1
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Gu Y, Lozach PY. Illuminating bunyavirus entry into host cells with fluorescence. Mol Microbiol 2024; 121:671-678. [PMID: 37700704 DOI: 10.1111/mmi.15165] [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: 07/18/2023] [Revised: 09/02/2023] [Accepted: 09/04/2023] [Indexed: 09/14/2023]
Abstract
Bunyavirales constitute the largest order of enveloped RNA viruses, many members of which cause severe diseases in humans and domestic animals. In recent decades, innovative fluorescence-based methods have paved the way to visualize and track single fluorescent bunyaviral particles in fixed and live cells. This technological breakthrough has enabled imaging of the early stages of infection and the quantification of every step in the bunyavirus cell entry process. Here, we describe the latest procedures for rendering bunyaviral particles fluorescent and discuss the advantages and disadvantages of each approach in light of the most recent advances in fluorescence detection and monitoring of bunyavirus entry. In this mini-review, we also illustrate how fluorescent viral particles are a powerful tool for deciphering the cellular entry process of bunyaviruses, the vast majority of which have not yet been analyzed.
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Affiliation(s)
- Yu Gu
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, Lyon, France
| | - Pierre-Yves Lozach
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, Lyon, France
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2
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Uckeley ZM, Duboeuf M, Gu Y, Erny A, Mazelier M, Lüchtenborg C, Winter SL, Schad P, Mathieu C, Koch J, Boulant S, Chlanda P, Maisse C, Brügger B, Lozach PY. Glucosylceramide in bunyavirus particles is essential for virus binding to host cells. Cell Mol Life Sci 2024; 81:71. [PMID: 38300320 PMCID: PMC10834583 DOI: 10.1007/s00018-023-05103-0] [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: 09/23/2023] [Revised: 12/08/2023] [Accepted: 12/21/2023] [Indexed: 02/02/2024]
Abstract
Hexosylceramides (HexCer) are implicated in the infection process of various pathogens. However, the molecular and cellular functions of HexCer in infectious cycles are poorly understood. Investigating the enveloped virus Uukuniemi (UUKV), a bunyavirus of the Phenuiviridae family, we performed a lipidomic analysis with mass spectrometry and determined the lipidome of both infected cells and derived virions. We found that UUKV alters the processing of HexCer to glycosphingolipids (GSL) in infected cells. The infection resulted in the overexpression of glucosylceramide (GlcCer) synthase (UGCG) and the specific accumulation of GlcCer and its subsequent incorporation into viral progeny. UUKV and several pathogenic bunyaviruses relied on GlcCer in the viral envelope for binding to various host cell types. Overall, our results indicate that GlcCer is a structural determinant of virions crucial for bunyavirus infectivity. This study also highlights the importance of glycolipids on virions in facilitating interactions with host cell receptors and infectious entry of enveloped viruses.
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Affiliation(s)
- Zina M Uckeley
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, 69120, Heidelberg, Germany
- Cluster of Excellence, CellNetworks, 69120, Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany
- Department for Molecular Genetics and Microbiology, University of Florida, Gainesville, USA
| | - Maëva Duboeuf
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, 69007, Lyon, France
| | - Yu Gu
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, 69007, Lyon, France
| | - Alexandra Erny
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, 69007, Lyon, France
| | - Magalie Mazelier
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, 69120, Heidelberg, Germany
- Cluster of Excellence, CellNetworks, 69120, Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | | | - Sophie L Winter
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, 69120, Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - Paulina Schad
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, 69120, Heidelberg, Germany
- Cluster of Excellence, CellNetworks, 69120, Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Cyrille Mathieu
- CIRI (Centre International de Recherche en Infectiologie), Team Neuro-Invasion, TROpism and VIRal Encephalitis, INSERM U1111, CNRS UMR5308, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 69007, Lyon, France
| | - Jana Koch
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, 69120, Heidelberg, Germany
- Cluster of Excellence, CellNetworks, 69120, Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, 69007, Lyon, France
| | - Steeve Boulant
- Department for Molecular Genetics and Microbiology, University of Florida, Gainesville, USA
| | - Petr Chlanda
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, 69120, Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - Carine Maisse
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, 69007, Lyon, France
| | - Britta Brügger
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Pierre-Yves Lozach
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, 69120, Heidelberg, Germany.
- Cluster of Excellence, CellNetworks, 69120, Heidelberg, Germany.
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany.
- Université Claude Bernard Lyon 1, INRAE, EPHE, IVPC UMR754, Team iWays, 69007, Lyon, France.
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3
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Mueller F, Witteveldt J, Macias S. Antiviral Defence Mechanisms during Early Mammalian Development. Viruses 2024; 16:173. [PMID: 38399949 PMCID: PMC10891733 DOI: 10.3390/v16020173] [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: 12/14/2023] [Revised: 01/11/2024] [Accepted: 01/20/2024] [Indexed: 02/25/2024] Open
Abstract
The type-I interferon (IFN) response constitutes the major innate immune pathway against viruses in mammals. Despite its critical importance for antiviral defence, this pathway is inactive during early embryonic development. There seems to be an incompatibility between the IFN response and pluripotency, the ability of embryonic cells to develop into any cell type of an adult organism. Instead, pluripotent cells employ alternative ways to defend against viruses that are typically associated with safeguard mechanisms against transposable elements. The absence of an inducible IFN response in pluripotent cells and the constitutive activation of the alternative antiviral pathways have led to the hypothesis that embryonic cells are highly resistant to viruses. However, some findings challenge this interpretation. We have performed a meta-analysis that suggests that the susceptibility of pluripotent cells to viruses is directly correlated with the presence of receptors or co-receptors for viral adhesion and entry. These results challenge the current view of pluripotent cells as intrinsically resistant to infections and raise the fundamental question of why these cells have sacrificed the major antiviral defence pathway if this renders them susceptible to viruses.
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Affiliation(s)
- Felix Mueller
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King’s Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; (F.M.); (J.W.)
- Centre for Virus Research, MRC-University of Glasgow, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - Jeroen Witteveldt
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King’s Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; (F.M.); (J.W.)
| | - Sara Macias
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King’s Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; (F.M.); (J.W.)
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4
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Thannickal SA, Spector SN, Stapleford KA. The La Crosse virus class II fusion glycoprotein ij loop contributes to infectivity and replication in vitro and in vivo. J Virol 2023; 97:e0081923. [PMID: 37578236 PMCID: PMC10506486 DOI: 10.1128/jvi.00819-23] [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: 05/31/2023] [Accepted: 07/06/2023] [Indexed: 08/15/2023] Open
Abstract
Arthropod-borne viruses (arboviruses) are an emerging and evolving global public health threat, with limited antiviral treatments or vaccines available. La Crosse virus (LACV) from the Bunyavirales order is responsible for pediatric encephalitis cases in the United States, yet little is known about the infectivity of LACV. Given the structural similarities between class II fusion glycoproteins of LACV and chikungunya virus (CHIKV), an alphavirus from the Togaviridae family, we hypothesized that LACV would share similar entry mechanisms with CHIKV. To test this hypothesis, we performed cholesterol-depletion and repletion assays and used cholesterol-modulating compounds to study LACV entry and replication. We found that LACV entry was cholesterol dependent, while replication was less affected by cholesterol manipulation. In addition, we generated single-point mutants in the LACV Gc ij loop that corresponded to known CHIKV residues important for virus entry. We found that a conserved histidine and alanine residue in the Gc ij loop impaired virus infectivity and attenuated LACV replication in vitro and in vivo. Finally, we took an evolution-based approach to explore how the LACV glycoprotein evolves in mosquitoes and mice. We found multiple variants that cluster in the Gc glycoprotein head domain, providing evidence for the Gc glycoprotein as a contributor to LACV adaptation. Together, these results begin to characterize the mechanisms of LACV infectivity and how the LACV glycoprotein contributes to replication and pathogenesis. IMPORTANCE Vector-borne viruses are significant health threats that lead to devastating disease worldwide. The emergence of arboviruses, in addition to the lack of effective antivirals or vaccines, highlights the need to study how arboviruses replicate at the molecular level. One potential antiviral target is the class II fusion glycoprotein. Alphaviruses, flaviviruses, and bunyaviruses encode a class II fusion glycoprotein that contains strong structural similarities at the tip of domain II. Here, we show that the bunyavirus La Crosse virus uses a cholesterol-dependent entry pathway similar to the alphavirus chikungunya virus, and residues in the ij loop are important for virus infectivity in vitro and replication in mice. These studies show that genetically diverse viruses may use similar pathways through conserved structure domains, suggesting that these viruses may be targets for broad-spectrum antivirals in multiple arboviral families.
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Affiliation(s)
- Sara A. Thannickal
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Sophie N. Spector
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Kenneth A. Stapleford
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
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5
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Koch J, Xin Q, Obr M, Schäfer A, Rolfs N, Anagho HA, Kudulyte A, Woltereck L, Kummer S, Campos J, Uckeley ZM, Bell-Sakyi L, Kräusslich HG, Schur FKM, Acuna C, Lozach PY. The phenuivirus Toscana virus makes an atypical use of vacuolar acidity to enter host cells. PLoS Pathog 2023; 19:e1011562. [PMID: 37578957 PMCID: PMC10449198 DOI: 10.1371/journal.ppat.1011562] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 08/24/2023] [Accepted: 07/17/2023] [Indexed: 08/16/2023] Open
Abstract
Toscana virus is a major cause of arboviral disease in humans in the Mediterranean basin during summer. However, early virus-host cell interactions and entry mechanisms remain poorly characterized. Investigating iPSC-derived human neurons and cell lines, we found that virus binding to the cell surface was specific, and 50% of bound virions were endocytosed within 10 min. Virions entered Rab5a+ early endosomes and, subsequently, Rab7a+ and LAMP-1+ late endosomal compartments. Penetration required intact late endosomes and occurred within 30 min following internalization. Virus entry relied on vacuolar acidification, with an optimal pH for viral membrane fusion at pH 5.5. The pH threshold increased to 5.8 with longer pre-exposure of virions to the slightly acidic pH in early endosomes. Strikingly, the particles remained infectious after entering late endosomes with a pH below the fusion threshold. Overall, our study establishes Toscana virus as a late-penetrating virus and reveals an atypical use of vacuolar acidity by this virus to enter host cells.
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Affiliation(s)
- Jana Koch
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
- Univ. Lyon, INRAE, EPHE, IVPC, Lyon, France
| | - Qilin Xin
- Univ. Lyon, INRAE, EPHE, IVPC, Lyon, France
| | - Martin Obr
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Alicia Schäfer
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Nina Rolfs
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Holda A. Anagho
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Aiste Kudulyte
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Lea Woltereck
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Susann Kummer
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
| | - Joaquin Campos
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Zina M. Uckeley
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Lesley Bell-Sakyi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United-Kingdom
| | - Hans-Georg Kräusslich
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
| | - Florian KM. Schur
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Claudio Acuna
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Pierre-Yves Lozach
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
- Univ. Lyon, INRAE, EPHE, IVPC, Lyon, France
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6
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Snyman J, Snyman LP, Buhler KJ, Villeneuve CA, Leighton PA, Jenkins EJ, Kumar A. California Serogroup Viruses in a Changing Canadian Arctic: A Review. Viruses 2023; 15:1242. [PMID: 37376542 DOI: 10.3390/v15061242] [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: 01/31/2023] [Revised: 04/24/2023] [Accepted: 05/18/2023] [Indexed: 06/29/2023] Open
Abstract
The Arctic is warming at four times the global rate, changing the diversity, activity and distribution of vectors and associated pathogens. While the Arctic is not often considered a hotbed of vector-borne diseases, Jamestown Canyon virus (JCV) and Snowshoe Hare virus (SSHV) are mosquito-borne zoonotic viruses of the California serogroup endemic to the Canadian North. The viruses are maintained by transovarial transmission in vectors and circulate among vertebrate hosts, both of which are not well characterized in Arctic regions. While most human infections are subclinical or mild, serious cases occur, and both JCV and SSHV have recently been identified as leading causes of arbovirus-associated neurological diseases in North America. Consequently, both viruses are currently recognised as neglected and emerging viruses of public health concern. This review aims to summarise previous findings in the region regarding the enzootic transmission cycle of both viruses. We identify key gaps and approaches needed to critically evaluate, detect, and model the effects of climate change on these uniquely northern viruses. Based on limited data, we predict that (1) these northern adapted viruses will increase their range northwards, but not lose range at their southern limits, (2) undergo more rapid amplification and amplified transmission in endemic regions for longer vector-biting seasons, (3) take advantage of northward shifts of hosts and vectors, and (4) increase bite rates following an increase in the availability of breeding sites, along with phenological synchrony between the reproduction cycle of theorized reservoirs (such as caribou calving) and mosquito emergence.
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Affiliation(s)
- Jumari Snyman
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Louwrens P Snyman
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Kayla J Buhler
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Carol-Anne Villeneuve
- Research Group on Epidemiology of Zoonoses and Public Health (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Patrick A Leighton
- Research Group on Epidemiology of Zoonoses and Public Health (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Emily J Jenkins
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Anil Kumar
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
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7
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Thannickal SA, Spector SN, Stapleford KA. The La Crosse virus class II fusion glycoprotein ij loop contributes to infectivity and cholesterol-dependent entry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.22.529620. [PMID: 36865275 PMCID: PMC9980073 DOI: 10.1101/2023.02.22.529620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Arthropod-borne viruses (arboviruses) are an emerging and evolving global public health threat with little to no antiviral treatments. La Crosse virus (LACV) from the Bunyavirales order is responsible for pediatric encephalitis cases in the United States, yet little is known about the infectivity of LACV. Given the structural similarities between class II fusion glycoproteins of LACV and chikungunya virus (CHIKV), an alphavirus from the Togaviridae family, we hypothesized that LACV would share similar entry mechanisms to CHIKV. To test this hypothesis, we performed cholesterol-depletion and repletion assays and used cholesterol modulating compounds to study LACV entry and replication. We found that LACV entry was cholesterol-dependent while replication was less affected by cholesterol manipulation. In addition, we generated single point mutants in the LACV ij loop that corresponded to known CHIKV residues important for virus entry. We found that a conserved histidine and alanine residue in the Gc ij loop impaired virus infectivity and attenuate LACV in vitro and in vivo . Finally, we took an evolution-based approach to explore how the LACV glycoprotein evolution in mosquitoes and mice. We found multiple variants that cluster in the Gc glycoprotein head domain, supporting the Gc glycoprotein as a target for LACV adaptation. Together, these results begin to characterize the mechanisms of LACV infectivity and how the LACV glycoprotein contributes to infectivity and pathogenesis. Importance Vector-borne arboviruses are significant health threats leading to devastating disease worldwide. This emergence and the fact that there are little to no vaccines or antivirals targeting these viruses highlights the need to study how arboviruses replicate at the molecular level. One potential antiviral target is the class II fusion glycoprotein. Alphaviruses, flaviviruses, and bunyaviruses encode a class II fusion glycoprotein that contain strong structural similarities in the tip of domain II. Here we show that the bunyavirus La Crosse virus uses similar mechanisms to entry as the alphavirus chikungunya virus and residues in the ij loop are important for virus infectivity. These studies show that genetically diverse viruses use similar mechanisms through concerned structure domains, suggesting these may be a target for broad-spectrum antivirals to multiple arbovirus families.
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8
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Hellert J, Aebischer A, Haouz A, Guardado-Calvo P, Reiche S, Beer M, Rey FA. Structure, function, and evolution of the Orthobunyavirus membrane fusion glycoprotein. Cell Rep 2023; 42:112142. [PMID: 36827185 DOI: 10.1016/j.celrep.2023.112142] [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: 10/22/2022] [Revised: 12/29/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
La Crosse virus, responsible for pediatric encephalitis in the United States, and Schmallenberg virus, a highly teratogenic veterinary virus in Europe, belong to the large Orthobunyavirus genus of zoonotic arthropod-borne pathogens distributed worldwide. Viruses in this under-studied genus cause CNS infections or fever with debilitating arthralgia/myalgia syndromes, with no effective treatment. The main surface antigen, glycoprotein Gc (∼1,000 residues), has a variable N-terminal half (GcS) targeted by the patients' antibody response and a conserved C-terminal moiety (GcF) responsible for membrane fusion during cell entry. Here, we report the X-ray structure of post-fusion La Crosse and Schmallenberg virus GcF, revealing the molecular determinants for hairpin formation and trimerization required to drive membrane fusion. We further experimentally confirm the role of residues in the fusion loops and in a vestigial endoplasmic reticulum (ER) translocation sequence at the GcS-GcF junction. The resulting knowledge provides essential molecular underpinnings for future development of potential therapeutic treatments and vaccines.
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Affiliation(s)
- Jan Hellert
- Structural Virology Unit, Institut Pasteur - Université Paris-Cité, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015 Paris, France; Centre for Structural Systems Biology (CSSB), Leibniz-Institut für Virologie (LIV), Notkestraße 85, 22607 Hamburg, Germany
| | - Andrea Aebischer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany; Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany
| | - Ahmed Haouz
- Crystallography Platform C2RT, Institut Pasteur, CNRS UMR 3528, 25-28 rue du Dr. Roux, 75015 Paris, France
| | - Pablo Guardado-Calvo
- Structural Virology Unit, Institut Pasteur - Université Paris-Cité, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015 Paris, France
| | - Sven Reiche
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany.
| | - Félix A Rey
- Structural Virology Unit, Institut Pasteur - Université Paris-Cité, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015 Paris, France.
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9
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Foster JE, López K, Eastwood G, Guzman H, Carrington CVF, Tesh RB, Auguste AJ. Phylogenetic characterization of Orthobunyaviruses isolated from Trinidad shows evidence of natural reassortment. Virus Genes 2023; 59:473-478. [PMID: 36763228 DOI: 10.1007/s11262-023-01973-5] [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: 10/18/2022] [Accepted: 01/29/2023] [Indexed: 02/11/2023]
Abstract
The genus Orthobunyavirus is a diverse group of viruses in the family Peribunyaviridae, recently classified into 20 serogroups, and 103 virus species. Although most viruses within these serogroups are phylogenetically distinct, the absence of complete genome sequences has left several viruses incompletely characterized. Here we report the complete genome sequences for 11 orthobunyaviruses isolated from Trinidad, French Guiana, Guatemala, and Panama that were serologically classified into six serogroups and 10 species. Phylogenetic analyses of these 11 newly derived sequences indicate that viruses belonging to the Patois, Capim, Guama, and Group C serocomplexes all have a close genetic origin. We show that three of the 11 orthobunyaviruses characterized (belonging to the Group C and Bunyamwera serogroups) have evidence of histories of natural reassortment through the M genome segment. Our data also suggests that two distinct lineages of Group C viruses concurrently circulate in Trinidad and are transmitted by the same mosquito vectors. This study also highlights the importance of complementing serological identification with nucleotide sequencing when characterizing orthobunyaviruses.
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Affiliation(s)
- Jerome E Foster
- Department of Preclinical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago
| | - Krisangel López
- Department of Entomology, College of Agriculture and Life Sciences, Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Gillian Eastwood
- Department of Entomology, College of Agriculture and Life Sciences, Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.,Center for Emerging, Zoonotic, and Arthropod-Borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.,Global Change Center at Virginia Tech, Blacksburg, VA, 24061, USA
| | - Hilda Guzman
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Christine V F Carrington
- Department of Preclinical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago
| | - Robert B Tesh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Albert J Auguste
- Department of Entomology, College of Agriculture and Life Sciences, Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA. .,Center for Emerging, Zoonotic, and Arthropod-Borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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10
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Windhaber S, Xin Q, Uckeley ZM, Koch J, Obr M, Garnier C, Luengo-Guyonnot C, Duboeuf M, Schur FKM, Lozach PY. The Orthobunyavirus Germiston Enters Host Cells from Late Endosomes. J Virol 2022; 96:e0214621. [PMID: 35019710 PMCID: PMC8906410 DOI: 10.1128/jvi.02146-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/03/2022] [Indexed: 01/01/2023] Open
Abstract
With more than 80 members worldwide, the Orthobunyavirus genus in the Peribunyaviridae family is a large genus of enveloped RNA viruses, many of which are emerging pathogens in humans and livestock. How orthobunyaviruses (OBVs) penetrate and infect mammalian host cells remains poorly characterized. Here, we investigated the entry mechanisms of the OBV Germiston (GERV). Viral particles were visualized by cryo-electron microscopy and appeared roughly spherical with an average diameter of 98 nm. Labeling of the virus with fluorescent dyes did not adversely affect its infectivity and allowed the monitoring of single particles in fixed and live cells. Using this approach, we found that endocytic internalization of bound viruses was asynchronous and occurred within 30 to 40 min. The virus entered Rab5a-positive (Rab5a+) early endosomes and, subsequently, late endosomal vacuoles containing Rab7a but not LAMP-1. Infectious entry did not require proteolytic cleavage, and endosomal acidification was sufficient and necessary for viral fusion. Acid-activated penetration began 15 to 25 min after initiation of virus internalization and relied on maturation of early endosomes to late endosomes. The optimal pH for viral membrane fusion was slightly below 6.0, and penetration was hampered when the potassium influx was abolished. Overall, our study provides real-time visualization of GERV entry into host cells and demonstrates the importance of late endosomal maturation in facilitating OBV penetration. IMPORTANCE Orthobunyaviruses (OBVs), which include La Crosse, Oropouche, and Schmallenberg viruses, represent a growing threat to humans and domestic animals worldwide. Ideally, preventing OBV spread requires approaches that target early stages of infection, i.e., virus entry. However, little is known about the molecular and cellular mechanisms by which OBVs enter and infect host cells. Here, we developed accurate, sensitive tools and assays to investigate the penetration process of GERV. Our data emphasize the central role of late endosomal maturation in GERV entry, providing a comprehensive overview of the early stages of an OBV infection. Our study also brings a complete toolbox of innovative methods to study each step of the OBV entry program in fixed and living cells, from virus binding and endocytosis to fusion and penetration. The information gained herein lays the foundation for the development of antiviral strategies aiming to block OBV entry.
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Affiliation(s)
- Stefan Windhaber
- CellNetworks-Cluster of Excellence Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Qilin Xin
- University of Lyon, INRAE, EPHE, IVPC, Lyon, France
| | - Zina M. Uckeley
- CellNetworks-Cluster of Excellence Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Jana Koch
- CellNetworks-Cluster of Excellence Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Martin Obr
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | | | | | | | - Pierre-Yves Lozach
- CellNetworks-Cluster of Excellence Heidelberg, Germany
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
- University of Lyon, INRAE, EPHE, IVPC, Lyon, France
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Databases, Knowledgebases, and Software Tools for Virus Informatics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1368:1-19. [DOI: 10.1007/978-981-16-8969-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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