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Liu K, Li L, Liu Y, Wang X, Liu J, Li J, Deng F, Zhang R, Zhou Y, Hu Z, Zhong W, Wang M, Guo C. Discovery of baloxavir sodium as a novel anti-CCHFV inhibitor: Biological evaluation of in vitro and in vivo. Antiviral Res 2024; 227:105890. [PMID: 38657838 DOI: 10.1016/j.antiviral.2024.105890] [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: 02/20/2024] [Revised: 04/05/2024] [Accepted: 04/18/2024] [Indexed: 04/26/2024]
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is a highly pathogenic bunyavirus with a fatality rate of up to 40%. Currently, there are no licensed antiviral drugs for the treatment of CCHF; thus, the World Health Organization (WHO) listed the disease as a priority. A unique viral transcription initiation mechanism called "cap-snatching" is shared by influenza viruses and bunyaviruses. Thus, we tested whether baloxavir (an FDA-approved anti-influenza drug that targets the "cap-snatching" mechanism) could inhibit CCHFV infection. In cell culture, baloxavir acid effectively inhibited CCHFV infection and targeted CCHFV RNA transcription/replication. However, it has weak oral bioavailability. Baloxavir marboxil (the oral prodrug of baloxavir) failed to protect mice against a lethal dose challenge of CCHFV. To solve this problem, baloxavir sodium was synthesized owing to its enhanced aqueous solubility and pharmacokinetic properties. It consistently and significantly improved survival rates and decreased tissue viral loads. This study identified baloxavir sodium as a novel scaffold structure and mechanism of anti-CCHF compound, providing a promising new strategy for clinical treatment of CCHF after further optimization.
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Affiliation(s)
- Kai Liu
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China; National Engineering Research Center for the Emergency Drug, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - Liushuai Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yajie Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Xi Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jia Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jiang Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Runze Zhang
- National Engineering Research Center for the Emergency Drug, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - Yiwu Zhou
- Department of Forensic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430010, China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Wu Zhong
- National Engineering Research Center for the Emergency Drug, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; Hubei Jiangxia Laboratory, Wuhan, 430200, China.
| | - Chun Guo
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.
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Williams HM, Thorkelsson S, Vogel D, Busch C, Milewski M, Cusack S, Grünewald K, Quemin EJ, Rosenthal M. Structural snapshots of phenuivirus cap-snatching and transcription. Nucleic Acids Res 2024; 52:6049-6065. [PMID: 38709882 PMCID: PMC11162785 DOI: 10.1093/nar/gkae330] [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: 12/18/2023] [Revised: 04/10/2024] [Accepted: 04/19/2024] [Indexed: 05/08/2024] Open
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a human pathogen that is now endemic to several East Asian countries. The viral large (L) protein catalyzes viral transcription by stealing host mRNA caps via a process known as cap-snatching. Here, we establish an in vitro cap-snatching assay and present three high-quality electron cryo-microscopy (cryo-EM) structures of the SFTSV L protein in biologically relevant, transcription-specific states. In a priming-state structure, we show capped RNA bound to the L protein cap-binding domain (CBD). The L protein conformation in this priming structure is significantly different from published replication-state structures, in particular the N- and C-terminal domains. The capped-RNA is positioned in a way that it can feed directly into the RNA-dependent RNA polymerase (RdRp) ready for elongation. We also captured the L protein in an early-elongation state following primer-incorporation demonstrating that this priming conformation is retained at least in the very early stages of primer extension. This structural data is complemented by in vitro biochemical and cell-based assays. Together, these insights further our mechanistic understanding of how SFTSV and other bunyaviruses incorporate stolen host mRNA fragments into their viral transcripts thereby allowing the virus to hijack host cell translation machinery.
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Affiliation(s)
- Harry M Williams
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
| | - Sigurdur R Thorkelsson
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Dominik Vogel
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Carola Busch
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Morlin Milewski
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | | | - Kay Grünewald
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Emmanuelle R J Quemin
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
- Department of Virology, Institute for Integrative Biology of the Cell (I2BC), Centre National de la Recherche Scientifique (CNRS) UMR9198, Gif-sur-Yvette, France
| | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Hamburg, Germany
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3
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Miglioli F, Joel S, Tegoni M, Neira-Pelén P, Günther S, Carcelli M, Fisicaro E, Brancale A, Fernández-García Y, Rogolino D. Inhibitory interactions of the 2,3-dihydro-6,7-dihydroxy-1H-isoindol-1-one scaffold with Bunyavirales cap-snatching endonucleases expose relevant drug design features. Eur J Med Chem 2024; 272:116467. [PMID: 38735150 DOI: 10.1016/j.ejmech.2024.116467] [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: 03/04/2024] [Revised: 04/19/2024] [Accepted: 04/28/2024] [Indexed: 05/14/2024]
Abstract
The World Health Organization (WHO) identifies several bunyaviruses as significant threats to global public health security. Developing effective therapies against these viruses is crucial to combat future outbreaks and mitigate their impact on patient outcomes. Here, we report the synthesis of some isoindol-1-one derivatives and explore their inhibitory properties over an indispensable metal-dependent cap-snatching endonuclease (Cap-ENDO) shared among evolutionary divergent bunyaviruses. The compounds suppressed RNA hydrolysis by Cap-ENDOs, with IC50 values predominantly in the lower μM range. Molecular docking studies revealed the interactions with metal ions to be essential for the 2,3-dihydro-6,7-dihydroxy-1H-isoindol-1-one scaffold activity. Calorimetric analysis uncovered Mn2+ ions to have the highest affinity for sites within the targets, irrespective of aminoacidic variations influencing metal cofactor preferences. Interestingly, spectrophotometric findings unveiled sole dinuclear species formation between the scaffold and Mn2+. Moreover, the complexation of two Mn2+ ions within the viral enzymes appears to be favourable, as indicated by the binding of compound 11 to TOSV Cap-ENDO (Kd = 28 ± 3 μM). Additionally, the tendency of compound 11 to stabilize His+ more than His- Cap-ENDOs suggests exploitable differences in their catalytic pockets relevant to improving specificity. Collectively, our results underscore the isoindolinone scaffold's potential as a strategic starting point for the design of pan-antibunyavirus drugs.
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Affiliation(s)
- Francesca Miglioli
- Department of Chemistry, Life Sciences, Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Shindhuja Joel
- Department of Virology, Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Matteo Tegoni
- Department of Chemistry, Life Sciences, Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Pedro Neira-Pelén
- Department of Virology, Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stephan Günther
- Department of Virology, Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Mauro Carcelli
- Department of Chemistry, Life Sciences, Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Emilia Fisicaro
- Department of Food and Drug, University of Parma, Viale delle Scienze 27/A, 43124, Parma, Italy
| | - Andrea Brancale
- Department of Organic Chemistry, University of Chemistry and Technology, 16628, Prague, Czech Republic
| | - Yaiza Fernández-García
- Department of Virology, Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany.
| | - Dominga Rogolino
- Department of Chemistry, Life Sciences, Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy.
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Mandova T, Saivish MV, Menezes GDL, Bezerra KS, Fulco UL, da Silva RA, Da Costa FB, Nogueira ML. Antiviral Activity and Molecular Dynamics Simulation of Hops Compounds against Oropouche Virus ( Peribunyaviridae). Pharmaceutics 2023; 15:2769. [PMID: 38140109 PMCID: PMC10747393 DOI: 10.3390/pharmaceutics15122769] [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: 09/20/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
The Oropouche virus (OROV) is a member of the family Peribunyaviridae (order Bunyavirales) and the cause of a dengue-like febrile illness transmitted mainly by biting midges and mosquitoes. In this study, we aimed to explore acylphloroglucinols and xanthohumol from hops (Humulus lupulus L.) as a promising alternative for antiviral therapies. The evaluation of the inhibitory potential of hops compounds on the viral cycle of OROV was performed through two complementary approaches. The first approach applies cell-based assay post-inoculation experiments to explore the inhibitory potential on the latest steps of the viral cycle, such as genome translation, replication, virion assembly, and virion release from the cells. The second part covers in silico methods evaluating the ability of those compounds to inhibit the activity of the endonuclease domain, which is essential for transcription, binding, and cleaving RNA. In conclusion, the beta acids showed strongest inhibitory potential in post-treatment assay (EC50 = 26.7 µg/mL). Xanthohumol had the highest affinity for OROV endonuclease followed by colupulone and cohumulone. This result contrasts with that observed for docking and MM/PBSA analysis, where cohumulone was found to have a higher affinity. Finally, among the three tested ligands, Lys92 and Arg33 exhibited the highest affinity with the protein.
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Affiliation(s)
- Tsvetelina Mandova
- AsterBioChem Research Team, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-020, SP, Brazil
- Gilson Purification, 22 rue Bourseul, 56890 Saint Avé, France
| | - Marielena Vogel Saivish
- Laboratórios de Pesquisas em Virologia, Departamento de Doenças Dermatológicas, Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto 15090-000, SP, Brazil; (M.V.S.)
- Brazilian Biosciences National Laboratory, Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas 13083-100, SP, Brazil
| | - Gabriela de Lima Menezes
- Bioinformatics Multidisciplinary Environment, Programa de Pós Graduação em Bioinformática, Universidade Federal do Rio Grande do Norte, Natal 59078-400, RN, Brazil; (G.d.L.M.); (U.L.F.)
| | - Katyanna Sales Bezerra
- Bioinformatics Multidisciplinary Environment, Programa de Pós Graduação em Bioinformática, Universidade Federal do Rio Grande do Norte, Natal 59078-400, RN, Brazil; (G.d.L.M.); (U.L.F.)
| | - Umberto Laino Fulco
- Bioinformatics Multidisciplinary Environment, Programa de Pós Graduação em Bioinformática, Universidade Federal do Rio Grande do Norte, Natal 59078-400, RN, Brazil; (G.d.L.M.); (U.L.F.)
| | | | - Fernando Batista Da Costa
- AsterBioChem Research Team, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-020, SP, Brazil
| | - Maurício Lacerda Nogueira
- Laboratórios de Pesquisas em Virologia, Departamento de Doenças Dermatológicas, Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto 15090-000, SP, Brazil; (M.V.S.)
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
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5
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Meier K, Thorkelsson SR, Durieux Trouilleton Q, Vogel D, Yu D, Kosinski J, Cusack S, Malet H, Grünewald K, Quemin ERJ, Rosenthal M. Structural and functional characterization of the Sin Nombre virus L protein. PLoS Pathog 2023; 19:e1011533. [PMID: 37549153 PMCID: PMC10406178 DOI: 10.1371/journal.ppat.1011533] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/04/2023] [Indexed: 08/09/2023] Open
Abstract
The Bunyavirales order is a large and diverse group of segmented negative-strand RNA viruses. Several virus families within this order contain important human pathogens, including Sin Nombre virus (SNV) of the Hantaviridae. Despite the high epidemic potential of bunyaviruses, specific medical countermeasures such as vaccines or antivirals are missing. The multifunctional ~250 kDa L protein of hantaviruses, amongst other functional domains, harbors the RNA-dependent RNA polymerase (RdRp) and an endonuclease and catalyzes transcription as well as replication of the viral RNA genome, making it a promising therapeutic target. The development of inhibitors targeting these key processes requires a profound understanding of the catalytic mechanisms. Here, we established expression and purification protocols of the full-length SNV L protein bearing the endonuclease mutation K124A. We applied different biochemical in vitro assays to provide an extensive characterization of the different enzymatic functions as well as the capacity of the hantavirus L protein to interact with the viral RNA. By using single-particle cryo-EM, we obtained a 3D model including the L protein core region containing the RdRp, in complex with the 5' promoter RNA. This first high-resolution model of a New World hantavirus L protein shows striking similarity to related bunyavirus L proteins. The interaction of the L protein with the 5' RNA observed in the structural model confirms our hypothesis of protein-RNA binding based on our biochemical data. Taken together, this study provides an excellent basis for future structural and functional studies on the hantavirus L protein and for the development of antiviral compounds.
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Affiliation(s)
- Kristina Meier
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Sigurdur R. Thorkelsson
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | | | - Dominik Vogel
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Dingquan Yu
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- European Molecular Biology Laboratory (EMBL), Hamburg, Germany
| | - Jan Kosinski
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- European Molecular Biology Laboratory (EMBL), Hamburg, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Stephen Cusack
- European Molecular Biology Laboratory (EMBL), Grenoble, France
| | - Hélène Malet
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
- Institut Universitaire de France (IUF), Paris, France
| | - Kay Grünewald
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
- University of Hamburg, Department of Chemistry, Hamburg, Germany
| | - Emmanuelle R. J. Quemin
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Hamburg, Germany
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Williams HM, Thorkelsson SR, Vogel D, Milewski M, Busch C, Cusack S, Grünewald K, Quemin EJ, Rosenthal M. Structural insights into viral genome replication by the severe fever with thrombocytopenia syndrome virus L protein. Nucleic Acids Res 2023; 51:1424-1442. [PMID: 36651274 PMCID: PMC9943659 DOI: 10.1093/nar/gkac1249] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/29/2022] [Accepted: 12/14/2022] [Indexed: 01/19/2023] Open
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a phenuivirus that has rapidly become endemic in several East Asian countries. The large (L) protein of SFTSV, which includes the RNA-dependent RNA polymerase (RdRp), is responsible for catalysing viral genome replication and transcription. Here, we present 5 cryo-electron microscopy (cryo-EM) structures of the L protein in several states of the genome replication process, from pre-initiation to late-stage elongation, at a resolution of up to 2.6 Å. We identify how the L protein binds the 5' viral RNA in a hook-like conformation and show how the distal 5' and 3' RNA ends form a duplex positioning the 3' RNA terminus in the RdRp active site ready for initiation. We also observe the L protein stalled in the early and late stages of elongation with the RdRp core accommodating a 10-bp product-template duplex. This duplex ultimately splits with the template binding to a designated 3' secondary binding site. The structural data and observations are complemented by in vitro biochemical and cell-based mini-replicon assays. Altogether, our data provide novel key insights into the mechanism of viral genome replication by the SFTSV L protein and will aid drug development against segmented negative-strand RNA viruses.
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Affiliation(s)
| | | | - Dominik Vogel
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Morlin Milewski
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Carola Busch
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | | | - Kay Grünewald
- Centre for Structural Systems Biology, Leibniz Institute of Virology, Hamburg, Germany,University of Hamburg, Hamburg, Germany
| | - Emmanuelle R J Quemin
- Centre for Structural Systems Biology, Leibniz Institute of Virology, Hamburg, Germany
| | - Maria Rosenthal
- To whom correspondence should be addressed. Tel: +49 40 285380 930;
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Malet H, Williams HM, Cusack S, Rosenthal M. The mechanism of genome replication and transcription in bunyaviruses. PLoS Pathog 2023; 19:e1011060. [PMID: 36634042 PMCID: PMC9836281 DOI: 10.1371/journal.ppat.1011060] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Bunyaviruses are negative sense, single-strand RNA viruses that infect a wide range of vertebrate, invertebrate and plant hosts. WHO lists three bunyavirus diseases as priority diseases requiring urgent development of medical countermeasures highlighting their high epidemic potential. While the viral large (L) protein containing the RNA-dependent RNA polymerase is a key enzyme in the viral replication cycle and therefore a suitable drug target, our knowledge on the structure and activities of this multifunctional protein has, until recently, been very limited. However, in the last few years, facilitated by the technical advances in the field of cryogenic electron microscopy, many structures of bunyavirus L proteins have been solved. These structures significantly enhance our mechanistic understanding of bunyavirus genome replication and transcription processes and highlight differences and commonalities between the L proteins of different bunyavirus families. Here, we provide a review of our current understanding of genome replication and transcription in bunyaviruses with a focus on the viral L protein. Further, we compare within bunyaviruses and with the related influenza virus polymerase complex and highlight open questions.
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Affiliation(s)
- Hélène Malet
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
- Institut Universitaire de France (IUF), Paris, France
| | - Harry M. Williams
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
| | | | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Hamburg, Germany
- * E-mail:
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Structural and Biochemical Basis for Development of Diketo Acid Inhibitors Targeting the Cap-Snatching Endonuclease of the Ebinur Lake Virus (Order: Bunyavirales). J Virol 2022; 96:e0217321. [PMID: 35266805 DOI: 10.1128/jvi.02173-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Bunyavirales contain many important human pathogens that lack an antiviral therapy. The cap-snatching endonuclease (EN) of segmented negative-strand RNA viruses is an attractive target for broad-spectrum antivirals due to its essential role in initiating viral transcription. L-742,001, a previously reported diketo acid inhibitor against influenza virus EN, demonstrated potent EN inhibition and antiviral activity on various bunyaviruses. However, the precise inhibitory mechanism of the compound is still poorly understood. We recently characterized a highly active EN from Ebinur Lake virus (EBIV), a newly identified member of the Orthobunyavirus genus, and obtained its high-resolution structures, paving the way for structure-guided inhibitor development. Here, nine L-742,001 derivatives were designed and synthesized de novo, and their structure-activity relationship with EBIV EN was studied. In vitro biochemical data showed that the compounds inhibited the EBIV EN activity with different levels and could be divided into three categories. Five representative compounds were selected for further cell-based antiviral assay, and the results largely agreed with those of the EN assays. Furthermore, the precise binding modes of L-742,001 and its derivatives in EN were revealed by determining the high-resolution crystal structures of EN-inhibitor complexes, which suggested that the p-chlorobenzene is essential for the inhibitory activity and the flexible phenyl has the greatest exploration potential. This study provides an important basis for the structure-based design and optimization of inhibitors targeting EN of segmented negative-strand RNA viruses. IMPORTANCE The Bunyavirales contain many important human pathogens such as Crimean-Congo hemorrhagic fever virus and Lassa virus that pose serious threats to public health; however, currently there are no specific antiviral drugs against these viruses. The diketo acid inhibitor L-742,001 is a potential drug as it inactivates the cap-snatching endonuclease (EN) encoded by bunyaviruses. Here, we designed and synthesized nine L-742,001 derivatives and assessed the structure-activity relationship using EN of the newly identified Ebinur Lake virus (EBIV) as a research model. Our results revealed that the p-chlorobenzene of this broad-spectrum EN inhibitor is crucial for the inhibitory activity and the flexible phenyl "arm" has the best potential for further optimization. As cap-snatching ENs are present not only in bunyaviruses but also in influenza viruses, our data provide important guidelines for the development of novel and more potent diketo acid-based antiviral drugs against those viruses.
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Insights into two-metal-ion catalytic mechanism of cap-snatching endonuclease of Ebinur Lake virus in Bunyavirales. J Virol 2022; 96:e0208521. [PMID: 35044209 DOI: 10.1128/jvi.02085-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cap-snatching endonuclease (EN) of segmented negative-strand RNA viruses (sNSVs) produces short capped primers for viral transcription by cleaving the host mRNAs. EN requires divalent metals as cofactors for nucleic acid substrates cleavage, however, the detailed mechanism of metal ion-dependent catalysis of ENs remains obscure. In this work, we reported the EN crystal structure of the Ebinur Lake virus (EBIV), an emerging mosquito-borne orthobunyavirus, and investigated its enzymatic properties and metal ion-based catalytic mechanism. In vitro biochemical data showed that EBIV EN is a specific RNA nuclease and prefers to cleave unstructured uridine-rich ssRNA. Structural comparison indicated that the overall structural architecture of EBIV EN is similar to that of other sNSV ENs, while the detailed active site configuration including the binding state of metal ions and the conformation of the LA/LB loop pair is different. Base on sequence conservation analysis, nine active site mutants were constructed, and seven crystal structures of them were determined. Mutations of active site residues associated with the two metal ions (Mn1 and Mn2) coordination abolished EN activity. Crystallographic analyses further revealed that none of these mutants bound two metal ions simultaneously in the active site. Importantly, we found that the perturbation of Mn1-coordination (metal site 1), resulted in the enhancement or elimination of Mn2-coordination (metal site 2). Taken together, our data provide structural evidence to support the two-metal-ion catalytic mechanism of EBIV EN and the correlation of metal binding at the two binding sites, which may be commonly shared by bunyaviruses or other sNSVs. IMPORTANCE The viral endonucleases (ENs) encoded by bunyaviruses and orthomyxoviruses play an essential role in initiating transcription by "snatching" capped primers from the host mRNAs. These ENs are metal-ion-dependent nucleases, however, the details of their catalytic mechanism remain elusive. Here, we reported high-resolution crystal structures of the wild-type and mutant ENs of a novel bunyavirus, the Ebinur Lake virus (EBIV), and revealed the structure and function relationship of EN. The EBIV EN exhibited differences in the details of active site structure compared to its homologues. Our data provided structural evidence to support a two-metal-ion catalytic mechanism of EBIV EN, and found the correlation of metal binding at both binding sites, which might reflect the dynamic structural properties that correlate to EN catalytic function. Taken together, our results revealed the structural characteristics of EBIV EN and made important implications for understanding the catalytic mechanism of cap-snatching ENs.
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Lin Y, Gross ML. Mass Spectrometry-Based Structural Proteomics for Metal Ion/Protein Binding Studies. Biomolecules 2022; 12:135. [PMID: 35053283 PMCID: PMC8773722 DOI: 10.3390/biom12010135] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/13/2022] [Accepted: 01/13/2022] [Indexed: 01/01/2023] Open
Abstract
Metal ions are critical for the biological and physiological functions of many proteins. Mass spectrometry (MS)-based structural proteomics is an ever-growing field that has been adopted to study protein and metal ion interactions. Native MS offers information on metal binding and its stoichiometry. Footprinting approaches coupled with MS, including hydrogen/deuterium exchange (HDX), "fast photochemical oxidation of proteins" (FPOP) and targeted amino-acid labeling, identify binding sites and regions undergoing conformational changes. MS-based titration methods, including "protein-ligand interactions by mass spectrometry, titration and HD exchange" (PLIMSTEX) and "ligand titration, fast photochemical oxidation of proteins and mass spectrometry" (LITPOMS), afford binding stoichiometry, binding affinity, and binding order. These MS-based structural proteomics approaches, their applications to answer questions regarding metal ion protein interactions, their limitations, and recent and potential improvements are discussed here. This review serves as a demonstration of the capabilities of these tools and as an introduction to wider applications to solve other questions.
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Affiliation(s)
- Yanchun Lin
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
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11
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Pyle JD, Whelan SPJ, Bloyet LM. Structure and function of negative-strand RNA virus polymerase complexes. Enzymes 2021; 50:21-78. [PMID: 34861938 DOI: 10.1016/bs.enz.2021.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Viruses with negative-strand RNA genomes (NSVs) include many highly pathogenic and economically devastating disease-causing agents of humans, livestock, and plants-highlighted by recent Ebola and measles virus epidemics, and continuously circulating influenza virus. Because of their protein-coding orientation, NSVs face unique challenges for efficient gene expression and genome replication. To overcome these barriers, NSVs deliver a large and multifunctional RNA-dependent RNA polymerase into infected host cells. NSV-encoded polymerases contain all the enzymatic activities required for transcription and replication of their genome-including RNA synthesis and mRNA capping. Here, we review the structures and functions of NSV polymerases with a focus on key domains responsible for viral replication and gene expression. We highlight shared and unique features among polymerases of NSVs from the Mononegavirales, Bunyavirales, and Articulavirales orders.
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Affiliation(s)
- Jesse D Pyle
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States; Ph.D. Program in Virology, Harvard Medical School, Boston, MA, United States
| | - Sean P J Whelan
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States.
| | - Louis-Marie Bloyet
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States.
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12
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Meier K, Thorkelsson SR, Quemin ERJ, Rosenthal M. Hantavirus Replication Cycle-An Updated Structural Virology Perspective. Viruses 2021; 13:1561. [PMID: 34452426 PMCID: PMC8402763 DOI: 10.3390/v13081561] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 11/17/2022] Open
Abstract
Hantaviruses infect a wide range of hosts including insectivores and rodents and can also cause zoonotic infections in humans, which can lead to severe disease with possible fatal outcomes. Hantavirus outbreaks are usually linked to the population dynamics of the host animals and their habitats being in close proximity to humans, which is becoming increasingly important in a globalized world. Currently there is neither an approved vaccine nor a specific and effective antiviral treatment available for use in humans. Hantaviruses belong to the order Bunyavirales with a tri-segmented negative-sense RNA genome. They encode only five viral proteins and replicate and transcribe their genome in the cytoplasm of infected cells. However, many details of the viral amplification cycle are still unknown. In recent years, structural biology methods such as cryo-electron tomography, cryo-electron microscopy, and crystallography have contributed essentially to our understanding of virus entry by membrane fusion as well as genome encapsidation by the nucleoprotein. In this review, we provide an update on the hantavirus replication cycle with a special focus on structural virology aspects.
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Affiliation(s)
- Kristina Meier
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany;
| | - Sigurdur R. Thorkelsson
- Centre for Structural Systems Biology, Leibniz Institute for Experimental Virology, University of Hamburg, 22607 Hamburg, Germany;
| | - Emmanuelle R. J. Quemin
- Centre for Structural Systems Biology, Leibniz Institute for Experimental Virology, University of Hamburg, 22607 Hamburg, Germany;
| | - Maria Rosenthal
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany;
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, 22525 Hamburg, Germany
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13
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Fearns R. Negative‐strand RNA Viruses. Virology 2021. [DOI: 10.1002/9781119818526.ch3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Fernández-García Y, Horst ST, Bassetto M, Brancale A, Neyts J, Rogolino D, Sechi M, Carcelli M, Günther S, Rocha-Pereira J. Diketo acids inhibit the cap-snatching endonuclease of several Bunyavirales. Antiviral Res 2020; 183:104947. [PMID: 32980445 DOI: 10.1016/j.antiviral.2020.104947] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/26/2020] [Accepted: 08/29/2020] [Indexed: 12/12/2022]
Abstract
Several fatal bunyavirus infections lack specific treatment. Here, we show that diketo acids engage a panel of bunyavirus cap-snatching endonucleases, inhibit their catalytic activity and reduce viral replication of a taxonomic representative in vitro. Specifically, the non-salt form of L-742,001 and its derivatives exhibited EC50 values between 5.6 and 6.9 μM against a recombinant BUNV-mCherry virus. Structural analysis and molecular docking simulations identified traits of both the class of chemical entities and the viral target that could help the design of novel, more potent molecules for the development of pan-bunyavirus antivirals.
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Affiliation(s)
- Yaiza Fernández-García
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.
| | | | - Marcella Bassetto
- Department of Chemistry, College of Science, Swansea University, United Kingdom
| | - Andrea Brancale
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, United Kingdom
| | - Johan Neyts
- KU Leuven, Rega Institute for Medical Research, Belgium
| | - Dominga Rogolino
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area Delle Scienze, Parma, Italy
| | - Mario Sechi
- Department of Chemistry and Pharmacy, Laboratory of Drug Design and Nanomedicine, University of Sassari, Italy
| | - Mauro Carcelli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area Delle Scienze, Parma, Italy
| | - Stephan Günther
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
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15
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Jones R, Lessoued S, Meier K, Devignot S, Barata-García S, Mate M, Bragagnolo G, Weber F, Rosenthal M, Reguera J. Structure and function of the Toscana virus cap-snatching endonuclease. Nucleic Acids Res 2020; 47:10914-10930. [PMID: 31584100 PMCID: PMC6847833 DOI: 10.1093/nar/gkz838] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 09/14/2019] [Accepted: 10/01/2019] [Indexed: 12/03/2022] Open
Abstract
Toscana virus (TOSV) is an arthropod-borne human pathogen responsible for seasonal outbreaks of fever and meningoencephalitis in the Mediterranean basin. TOSV is a segmented negative-strand RNA virus (sNSV) that belongs to the genus phlebovirus (family Phenuiviridae, order Bunyavirales), encompassing other important human pathogens such as Rift Valley fever virus (RVFV). Here, we carried out a structural and functional characterization of the TOSV cap-snatching endonuclease, an N terminal domain of the viral polymerase (L protein) that provides capped 3′OH primers for transcription. We report TOSV endonuclease crystal structures in the apo form, in complex with a di-ketoacid inhibitor (DPBA) and in an intermediate state of inhibitor release, showing details on substrate binding and active site dynamics. The structure reveals substantial folding rearrangements absent in previously reported cap-snatching endonucleases. These include the relocation of the N terminus and the appearance of new structural motifs important for transcription and replication. The enzyme shows high activity rates comparable to other His+ cap-snatching endonucleases. Moreover, the activity is dependent on conserved residues involved in metal ion and substrate binding. Altogether, these results bring new light on the structure and function of cap-snatching endonucleases and pave the way for the development of specific and broad-spectrum antivirals.
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Affiliation(s)
- Rhian Jones
- Aix-Marseille Université, CNRS, AFMB UMR 7257, 13288 Marseille, France
| | - Sana Lessoued
- Aix-Marseille Université, CNRS, AFMB UMR 7257, 13288 Marseille, France
| | - Kristina Meier
- Bernhard Nocht Institute for Tropical Medicine, Department of Virology, D-20359 Hamburg, Germany
| | - Stéphanie Devignot
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, D-35392 Giessen, Germany
| | | | - Maria Mate
- Aix-Marseille Université, CNRS, AFMB UMR 7257, 13288 Marseille, France
| | | | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, D-35392 Giessen, Germany
| | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine, Department of Virology, D-20359 Hamburg, Germany
| | - Juan Reguera
- Aix-Marseille Université, CNRS, AFMB UMR 7257, 13288 Marseille, France.,INSERM, AFMB UMR7257,13288 Marseille, France
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16
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Meeting report: Eleventh International Conference on Hantaviruses. Antiviral Res 2020; 176:104733. [PMID: 32068071 DOI: 10.1016/j.antiviral.2020.104733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 02/01/2020] [Indexed: 12/24/2022]
Abstract
The 2019 11th International Conference on Hantaviruses (ICH 2019) was organized by the International Society for Hantaviruses (ISH), and held on September 1-4, 2019, at the Irish College, in Leuven, Belgium. These ICHs have been held every three years since 1989. ICH 2019 was attended by 158 participants from 33 countries. The current report summarizes research presented on all aspects of hantavirology: ecology; pathogenesis and immune responses; virus phylogeny, replication and morphogenesis; epidemiology; vaccines, therapeutics and prevention; and clinical aspects and diagnosis.
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17
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Olschewski S, Cusack S, Rosenthal M. The Cap-Snatching Mechanism of Bunyaviruses. Trends Microbiol 2020; 28:293-303. [PMID: 31948728 DOI: 10.1016/j.tim.2019.12.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 12/09/2019] [Indexed: 11/25/2022]
Abstract
In common with all segmented negative-sense RNA viruses, bunyavirus transcripts contain heterologous sequences at their 5' termini originating from capped host cell RNAs. These heterologous sequences are acquired by a so-called cap-snatching mechanism. Whereas for nuclear replicating influenza virus the source of capped primers as well as the cap-binding and endonuclease activities of the viral polymerase needed for cap snatching have been functionally and structurally well characterized, our knowledge on the expected counterparts of cytoplasmic replicating bunyaviruses is still limited and controversial. This review focuses on the cap-snatching mechanism of bunyaviruses in the light of recent structural and functional data.
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Affiliation(s)
- Silke Olschewski
- Bernhard Nocht Institute for Tropical Medicine, Department of Virology, Hamburg, Germany
| | | | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine, Department of Virology, Hamburg, Germany.
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18
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Wang W, Shin WJ, Zhang B, Choi Y, Yoo JS, Zimmerman MI, Frederick TE, Bowman GR, Gross ML, Leung DW, Jung JU, Amarasinghe GK. The Cap-Snatching SFTSV Endonuclease Domain Is an Antiviral Target. Cell Rep 2020; 30:153-163.e5. [PMID: 31914382 PMCID: PMC7214099 DOI: 10.1016/j.celrep.2019.12.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 10/31/2019] [Accepted: 12/06/2019] [Indexed: 01/08/2023] Open
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne virus with 12%-30% case mortality rates and is related to the Heartland virus (HRTV) identified in the United States. Together, SFTSV and HRTV are emerging segmented, negative-sense RNA viral (sNSV) pathogens with potential global health impact. Here, we characterize the amino-terminal cap-snatching endonuclease domain of SFTSV polymerase (L) and solve a 2.4-Å X-ray crystal structure. While the overall structure is similar to those of other cap-snatching sNSV endonucleases, differences near the C terminus of the SFTSV endonuclease suggest divergence in regulation. Influenza virus endonuclease inhibitors, including the US Food and Drug Administration (FDA) approved Baloxavir (BXA), inhibit the endonuclease activity in in vitro enzymatic assays and in cell-based studies. BXA displays potent activity with a half maximal inhibitory concentration (IC50) of ∼100 nM in enzyme inhibition and an EC50 value of ∼250 nM against SFTSV and HRTV in plaque assays. Together, our data support sNSV endonucleases as an antiviral target.
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Affiliation(s)
- Wenjie Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Woo-Jin Shin
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Bojie Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Younho Choi
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Ji-Seung Yoo
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Maxwell I Zimmerman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Thomas E Frederick
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Gregory R Bowman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Daisy W Leung
- Division of Infectious Diseases, John T. Milliken Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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19
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Ye C, Wang D, Liu H, Ma H, Dong Y, Yao M, Wang Y, Zhang H, Zhang L, Cheng L, Xu Z, Lei Y, Zhang F, Ye W. An Improved Enzyme-Linked Focus Formation Assay Revealed Baloxavir Acid as a Potential Antiviral Therapeutic Against Hantavirus Infection. Front Pharmacol 2019; 10:1203. [PMID: 31680975 PMCID: PMC6807675 DOI: 10.3389/fphar.2019.01203] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/17/2019] [Indexed: 12/18/2022] Open
Abstract
Hantaviruses, etiologic pathogens responsible for two severe human diseases, exist in areas ranging from Eurasia to America and remain global public health concerns. Conventionally, plaque formation assays have been used for hantavirus titering. However, hantaviruses replicate slowly within cells and produce minimal cytopathic effects, making this technique difficult to master. The improved enzyme-linked immunosorbent assay-based antigen detection method is easier to perform but is still time consuming. Here, we established an enzyme-linked focus formation assay (FFA) for Hantaan virus titering that is twice as fast as traditional assays. Moreover, using this method, we evaluated the effects of favipiravir (T-705) and another influenza virus drug, baloxavir acid (BXA), on hantavirus replication. We found that the endonuclease inhibitor BXA exerted similar anti-hantavirus effects as T-705. Overall, we developed a time-saving method for hantavirus titering and suggest BXA as a potential treatment choice for hantavirus-exposed individuals.
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Affiliation(s)
- Chuantao Ye
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China.,Department of Infectious Diseases, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Dan Wang
- School of Pharmaceutical Science, Shanxi Medical University, Taiyuan, China
| | - He Liu
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Hongwei Ma
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Yangchao Dong
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Min Yao
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Yuan Wang
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Hui Zhang
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Liang Zhang
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Linfeng Cheng
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Zhikai Xu
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Yingfeng Lei
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Fanglin Zhang
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Wei Ye
- Department of Microbiology, School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
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20
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Jérôme H, Rudolf M, Lelke M, Pahlmann M, Busch C, Bockholt S, Wurr S, Günther S, Rosenthal M, Kerber R. Rift Valley fever virus minigenome system for investigating the role of L protein residues in viral transcription and replication. J Gen Virol 2019; 100:1093-1098. [DOI: 10.1099/jgv.0.001281] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- Hanna Jérôme
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Martin Rudolf
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Michaela Lelke
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Meike Pahlmann
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Carola Busch
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Sabrina Bockholt
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stephanie Wurr
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stephan Günther
- 2 German Center for Infection Research (DZIF), Partner site Hamburg – Lübeck – Borstel – Riems, Hamburg, Germany
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Maria Rosenthal
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Romy Kerber
- 1 Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- 2 German Center for Infection Research (DZIF), Partner site Hamburg – Lübeck – Borstel – Riems, Hamburg, Germany
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21
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Gogrefe N, Reindl S, Günther S, Rosenthal M. Structure of a functional cap-binding domain in Rift Valley fever virus L protein. PLoS Pathog 2019; 15:e1007829. [PMID: 31136637 PMCID: PMC6555543 DOI: 10.1371/journal.ppat.1007829] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/07/2019] [Accepted: 05/08/2019] [Indexed: 11/25/2022] Open
Abstract
Rift Valley fever virus (RVFV) belongs to the family of Phenuiviridae within the order of Bunyavirales. The virus may cause fatal disease both in livestock and humans, and therefore, is of great economical and public health relevance. In analogy to the influenza virus polymerase complex, the bunyavirus L protein is assumed to bind to and cleave off cap structures of cellular mRNAs to prime viral transcription. However, even though the presence of an endonuclease in the N-terminal domain of the L protein has been demonstrated for several bunyaviruses, there is no evidence for a cap-binding site within the L protein. We solved the structure of a C-terminal 117 amino acid-long domain of the RVFV L protein by X-ray crystallography. The overall fold of the domain shows high similarity to influenza virus PB2 cap-binding domain and the putative non-functional cap-binding domain of reptarenaviruses. Upon co-crystallization with m7GTP, we detected the cap-analogue bound between two aromatic side chains as it has been described for other cap-binding proteins. We observed weak but specific interaction with m7GTP rather than GTP in vitro using isothermal titration calorimetry. The importance of m7GTP-binding residues for viral transcription was validated using a RVFV minigenome system. In summary, we provide structural and functional evidence for a cap-binding site located within the L protein of a virus from the Bunyavirales order. Rift Valley fever virus (RVFV) is endemic to sub-Saharan Africa and the Arabian Peninsula and leads to abortions in and death of ruminants. The virus can also be transmitted to humans causing febrile illness up to hemorrhagic fever with the possibility of fatal outcome. As there is currently no human vaccine or specific treatment available and because of the high epidemic potential, WHO has listed RVFV on its R&D Blueprint for urgent development of medical countermeasures. In order to amplify, the virus needs to transcribe and replicate the viral genome inside the cell cytoplasm. For transcription, the virus uses a process called cap-snatching, which is essentially depending on two functions presumed to reside within the large viral L protein: the ability to bind cap-structures and the activity of cleaving them off from cellular mRNA. Both functions could serve as specific targets for antiviral drug design. We identified and solved the structure of the cap-binding domain of RVFV and provide the first evidence for the presence of a functional cap-binding site in the L protein of bunyaviruses. Comparison with cap-binding proteins of related viruses revealed similarities and important differences critical for the development of potential broad-spectrum antivirals.
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Affiliation(s)
- Nadja Gogrefe
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Sophia Reindl
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stephan Günther
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Maria Rosenthal
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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22
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Vogel D, Rosenthal M, Gogrefe N, Reindl S, Günther S. Biochemical characterization of the Lassa virus L protein. J Biol Chem 2019; 294:8088-8100. [PMID: 30926610 PMCID: PMC6527160 DOI: 10.1074/jbc.ra118.006973] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/19/2019] [Indexed: 12/25/2022] Open
Abstract
The L protein of arena- and bunyaviruses is structurally and functionally related to the orthomyxovirus polymerase complex. It plays a central role in the viral life cycle, as it replicates the virus genome and generates viral mRNA via a cap-snatching mechanism. Here, we aimed to biochemically characterize the L protein of Lassa virus, a human-pathogenic arenavirus endemic in West Africa. Full-length 250-kDa L protein was expressed using a baculovirus expression system. A low-resolution structure calculated from small-angle X-ray scattering data revealed a conformation similar to that in the crystal structure of the orthomyxovirus polymerase complex. Although the L protein did not exhibit cap-snatching endonuclease activity, it synthesized RNA in vitro. RNA polymerization required manganese rather than magnesium ions, was independent of nucleotide primers, and was inhibited by viral Z protein. Maximum activity was mediated by double-stranded promoter sequences with a minimum length of 17 nucleotides, containing a nontemplated 5′-G overhang, as in the natural genome context, as well as the naturally occurring base mismatches between the complementary promoter strands. Experiments with various short primers revealed the presence of two replication initiation sites at the template strand and evidence for primer translocation as proposed by the prime-and-realign hypothesis. Overall, our findings provide the foundation for a detailed understanding of the mechanistic differences and communalities in the polymerase proteins of segmented negative-strand RNA viruses and for the search for antiviral compounds targeting the RNA polymerase of Lassa virus.
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Affiliation(s)
- Dominik Vogel
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, Hamburg 20359, Germany
| | - Maria Rosenthal
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, Hamburg 20359, Germany
| | - Nadja Gogrefe
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, Hamburg 20359, Germany
| | - Sophia Reindl
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, Hamburg 20359, Germany.
| | - Stephan Günther
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, Hamburg 20359, Germany; German Center for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel-Riems, Hamburg 20359, Germany.
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23
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Hantavirus RdRp Requires a Host Cell Factor for Cap Snatching. J Virol 2019; 93:JVI.02088-18. [PMID: 30541836 DOI: 10.1128/jvi.02088-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 11/20/2022] Open
Abstract
The hantavirus RNA-dependent RNA polymerase (RdRp) snatches 5' capped mRNA fragments from the host cell transcripts and uses them as primers to initiate transcription and replication of the viral genome in the cytoplasm of infected cells. Hantavirus nucleocapsid protein (N protein) binds to the 5' caps of host cell mRNA and protects them from the attack of cellular decapping machinery. N protein rescues long capped mRNA fragments in cellular P bodies that are later processed by an unknown mechanism to generate 10- to 14-nucleotide-long capped RNA primers with a 3' G residue. Hantavirus RdRp has an N-terminal endonuclease domain and a C-terminal uncharacterized domain that harbors a binding site for the N protein. The purified endonuclease domain of RdRp nonspecifically degraded RNA in vitro It is puzzling how such nonspecific endonuclease activity generates primers of appropriate length and specificity during cap snatching. We fused the N-terminal endonuclease domain with the C-terminal uncharacterized domain of the RdRp. The resulting NC mutant, with the assistance of N protein, generated capped primers of appropriate length and specificity from a test mRNA in cells. Bacterially expressed and purified NC mutant and N protein required further incubation with the lysates of human umbilical vein endothelial cells (HUVECs) for the specific endonucleolytic cleavage of a test mRNA to generate capped primers of appropriate length and defined 3' terminus in vitro Our results suggest that an unknown host cell factor facilitates the interaction between N protein and NC mutant and brings the N protein-bound capped RNA fragments in close proximity to the endonuclease domain of the RdRp for specific cleavage at a precise length from the 5' cap. These studies provide critical insights into the cap-snatching mechanism of cytoplasmic viruses and have revealed potential new targets for their therapeutic intervention.IMPORTANCE Humans acquire hantavirus infection by the inhalation of aerosolized excreta of infected rodent hosts. Hantavirus infections cause hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS), with mortality rates of 15% and 50%, respectively (1). Annually 150,000 to 200,000 cases of hantavirus infections are reported worldwide, for which there is no treatment at present. Cap snatching is an early event in the initiation of virus replication in infected hosts. Interruption in cap snatching will inhibit virus replication and will likely improve the prognosis of the hantavirus disease. Our studies provide mechanistic insight into the cap-snatching mechanism and demonstrate the requirement of a host cell factor for successful cap snatching. Identification of this host cell factor will reveal a novel therapeutic target for combating this viral illness.
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Characterization of an endonuclease in rice stripe tenuivirus Pc1 in vitro. Virus Res 2019; 260:33-37. [DOI: 10.1016/j.virusres.2018.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/11/2018] [Accepted: 11/11/2018] [Indexed: 01/31/2023]
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Holm T, Kopicki JD, Busch C, Olschewski S, Rosenthal M, Uetrecht C, Günther S, Reindl S. Biochemical and structural studies reveal differences and commonalities among cap-snatching endonucleases from segmented negative-strand RNA viruses. J Biol Chem 2018; 293:19686-19698. [PMID: 30348898 PMCID: PMC6314124 DOI: 10.1074/jbc.ra118.004373] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/20/2018] [Indexed: 12/22/2022] Open
Abstract
Viruses rely on many host cell processes, including the cellular transcription machinery. Segmented negative-strand RNA viruses (sNSV) in particular cannot synthesize the 5'-cap structure for their mRNA but cleave off cellular caps and use the resulting oligonucleotides as primers for their transcription. This cap-snatching mechanism, involving a viral cap-binding site and RNA endonuclease, is both virus-specific and essential for viral proliferation and therefore represents an attractive drug target. Here, we present biochemical and structural results on the putative cap-snatching endonuclease of Crimean-Congo hemorrhagic fever virus (CCHFV), a highly pathogenic bunyavirus belonging to the Nairoviridae family, and of two additional nairoviruses, Erve virus (EREV) and Nairobi sheep disease virus (NSDV). Our findings are presented in the context of other cap-snatching endonucleases, such as the enzymatically active endonuclease from Rift Valley fever virus (RVFV), from Arenaviridae and Bunyavirales, belonging to the His- and His+ endonucleases, respectively, according to the absence or presence of a metal ion-coordinating histidine in the active site. Mutational and metal-binding experiments revealed the presence of only acidic metal-coordinating residues in the active site of the CCHFV domain and a unique active-site conformation that was intermediate between those of His+ and His- endonucleases. On the basis of small-angle X-ray scattering (SAXS) and homology modeling results, we propose a protein topology for the CCHFV domain that, despite its larger size, has a structure overall similar to those of related endonucleases. These results suggest structural and functional conservation of the cap-snatching mechanism among sNSVs.
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Affiliation(s)
- Tobias Holm
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Janine-Denise Kopicki
- the Heinrich Pette Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany, and
| | - Carola Busch
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Silke Olschewski
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Maria Rosenthal
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Charlotte Uetrecht
- the Heinrich Pette Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany, and
- the European XFEL GmbH, 22869 Schenefeld, Germany
| | - Stephan Günther
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Sophia Reindl
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany,
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Sun Y, Li J, Gao GF, Tien P, Liu W. Bunyavirales ribonucleoproteins: the viral replication and transcription machinery. Crit Rev Microbiol 2018. [PMID: 29516765 DOI: 10.1080/1040841x.2018.1446901] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The Bunyavirales order is one of the largest groups of segmented negative-sense single-stranded RNA viruses, which includes many pathogenic strains that cause severe human diseases. The RNA segments of the bunyavirus genome are separately encapsidated by multiple copies of nucleoprotein (N), and both termini of each N-encapsidated genomic RNA segment bind to one copy of the viral L polymerase protein. The viral genomic RNA, N and L protein together form the ribonucleoprotein (RNP) complex that constitutes the molecular machinery for viral genome replication and transcription. Recently, breakthroughs have been achieved in understanding the architecture of bunyavirus RNPs with the determination of the atomic structures of the N and L proteins from various members of this order. In this review, we discuss the structures and functions of these bunyavirus RNP components, as well as viral genome replication and transcription mechanisms.
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Affiliation(s)
- Yeping Sun
- a CAS Key Laboratory of Pathogenic Microbiology and Immunology , Institute of Microbiology, Chinese Academy of Sciences , Beijing , China
| | - Jing Li
- a CAS Key Laboratory of Pathogenic Microbiology and Immunology , Institute of Microbiology, Chinese Academy of Sciences , Beijing , China
| | - George F Gao
- a CAS Key Laboratory of Pathogenic Microbiology and Immunology , Institute of Microbiology, Chinese Academy of Sciences , Beijing , China.,b National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention , Beijing , China
| | - Po Tien
- a CAS Key Laboratory of Pathogenic Microbiology and Immunology , Institute of Microbiology, Chinese Academy of Sciences , Beijing , China
| | - Wenjun Liu
- a CAS Key Laboratory of Pathogenic Microbiology and Immunology , Institute of Microbiology, Chinese Academy of Sciences , Beijing , China
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Rosenthal M, Gogrefe N, Vogel D, Reguera J, Rauschenberger B, Cusack S, Günther S, Reindl S. Structural insights into reptarenavirus cap-snatching machinery. PLoS Pathog 2017; 13:e1006400. [PMID: 28505175 PMCID: PMC5444859 DOI: 10.1371/journal.ppat.1006400] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 05/25/2017] [Accepted: 05/05/2017] [Indexed: 01/15/2023] Open
Abstract
Cap-snatching was first discovered in influenza virus. Structures of the involved domains of the influenza virus polymerase, namely the endonuclease in the PA subunit and the cap-binding domain in the PB2 subunit, have been solved. Cap-snatching endonucleases have also been demonstrated at the very N-terminus of the L proteins of mammarena-, orthobunya-, and hantaviruses. However, a cap-binding domain has not been identified in an arena- or bunyavirus L protein so far. We solved the structure of the 326 C-terminal residues of the L protein of California Academy of Sciences virus (CASV), a reptarenavirus, by X-ray crystallography. The individual domains of this 37-kDa fragment (L-Cterm) as well as the domain arrangement are structurally similar to the cap-binding and adjacent domains of influenza virus polymerase PB2 subunit, despite the absence of sequence homology, suggesting a common evolutionary origin. This enabled identification of a region in CASV L-Cterm with similarity to a cap-binding site; however, the typical sandwich of two aromatic residues was missing. Consistent with this, cap-binding to CASV L-Cterm could not be detected biochemically. In addition, we solved the crystal structure of the corresponding endonuclease in the N-terminus of CASV L protein. It shows a typical endonuclease fold with an active site configuration that is essentially identical to that of known mammarenavirus endonuclease structures. In conclusion, we provide evidence for a presumably functional cap-snatching endonuclease in the N-terminus and a degenerate cap-binding domain in the C-terminus of a reptarenavirus L protein. Implications of these findings for the cap-snatching mechanism in arenaviruses are discussed.
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Affiliation(s)
- Maria Rosenthal
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Nadja Gogrefe
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Dominik Vogel
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Juan Reguera
- Aix-Marseille Université, INSERM, CNRS, AFMB UMR 7257, Marseille, France
| | - Bianka Rauschenberger
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, Grenoble, France
| | - Stephan Günther
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Sophia Reindl
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
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Ferron F, Weber F, de la Torre JC, Reguera J. Transcription and replication mechanisms of Bunyaviridae and Arenaviridae L proteins. Virus Res 2017; 234:118-134. [PMID: 28137457 PMCID: PMC7114536 DOI: 10.1016/j.virusres.2017.01.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/17/2017] [Accepted: 01/21/2017] [Indexed: 12/15/2022]
Abstract
Bunyavirus and arenavirus are important public health threats. Bunyavirus and arenavirus molecular biology, common and differential features. Implications of LACV L protein structure for understanding viral RNA synthesis. Current state and future perspectives on bunya- and arenavirus antivirals.
Bunyaviridae and Arenaviridae virus families include an important number of highly pathogenic viruses for humans. They are enveloped viruses with negative stranded RNA genomes divided into three (bunyaviruses) or two (arenaviruses) segments. Each genome segment is coated by the viral nucleoproteins (NPs) and the polymerase (L protein) to form a functional ribonucleoprotein (RNP) complex. The viral RNP provides the necessary context on which the L protein carries out the biosynthetic processes of RNA replication and gene transcription. Decades of research have provided a good understanding of the molecular processes underlying RNA synthesis, both RNA replication and gene transcription, for these two families of viruses. In this review we will provide a global view of the common features, as well as differences, of the molecular biology of Bunyaviridae and Arenaviridae. We will also describe structures of protein and protein-RNA complexes so far determined for these viral families, mainly focusing on the L protein, and discuss their implications for understanding the mechanisms of viral RNA replication and gene transcription within the architecture of viral RNPs, also taking into account the cellular context in which these processes occur. Finally, we will discuss the implications of these structural findings for the development of antiviral drugs to treat human diseases caused by members of the Bunyaviridae and Arenaviridae families.
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Affiliation(s)
- François Ferron
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseille, France; CNRS, AFMB UMR 7257, 13288 Marseille, France
| | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, D-35392 Giessen, Germany
| | | | - Juan Reguera
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseille, France; CNRS, AFMB UMR 7257, 13288 Marseille, France; INSERM, AFMB UMR 7257, 13288 Marseille, France.
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Reguera J, Gerlach P, Rosenthal M, Gaudon S, Coscia F, Günther S, Cusack S. Comparative Structural and Functional Analysis of Bunyavirus and Arenavirus Cap-Snatching Endonucleases. PLoS Pathog 2016; 12:e1005636. [PMID: 27304209 PMCID: PMC4909276 DOI: 10.1371/journal.ppat.1005636] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/25/2016] [Indexed: 01/15/2023] Open
Abstract
Segmented negative strand RNA viruses of the arena-, bunya- and orthomyxovirus families uniquely carry out viral mRNA transcription by the cap-snatching mechanism. This involves cleavage of host mRNAs close to their capped 5′ end by an endonuclease (EN) domain located in the N-terminal region of the viral polymerase. We present the structure of the cap-snatching EN of Hantaan virus, a bunyavirus belonging to hantavirus genus. Hantaan EN has an active site configuration, including a metal co-ordinating histidine, and nuclease activity similar to the previously reported La Crosse virus and Influenza virus ENs (orthobunyavirus and orthomyxovirus respectively), but is more active in cleaving a double stranded RNA substrate. In contrast, Lassa arenavirus EN has only acidic metal co-ordinating residues. We present three high resolution structures of Lassa virus EN with different bound ion configurations and show in comparative biophysical and biochemical experiments with Hantaan, La Crosse and influenza ENs that the isolated Lassa EN is essentially inactive. The results are discussed in the light of EN activation mechanisms revealed by recent structures of full-length influenza virus polymerase. Segmented negative strand viruses (sNSV) such as Influenza, Lassa or Hantaan viruses are responsible for a large number of severe human infectious diseases. Currently, there are vaccines and antiviral treatments available for influenza but none for the infections caused by other sNSV. All carry out transcription by the cap-snatching mechanism, which requires the action of a metal ion dependent endonuclease (EN), a domain within their large viral polymerases. Here we provide the crystal structure of the Hantaan virus (family Bunyaviridae) and Lassa virus (family Arenaviridae) cap-snatching ENs in complex with manganese and a comparative functional study of their catalytic activity. Despite the high structural homology between the two ENs a few changes in the active site, involving a catalytic histidine, cause a different binding of the metal ions with dramatic consequences for their in vitro activity. Hantaan EN binds the metal ions as Influenza A (family Orthomyxoviridae) and LACV (family Bunyaviridae) ENs and all three are active in vitro. In contrast Lassa virus EN is inactive in the same experimental conditions. We can now classify sNSV into two functionally distinct groups (His+ and His- ENs), providing a broad view of the sNSV cap-snatching ENs properties that will be determinant for the comprehensive development of broad-spectrum antiviral drugs. These results also have implications for the viral transcription regulation in the light of recent studies on full-length sNSV polymerases.
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Affiliation(s)
- Juan Reguera
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
- Unit of Virus-Host Cell Interactions (UMI 3265), Univ. Grenoble-Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
- * E-mail: (JR); (SC)
| | - Piotr Gerlach
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
- Unit of Virus-Host Cell Interactions (UMI 3265), Univ. Grenoble-Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
| | - Maria Rosenthal
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Stephanie Gaudon
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
- Unit of Virus-Host Cell Interactions (UMI 3265), Univ. Grenoble-Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
| | - Francesca Coscia
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
- Unit of Virus-Host Cell Interactions (UMI 3265), Univ. Grenoble-Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
| | - Stephan Günther
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
- Unit of Virus-Host Cell Interactions (UMI 3265), Univ. Grenoble-Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9, France
- * E-mail: (JR); (SC)
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