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Xie J, Ouizougun-Oubari M, Wang L, Zhai G, Wu D, Lin Z, Wang M, Ludeke B, Yan X, Nilsson T, Gao L, Huang X, Fearns R, Chen S. Structural basis for dimerization of a paramyxovirus polymerase complex. Nat Commun 2024; 15:3163. [PMID: 38605025 PMCID: PMC11009304 DOI: 10.1038/s41467-024-47470-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/26/2024] [Indexed: 04/13/2024] Open
Abstract
The transcription and replication processes of non-segmented, negative-strand RNA viruses (nsNSVs) are catalyzed by a multi-functional polymerase complex composed of the large protein (L) and a cofactor protein, such as phosphoprotein (P). Previous studies have shown that the nsNSV polymerase can adopt a dimeric form, however, the structure of the dimer and its function are poorly understood. Here we determine a 2.7 Å cryo-EM structure of human parainfluenza virus type 3 (hPIV3) L-P complex with the connector domain (CD') of a second L built, while reconstruction of the rest of the second L-P obtains a low-resolution map of the ring-like L core region. This study reveals detailed atomic features of nsNSV polymerase active site and distinct conformation of hPIV3 L with a unique β-strand latch. Furthermore, we report the structural basis of L-L dimerization, with CD' located at the putative template entry of the adjoining L. Disruption of the L-L interface causes a defect in RNA replication that can be overcome by complementation, demonstrating that L dimerization is necessary for hPIV3 genome replication. These findings provide further insight into how nsNSV polymerases perform their functions, and suggest a new avenue for rational drug design.
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Affiliation(s)
- Jin Xie
- Roche Pharma Research and Early Development, Lead Discovery, Roche Innovation Center Shanghai, 201203, Shanghai, China
| | - Mohamed Ouizougun-Oubari
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Li Wang
- Roche Pharma Research and Early Development, Infectious Diseases, Roche Innovation Center Shanghai, 201203, Shanghai, China
| | - Guanglei Zhai
- Roche Pharma Research and Early Development, Lead Discovery, Roche Innovation Center Shanghai, 201203, Shanghai, China
| | - Daitze Wu
- Roche Pharma Research and Early Development, Infectious Diseases, Roche Innovation Center Shanghai, 201203, Shanghai, China
| | - Zhaohu Lin
- Roche Pharma Research and Early Development, Lead Discovery, Roche Innovation Center Shanghai, 201203, Shanghai, China
| | - Manfu Wang
- Wuxi Biortus Biosciences Co. Ltd., 214437, Jiangyin, Jiangsu, China
| | - Barbara Ludeke
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Xiaodong Yan
- Wuxi Biortus Biosciences Co. Ltd., 214437, Jiangyin, Jiangsu, China
| | - Tobias Nilsson
- Roche Pharma Research and Early Development, Infectious Diseases, Roche Innovation Center Basel, Basel, 4070, Switzerland
| | - Lu Gao
- Roche Pharma Research and Early Development, Infectious Diseases, Roche Innovation Center Shanghai, 201203, Shanghai, China.
| | - Xinyi Huang
- Roche Pharma Research and Early Development, Lead Discovery, Roche Innovation Center Shanghai, 201203, Shanghai, China.
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA.
| | - Shuai Chen
- Roche Pharma Research and Early Development, Lead Discovery, Roche Innovation Center Shanghai, 201203, Shanghai, China.
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Abduljalil JM, Elfiky AA, Sayed ESTA, AlKhazindar MM. In silico structural elucidation of Nipah virus L protein and targeting RNA-dependent RNA polymerase domain by nucleoside analogs. J Biomol Struct Dyn 2023; 41:8215-8229. [PMID: 36205638 DOI: 10.1080/07391102.2022.2130987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 09/25/2022] [Indexed: 10/10/2022]
Abstract
The large (L) protein of Mononegavirales is a multi-domain protein that performs transcription and genome replication. One of the important domains in L is the RNA-dependent RNA polymerase (RdRp), a promising target for antiviral drugs. In this work, we employed rigorous computational comparative modeling to predict the structure of L protein of Nipah virus (NiV). The RdRp domain was targeted by a panel of nucleotide analogs, previously reported to inhibit different viral RNA polymerases, using molecular docking. Best binder compounds were subjected to molecular dynamics simulation to validate their binding. Molecular mechanics/generalized-born surface area (MM/GBSA) calculations estimated the binding free energy. The predicted model of NiV L has an excellent quality as judged by physics- and knowledge-based validation tests. Galidesivir, AT-9010 and Norov-29 scored the top nucleotide analogs to bind to the RdRp. Their binding free energies obtained by MM/GBSA (-31.01 ± 3.9 to -38.37 ± 4.8 kcal/mol) ranked Norov-29 as the best potential inhibitor. Purine nucleotide analogs are expected to harbor the scaffold for an effective drug against NiV. Finally, this study is expected to provide a start point for medicinal chemistry and drug discovery campaigns toward identification of effective chemotherapeutic agent(s) against NiV.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Jameel M Abduljalil
- Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza, Egypt
- Department of Biological Sciences, Faculty of Applied Sciences, Thamar University, Dhamar, Yemen
| | - Abdo A Elfiky
- Department of Biophysics, Faculty of Science, Cairo University, Giza, Egypt
| | - El-Sayed T A Sayed
- Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza, Egypt
| | - Maha M AlKhazindar
- Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza, Egypt
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3
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Abstract
The nonsegmented, negative-strand RNA viruses (nsNSVs), also known as the order Mononegavirales, have a genome consisting of a single strand of negative-sense RNA. Integral to the nsNSV replication cycle is the viral polymerase, which is responsible for transcribing the viral genome, to produce an array of capped and polyadenylated messenger RNAs, and replicating it to produce new genomes. To perform the different steps that are necessary for these processes, the nsNSV polymerases undergo a series of coordinated conformational transitions. While much is still to be learned regarding the intersection of nsNSV polymerase dynamics, structure, and function, recently published polymerase structures, combined with a history of biochemical and molecular biology studies, have provided new insights into how nsNSV polymerases function as dynamic machines. In this review, we consider each of the steps involved in nsNSV transcription and replication and suggest how these relate to solved polymerase structures.
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Affiliation(s)
- Mohamed Ouizougun-Oubari
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA;
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA;
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Sutto-Ortiz P, Eléouët JF, Ferron F, Decroly E. Biochemistry of the Respiratory Syncytial Virus L Protein Embedding RNA Polymerase and Capping Activities. Viruses 2023; 15:v15020341. [PMID: 36851554 PMCID: PMC9960070 DOI: 10.3390/v15020341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/12/2023] [Accepted: 01/21/2023] [Indexed: 01/27/2023] Open
Abstract
The human respiratory syncytial virus (RSV) is a negative-sense, single-stranded RNA virus. It is the major cause of severe acute lower respiratory tract infection in infants, the elderly population, and immunocompromised individuals. There is still no approved vaccine or antiviral treatment against RSV disease, but new monoclonal prophylactic antibodies are yet to be commercialized, and clinical trials are in progress. Hence, urgent efforts are needed to develop efficient therapeutic treatments. RSV RNA synthesis comprises viral transcription and replication that are catalyzed by the large protein (L) in coordination with the phosphoprotein polymerase cofactor (P), the nucleoprotein (N), and the M2-1 transcription factor. The replication/transcription is orchestrated by the L protein, which contains three conserved enzymatic domains: the RNA-dependent RNA polymerase (RdRp), the polyribonucleotidyl transferase (PRNTase or capping), and the methyltransferase (MTase) domain. These activities are essential for the RSV replicative cycle and are thus considered as attractive targets for the development of therapeutic agents. In this review, we summarize recent findings about RSV L domains structure that highlight how the enzymatic activities of RSV L domains are interconnected, discuss the most relevant and recent antivirals developments that target the replication/transcription complex, and conclude with a perspective on identified knowledge gaps that enable new research directions.
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Affiliation(s)
| | - Jean-François Eléouët
- Unité de Virologie et Immunologie Moléculaires, INRAE, Université Paris Saclay, F78350 Jouy en Josas, France
| | - François Ferron
- Aix Marseille Université, CNRS, AFMB, UMR, 7257 Marseille, France
- European Virus Bioinformatics Center, Leutragraben 1, 07743 Jena, Germany
| | - Etienne Decroly
- Aix Marseille Université, CNRS, AFMB, UMR, 7257 Marseille, France
- Correspondence:
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5
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Locations and in situ structure of the polymerase complex inside the virion of vesicular stomatitis virus. Proc Natl Acad Sci U S A 2022; 119:e2111948119. [PMID: 35476516 PMCID: PMC9170060 DOI: 10.1073/pnas.2111948119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Unlike fellow nonsegmented negative-strand RNA viruses, exemplified by the devastating Nipah, Ebola, rabies, and measles viruses, vesicular stomatitis virus (VSV) can be considered beneficial, as it is widely used as a vector for anticancer therapy and vaccine development. In these RNA viruses, transcription and replication of the viral genome depend on an RNA-dependent RNA polymerase. Here, we determined the in situ structure of the VSV polymerase complex, consisting of a large protein (L) and a phosphoprotein (P), by cryo-electron tomography and subtomogram averaging. Approximately 55 polymerase complexes are packaged in each bullet-shaped virion through flexible interactions with nucleoproteins. Our results provide insights into the mechanism of L packaging during virus assembly and efficient initiation of transcription during infection. The polymerase complex of nonsegmented negative-strand RNA viruses primarily consists of a large (L) protein and a phosphoprotein (P). L is a multifunctional enzyme carrying out RNA-dependent RNA polymerization and all other steps associated with transcription and replication, while P is the nonenzymatic cofactor, regulating the function and conformation of L. The structure of a purified vesicular stomatitis virus (VSV) polymerase complex containing L and associated P segments has been determined; however, the location and manner of the attachments of L and P within each virion are unknown, limiting our mechanistic understanding of VSV RNA replication and transcription and hindering engineering efforts of this widely used anticancer and vaccine vector. Here, we have used cryo-electron tomography to visualize the VSV virion, revealing the attachment of the ring-shaped L molecules to VSV nucleocapsid proteins (N) throughout the cavity of the bullet-shaped nucleocapsid. Subtomogram averaging and three-dimensional classification of regions containing N and the matrix protein (M) have yielded the in situ structure of the polymerase complex. On average, ∼55 polymerase complexes are packaged in each virion. The capping domain of L interacts with two neighboring N molecules through flexible attachments. P, which exists as a dimer, bridges separate N molecules and the connector and C-terminal domains of L. Our data provide the structural basis for recruitment of L to N by P in virus assembly and for flexible attachments between L and N, which allow a quick response of L in primary transcription upon cell entry.
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Sakamoto K, Satoh Y, Takahashi KI, Wakimoto H, Kitagawa Y, Gotoh B, Ayata M, Itoh M. Upregulation of viral RNA polymerase activity promotes adaptation of SSPE virus to neuronal cells. Virology 2022; 573:1-11. [DOI: 10.1016/j.virol.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 05/13/2022] [Accepted: 05/24/2022] [Indexed: 11/26/2022]
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Gibbons JS, Khadka S, Williams CG, Wang L, Schneller SW, Liu C, Tufariello JM, Basler CF. Mechanisms of anti-vesicular stomatitis virus activity of deazaneplanocin and its 3-brominated analogs. Antiviral Res 2021; 191:105088. [PMID: 34019950 DOI: 10.1016/j.antiviral.2021.105088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/02/2021] [Accepted: 05/10/2021] [Indexed: 12/30/2022]
Abstract
3-deazaneplanocin A (DzNep) and its 3-brominated analogs inhibit replication of several RNA viruses. This antiviral activity is attributed to inhibition of S-adenosyl homocysteine hydrolase (SAHase) and consequently inhibition of viral methyltransferases, impairing translation of viral transcripts. The L-enantiomers of some derivatives retain antiviral activity despite dramatically reduced inhibition of SAHase in vitro. To better understand the mechanisms by which these compounds exert their antiviral effects, we compared DzNep, its 3-bromo-derivative, CL123, and the related enantiomers, CL4033 and CL4053, for their activities towards the model negative-sense RNA virus vesicular stomatitis virus (VSV). In cell culture, DzNep, CL123 and CL4033 each exhibited 50 percent inhibitory concentrations (IC50s) in the nanomolar range whereas the IC50 for the L-form, CL4053, was 34-85 times higher. When a CL123-resistant mutant (VSVR) was selected, it exhibited cross-resistance to each of the neplanocin analogs, but retained sensitivity to the adenosine analog BCX4430, an RNA chain terminator. Sequencing of VSVR identified a mutation in the C-terminal domain (CTD) of the viral large (L) protein, a domain implicated in regulation of L protein methyltransferase activity. CL123 inhibited VSV viral mRNA 5' cap methylation, impaired viral protein synthesis and decreased association of viral mRNAs with polysomes. Modest impacts on viral transcription were also demonstrated. VSVR exhibited partial resistance in each of these assays but its replication was impaired, relative to the parent VSV, in the absence of the inhibitors. These data suggest that DzNep, CL123 and CL4033 inhibit VSV through impairment of viral mRNA cap methylation and that the L-form, CL4053, based on the cross-resistance of VSVR, may act by a similar mechanism.
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Affiliation(s)
- Joyce Sweeney Gibbons
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA; Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Sudip Khadka
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA; Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Caroline G Williams
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Lin Wang
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA; Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Stewart W Schneller
- Molette Laboratory for Drug Discovery, Department of Chemistry and Biochemistry, Auburn University, Auburn, AL, USA
| | - Chong Liu
- Molette Laboratory for Drug Discovery, Department of Chemistry and Biochemistry, Auburn University, Auburn, AL, USA
| | - JoAnn M Tufariello
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Christopher F Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA.
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Structure of a paramyxovirus polymerase complex reveals a unique methyltransferase-CTD conformation. Proc Natl Acad Sci U S A 2020; 117:4931-4941. [PMID: 32075920 PMCID: PMC7060699 DOI: 10.1073/pnas.1919837117] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Paramyxoviruses are enveloped, nonsegmented, negative-strand RNA viruses that cause a wide spectrum of human and animal diseases. The viral genome, packaged by the nucleoprotein (N), serves as a template for the polymerase complex, composed of the large protein (L) and the homo-tetrameric phosphoprotein (P). The ∼250-kDa L possesses all enzymatic activities necessary for its function but requires P in vivo. Structural information is available for individual P domains from different paramyxoviruses, but how P interacts with L and how that affects the activity of L is largely unknown due to the lack of high-resolution structures of this complex in this viral family. In this study we determined the structure of the L-P complex from parainfluenza virus 5 (PIV5) at 4.3-Å resolution using cryoelectron microscopy, as well as the oligomerization domain (OD) of P at 1.4-Å resolution using X-ray crystallography. P-OD associates with the RNA-dependent RNA polymerase domain of L and protrudes away from it, while the X domain of one chain of P is bound near the L nucleotide entry site. The methyltransferase (MTase) domain and the C-terminal domain (CTD) of L adopt a unique conformation, positioning the MTase active site immediately above the poly-ribonucleotidyltransferase domain and near the likely exit site for the product RNA 5' end. Our study reveals a potential mechanism that mononegavirus polymerases may employ to switch between transcription and genome replication. This knowledge will assist in the design and development of antivirals against paramyxoviruses.
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The Connector Domain of Vesicular Stomatitis Virus Large Protein Interacts with the Viral Phosphoprotein. J Virol 2020; 94:JVI.01729-19. [PMID: 31896592 DOI: 10.1128/jvi.01729-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/16/2019] [Indexed: 11/20/2022] Open
Abstract
Vesicular stomatitis virus (VSV) is an archetypical member of Mononegavirales, viruses with a genome of negative-sense single-stranded RNA (-ssRNA). Like other viruses of this order, VSV encodes a unique polymerase, a complex of viral L (large, the enzymatic component) protein and P (phosphoprotein, a cofactor component). The L protein has a modular layout consisting of a ring-shaped core trailed by three accessory domains and requires an N-terminal segment of P (P N-terminal disordered [PNTD]) to perform polymerase activity. To date, a binding site for P on L had not been described. In this report, we show that the connector domain of the L protein, which previously had no assigned function, binds a component of PNTD We further show that this interaction is a positive regulator of viral RNA synthesis, and that the interfaces mediating it are conserved in other members of Mononegavirales Finally, we show that the connector-P interaction fits well into the existing structural information of VSV L.IMPORTANCE This study represents the first functional assignment of the connector domain of a Mononegavirales L protein. Furthermore, this study localizes P polymerase cofactor activity to specific amino acids. The functional necessity of this interaction, combined with the uniqueness of L and P proteins to the order Mononegavirales, makes disruption of the P-connector site a potential target for developing antivirals against other negative-strand RNA viruses. Furthermore, the connector domain as an acceptor site for the P protein represents a new understanding of Mononegavirales L protein biology.
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Heilmann E, Kimpel J, Geley S, Naschberger A, Urbiola C, Nolden T, von Laer D, Wollmann G. The Methyltransferase Region of Vesicular Stomatitis Virus L Polymerase Is a Target Site for Functional Intramolecular Insertion. Viruses 2019; 11:v11110989. [PMID: 31717818 PMCID: PMC6893670 DOI: 10.3390/v11110989] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/20/2019] [Accepted: 10/23/2019] [Indexed: 11/16/2022] Open
Abstract
The L-protein of vesicular stomatitis virus (VSV) is a single-chain multi-domain RNA-dependent RNA polymerase. Previously reported attempts of intramolecular insertions of fluorescent proteins into the L-protein resulted in temperature-sensitive and highly attenuated polymerase activity. Here, we describe a novel insertion site that was selected based on in silico prediction. Of five preselected locations, insertion of the fluorescent protein mCherry in the VSV polymerase between amino acids 1620 and 1621 preserved polymerase function even after extended passaging and showed only mild attenuation compared to wildtype VSV polymerase. High magnification fluorescence imaging revealed a corpuscular cytosolic pattern for the L-protein. To confirm that the insertion site tolerates inclusion of proteins others than mCherry, we cloned mWasabi into the same position in L, generating a VSV-LmWasabi, which was also functional. We also generated a functional dual-color-dual-insertion VSV construct with intramolecularly labeled P and L-proteins. Together, our data present an approach to tag VSV polymerase intramolecularly without perturbing enzymatic activity. This L fusion protein might enable future tracing studies to monitor intracellular location of the VSV transcription and replication machinery in real-time life-imaging studies.
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Affiliation(s)
- Emmanuel Heilmann
- Division of Virology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (E.H.); (J.K.); (C.U.)
- Christian Doppler Laboratory for Viral Immunotherapy of Cancer, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Janine Kimpel
- Division of Virology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (E.H.); (J.K.); (C.U.)
| | - Stephan Geley
- Division of Molecular Pathophysiology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Andreas Naschberger
- Division of Genetic Epidemiology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Carles Urbiola
- Division of Virology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (E.H.); (J.K.); (C.U.)
- Christian Doppler Laboratory for Viral Immunotherapy of Cancer, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Dorotheé von Laer
- Division of Virology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (E.H.); (J.K.); (C.U.)
- Correspondence: (D.v.L.); (G.W.); Tel.: +43-512-9003-71701 (D.v.L.); +43-512-9003-71742 (G.W.)
| | - Guido Wollmann
- Division of Virology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (E.H.); (J.K.); (C.U.)
- Christian Doppler Laboratory for Viral Immunotherapy of Cancer, Medical University of Innsbruck, 6020 Innsbruck, Austria
- Correspondence: (D.v.L.); (G.W.); Tel.: +43-512-9003-71701 (D.v.L.); +43-512-9003-71742 (G.W.)
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11
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Molecular Function Analysis of Rabies Virus RNA Polymerase L Protein by Using an L Gene-Deficient Virus. J Virol 2017; 91:JVI.00826-17. [PMID: 28768857 DOI: 10.1128/jvi.00826-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/24/2017] [Indexed: 12/25/2022] Open
Abstract
While the RNA-dependent RNA polymerase L protein of rabies virus (RABV), a member of the genus Lyssavirus of the family Rhabdoviridae, has potential to be a therapeutic target for rabies, the molecular functions of this protein have remained largely unknown. In this study, to obtain a novel experimental tool for molecular function analysis of the RABV L protein, we established by using a reverse genetics approach an L gene-deficient RABV (Nishi-ΔL/Nluc), which infects, propagates, and correspondingly produces NanoLuc luciferase in cultured neuroblastoma cells transfected to express the L protein. trans-Complementation with wild-type L protein, but not that with a functionally defective L protein mutant, efficiently supported luciferase production by Nishi-ΔL/Nluc, confirming its potential for function analysis of the L protein. Based on the findings obtained from comprehensive genetic analyses of L genes from various RABV and other lyssavirus species, we examined the functional importance of a highly conserved L protein region at positions 1914 to 1933 by a trans-complementation assay with Nishi-ΔL/Nluc and a series of L protein mutants. The results revealed that the amino acid sequence at positions 1929 to 1933 (NPYNE) is functionally important, and this was supported by other findings that this sequence is critical for binding of the L protein with its essential cofactor, P protein, and thus also for L protein's RNA polymerase activity. Our findings provide useful information for the development of an anti-RABV drug targeting the L-P protein interaction.IMPORTANCE To the best of our knowledge, this is the first report on the establishment of an L gene-deficient, reporter gene-expressing virus in all species of the order Mononegavirales, also highlighting its applicability to a trans-complementation assay, which is useful for molecular function analyses of their L proteins. Moreover, this study revealed for the first time that the NPYNE sequence at positions 1929 to 1933 in the RABV L protein is important for L protein's interaction with the P protein, consistent with and extending the results of a previous study showing that the P protein-binding domain in the L protein is located in its C-terminal region, at positions 1562 to 2127. This study indicates that the NPYNE sequence is a promising target for the development of an inhibitor of viral RNA synthesis, which has high potential as a therapeutic drug for rabies.
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12
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Ruedas JB, Connor JH. Generating Recombinant Vesicular Stomatitis Viruses for Use as Vaccine Platforms. Methods Mol Biol 2017; 1581:203-222. [PMID: 28374251 DOI: 10.1007/978-1-4939-6869-5_12] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The unique properties of vesicular stomatitis virus (VSV) make it a promising vaccine platform. With the advent of plasmid-based approaches to generate recombinant VSV viruses that express glycoproteins of other viruses, researchers now have the means to generate vaccine candidates targeting a variety of human pathogens. This chapter gives a general overview of the workings of VSV as a vaccine platform and provides a detailed protocol for the generation of recombinant VSV from plasmids.
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Affiliation(s)
- John B Ruedas
- Department of Microbiology and National Emerging Infectious Disease Laboratory, Boston University School of Medicine, Boston, MA, USA
| | - John H Connor
- Department of Microbiology and National Emerging Infectious Disease Laboratory, Boston University School of Medicine, Boston, MA, USA.
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