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Sänger L, Williams HM, Yu D, Vogel D, Kosinski J, Rosenthal M, Uetrecht C. RNA to Rule Them All: Critical Steps in Lassa Virus Ribonucleoparticle Assembly and Recruitment. J Am Chem Soc 2023; 145:27958-27974. [PMID: 38104324 PMCID: PMC10755698 DOI: 10.1021/jacs.3c07325] [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: 07/10/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023]
Abstract
Lassa virus is a negative-strand RNA virus with only four structural proteins that causes periodic outbreaks in West Africa. The nucleoprotein (NP) encapsidates the viral genome, forming ribonucleoprotein complexes (RNPs) together with the viral RNA and the L protein. RNPs must be continuously restructured during viral genome replication and transcription. The Z protein is important for membrane recruitment of RNPs, viral particle assembly, and budding and has also been shown to interact with the L protein. However, the interaction of NP, viral RNA, and Z is poorly understood. Here, we characterize the interactions between Lassa virus NP, Z, and RNA using structural mass spectrometry. We identify the presence of RNA as the driver for the disassembly of ring-like NP trimers, a storage form, into monomers to subsequently form higher order RNA-bound NP assemblies. We locate the interaction site of Z and NP and demonstrate that while NP binds Z independently of the presence of RNA, this interaction is pH-dependent. These data improve our understanding of RNP assembly, recruitment, and release in Lassa virus.
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Affiliation(s)
- Lennart Sänger
- Bernhard
Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
- CSSB
Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany
- Leibniz
Institute of Virology (LIV), Notkestraße 85, 22607 Hamburg, Germany
| | - Harry M. Williams
- Bernhard
Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
- CSSB
Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany
| | - Dingquan Yu
- CSSB
Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany
- European
Molecular Biology Laboratory Notkestraße 85, 22607 Hamburg, Germany
| | - Dominik Vogel
- Bernhard
Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
| | - Jan Kosinski
- CSSB
Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany
- European
Molecular Biology Laboratory Notkestraße 85, 22607 Hamburg, Germany
- Structural
and Computational Biology Unit, European
Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Maria Rosenthal
- Bernhard
Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
- CSSB
Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany
- Fraunhofer
Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Schnackenburgallee 114, 22525 Hamburg, Germany
| | - Charlotte Uetrecht
- CSSB
Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany
- Leibniz
Institute of Virology (LIV), Notkestraße 85, 22607 Hamburg, Germany
- Faculty
V: School of Life Sciences, University of
Siegen, Am Eichenhang 50, 57076 Siegen, Germany
- Deutsches
Elektronen-Synchrotron (DESY), Notkestr. 85, 22607 Hamburg, Germany
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2
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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
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Hopkins FR, Álvarez-Rodríguez B, Heath GR, Panayi K, Hover S, Edwards TA, Barr JN, Fontana J. The Native Orthobunyavirus Ribonucleoprotein Possesses a Helical Architecture. mBio 2022; 13:e0140522. [PMID: 35762594 PMCID: PMC9426602 DOI: 10.1128/mbio.01405-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Bunyavirales order is the largest group of negative-sense RNA viruses, containing many lethal human pathogens for which approved anti-infective measures are not available. The bunyavirus genome consists of multiple negative-sense RNA segments enwrapped by the virus-encoded nucleocapsid protein (NP), which together with the viral polymerase form ribonucleoproteins (RNPs). RNPs represent substrates for RNA synthesis and virion assembly, which require inherent flexibility, consistent with the appearance of RNPs spilled from virions. These observations have resulted in conflicting models describing the overall RNP architecture. Here, we purified RNPs from Bunyamwera virus (BUNV), the prototypical orthobunyavirus. The lengths of purified RNPs imaged by negative staining resulted in 3 populations of RNPs, suggesting that RNPs possess a consistent method of condensation. Employing microscopy approaches, we conclusively show that the NP portion of BUNV RNPs is helical. Furthermore, we present a pseudo-atomic model for this portion based on a cryo-electron microscopy average at 13 Å resolution, which allowed us to fit the BUNV NP crystal structure by molecular dynamics. This model was confirmed by NP mutagenesis using a mini-genome system. The model shows that adjacent NP monomers in the RNP chain interact laterally through flexible N- and C-terminal arms only, with no longitudinal helix-stabilizing interactions, thus providing a potential model for the molecular basis for RNP flexibility. Excessive RNase treatment disrupts native RNPs, suggesting that RNA was key in maintaining the RNP structure. Overall, this work will inform studies on bunyaviral RNP assembly, packaging, and RNA replication, and aid in future antiviral strategies. IMPORTANCE Bunyaviruses are emerging RNA viruses that cause significant disease and economic burden and for which vaccines or therapies approved for humans are not available. The bunyavirus genome is wrapped up by the nucleoprotein (NP) and interacts with the viral polymerase, forming a ribonucleoprotein (RNP). This is the only form of the genome active for viral replication and assembly. However, until now how NPs are organized within an RNP was not known for any orthobunyavirus. Here, we purified RNPs from the prototypical orthobunyavirus, Bunyamwera virus, and employed microscopy approaches to show that the NP portion of the RNP was helical. We then combined our helical average with the known structure of an NP monomer, generating a pseudo-atomic model of this region. This arrangement allowed the RNPs to be highly flexible, which was critical for several stages of the viral replication cycle, such as segment circularization.
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Affiliation(s)
- Francis R. Hopkins
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
| | - Beatriz Álvarez-Rodríguez
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
| | - George R. Heath
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
| | - Kyriakoulla Panayi
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
| | - Samantha Hover
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
| | - Thomas A. Edwards
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
| | - John N. Barr
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
| | - Juan Fontana
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leedsgrid.9909.9, Leeds, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leedsgrid.9909.9, Leeds, United Kingdom
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Fang J, Pietzsch C, Witwit H, Tsaprailis G, Crynen G, Cho KF, Ting AY, Bukreyev A, Saphire EO, de la Torre JC. Proximity interactome analysis of Lassa polymerase reveals eRF3a/GSPT1 as a druggable target for host-directed antivirals. Proc Natl Acad Sci U S A 2022; 119:e2201208119. [PMID: 35858434 PMCID: PMC9340056 DOI: 10.1073/pnas.2201208119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/24/2022] [Indexed: 01/21/2023] Open
Abstract
Completion of the Lassa virus (LASV) life cycle critically depends on the activities of the virally encoded, RNA-dependent RNA polymerase in replication and transcription of the viral RNA genome in the cytoplasm of infected cells. The contribution of cellular proteins to these processes remains unclear. Here, we applied proximity proteomics to define the interactome of LASV polymerase in cells under conditions that recreate LASV RNA synthesis. We engineered a LASV polymerase-biotin ligase (TurboID) fusion protein that retained polymerase activity and successfully biotinylated the proximal proteome, which allowed the identification of 42 high-confidence LASV polymerase interactors. We subsequently performed a small interfering RNA (siRNA) screen to identify those interactors that have functional roles in authentic LASV infection. As proof of principle, we characterized eukaryotic peptide chain release factor subunit 3a (eRF3a/GSPT1), which we found to be a proviral factor that physically associates with LASV polymerase. Targeted degradation of GSPT1 by a small-molecule drug candidate, CC-90009, resulted in strong inhibition of LASV infection in cultured cells. Our work demonstrates the feasibility of using proximity proteomics to illuminate and characterize yet-to-be-defined host-pathogen interactome, which can reveal new biology and uncover novel targets for the development of antivirals against highly pathogenic RNA viruses.
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Affiliation(s)
- Jingru Fang
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037
- La Jolla Institute for Immunology, La Jolla, CA 92037
| | - Colette Pietzsch
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77550
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77550
| | - Haydar Witwit
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037
| | | | - Gogce Crynen
- Bioinformatics and Statistics Core, Scripps Research, Jupiter, FL 33458
| | | | - Alice Y. Ting
- Department of Genetics, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Chan Zuckerberg Biohub, San Francisco, CA 94158
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77550
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77550
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77550
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Gallo GL, López N, Loureiro ME. The Virus–Host Interplay in Junín Mammarenavirus Infection. Viruses 2022; 14:v14061134. [PMID: 35746604 PMCID: PMC9228484 DOI: 10.3390/v14061134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 02/06/2023] Open
Abstract
Junín virus (JUNV) belongs to the Arenaviridae family and is the causative agent of Argentine hemorrhagic fever (AHF), a severe human disease endemic to agricultural areas in Argentina. At this moment, there are no effective antiviral therapeutics to battle pathogenic arenaviruses. Cumulative reports from recent years have widely provided information on cellular factors playing key roles during JUNV infection. In this review, we summarize research on host molecular determinants that intervene in the different stages of the viral life cycle: viral entry, replication, assembly and budding. Alongside, we describe JUNV tight interplay with the innate immune system. We also review the development of different reverse genetics systems and their use as tools to study JUNV biology and its close teamwork with the host. Elucidating relevant interactions of the virus with the host cell machinery is highly necessary to better understand the mechanistic basis beyond virus multiplication, disease pathogenesis and viral subversion of the immune response. Altogether, this knowledge becomes essential for identifying potential targets for the rational design of novel antiviral treatments to combat JUNV as well as other pathogenic arenaviruses.
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