDAg is another viral protein phosphorylated by PKR that may regulates HDV replication and viral response to interferon therapy.
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Affiliation(s)
- Chi-Wu Chen
- Graduate Institute of Microbiology and Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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Macnaughton TB, Lai MMC. Genomic but not antigenomic hepatitis delta virus RNA is preferentially exported from the nucleus immediately after synthesis and processing. J Virol 2002; 76:3928-35. [PMID: 11907232 PMCID: PMC136093 DOI: 10.1128/jvi.76.8.3928-3935.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis delta virus (HDV) contains a viroid-like circular RNA that replicates via a double rolling circle replication mechanism. It is generally assumed that HDV RNA is synthesized and remains exclusively in the nucleus until being exported to the cytoplasm for virion assembly. Using a [32P]orthophosphate metabolic labeling procedure to study HDV RNA replication (T. B. Macnaughton, S. T. Shi, L. E. Modahl, and M. M. C. Lai. J. Virol. 76:3920-3927, 2002), we unexpectedly found that a significant amount of newly synthesized HDV RNA was detected in the cytoplasm. Surprisingly, Northern blot analysis revealed that the genomic-sense HDV RNA is present almost equally in both the nucleus and cytoplasm, whereas antigenomic HDV RNA was mostly retained in the nucleus, suggesting the specific and highly selective export of genomic HDV RNA. Kinetic studies showed that genomic HDV RNA was exported soon after synthesis. However, only the monomer and, to a lesser extent, the dimer HDV RNAs were exported to the cytoplasm; very little higher-molecular-weight HDV RNA species were detected in the cytoplasm. These results suggest that the cleavage and processing of HDV RNA may facilitate RNA export. The export of genomic HDV RNA was resistant to leptomycin B, indicating that a cell region maintenance 1 (Crm1)-independent pathway was involved. The large form of hepatitis delta antigen (L-HDAg), which is responsible for virus packaging, was not required for RNA export, as a mutant HDV RNA genome unable to synthesize L-HDAg was still exported. The proportions of genomic HDV RNA in the nucleus and cytoplasm remained relatively constant throughout replication, indicating that export of genomic HDV RNA occurred continuously. In contrast, while antigenomic HDV RNA was predominantly in the nucleus, there was a proportionally large fraction of antigenomic HDV RNA in the cytoplasm at early time points of RNA replication. These findings uncover a previously unrecognized presence of HDV RNA in the cytoplasm, which may have implications for viral RNA synthesis and packaging.
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Affiliation(s)
- Thomas B Macnaughton
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033-1054, USA
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