1
|
Furuyama W, Yamada K, Sakaguchi M, Marzi A, Nanbo A. Marburg virus exploits the Rab11-mediated endocytic pathway in viral-particle production. Microbiol Spectr 2024; 12:e0026924. [PMID: 39078193 PMCID: PMC11370620 DOI: 10.1128/spectrum.00269-24] [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: 03/12/2024] [Accepted: 06/10/2024] [Indexed: 07/31/2024] Open
Abstract
Filoviruses produce viral particles with characteristic filamentous morphology. The major viral matrix protein, VP40, is trafficked to the plasma membrane and promotes viral particle formation and subsequent viral egress. In the present study, we assessed the role of the small GTPase Rab11-mediated endocytic pathway in Marburg virus (MARV) particle formation and budding. Although Rab11 was predominantly localized in the perinuclear region, it exhibited a more diffuse distribution in the cytoplasm of cells transiently expressing MARV VP40. Rab11 was incorporated into MARV-like particles. Expression of the dominant-negative form of Rab11 and knockdown of Rab11 decreased the amount of VP40 fractions in the cell periphery. Moreover, downregulation of Rab11 moderately reduced the release of MARV-like particles and authentic MARV. We further demonstrated that VP40 induces the distribution of the microtubule network toward the cell periphery, which was partly associated with Rab11. Depolymerization of microtubules reduced the accumulation of VP40 in the cell periphery along with viral particle formation. VP40 physically interacted with α-tubulin, a major component of microtubules, but not with Rab11. Taken together, these results suggested that VP40 partly interacts with microtubules and facilitates their distribution toward the cell periphery, leading to the trafficking of transiently tethering Rab11-positive vesicles toward the cell surface. As we previously demonstrated the role of Rab11 in the formation of Ebola virus particles, the results here suggest that filoviruses in general exploit the vesicle-trafficking machinery for proper virus-particle formation and subsequent egress. These pathways may be a potential target for the development of pan-filovirus therapeutics.IMPORTANCEFiloviruses, including Marburg and Ebola viruses, produce distinct filamentous viral particles. Although it is well known that the major viral matrix protein of these viruses, VP40, is trafficked to the cell surface and promotes viral particle production, details regarding the associated molecular mechanisms remain unclear. To address this knowledge gap, we investigated the role of the small GTPase Rab11-mediated endocytic pathway in this process. Our findings revealed that Marburg virus exploits the Rab11-mediated vesicle-trafficking pathway for the release of virus-like particles and authentic virions in a microtubule network-dependent manner. Previous findings demonstrated that Rab11 is also involved in Ebola virus-particle production. Taken together, these data suggest that filoviruses, in general, may hijack the microtubule-dependent vesicle-trafficking machinery for productive replication. Therefore, this pathway presents as a potential target for the development of pan-filovirus therapeutics.
Collapse
Affiliation(s)
- Wakako Furuyama
- National Research Center for the Control and Prevention of Infectious Diseases, Nagasaki University, Nagasaki, Japan
| | - Kento Yamada
- National Research Center for the Control and Prevention of Infectious Diseases, Nagasaki University, Nagasaki, Japan
| | - Miako Sakaguchi
- Central Laboratory, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Andrea Marzi
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Asuka Nanbo
- National Research Center for the Control and Prevention of Infectious Diseases, Nagasaki University, Nagasaki, Japan
| |
Collapse
|
2
|
Bodmer BS, Hoenen T, Wendt L. Molecular insights into the Ebola virus life cycle. Nat Microbiol 2024; 9:1417-1426. [PMID: 38783022 DOI: 10.1038/s41564-024-01703-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Ebola virus and other orthoebolaviruses cause severe haemorrhagic fevers in humans, with very high case fatality rates. Their non-segmented single-stranded RNA genome encodes only seven structural proteins and a small number of non-structural proteins to facilitate the virus life cycle. The basics of this life cycle are well established, but recent advances have substantially increased our understanding of its molecular details, including the viral and host factors involved. Here we provide a comprehensive overview of our current knowledge of the molecular details of the orthoebolavirus life cycle, with a special focus on proviral host factors. We discuss the multistep entry process, viral RNA synthesis in specialized phase-separated intracellular compartments called inclusion bodies, the expression of viral proteins and ultimately the assembly of new virus particles and their release at the cell surface. In doing so, we integrate recent studies into the increasingly detailed model that has developed for these fundamental aspects of orthoebolavirus biology.
Collapse
Affiliation(s)
- Bianca S Bodmer
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - Thomas Hoenen
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany.
| | - Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| |
Collapse
|
3
|
Debroy B, Chowdhury S, Pal K. Designing a novel and combinatorial multi-antigenic epitope-based vaccine "MarVax" against Marburg virus-a reverse vaccinology and immunoinformatics approach. J Genet Eng Biotechnol 2023; 21:143. [PMID: 38012426 PMCID: PMC10681968 DOI: 10.1186/s43141-023-00575-w] [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: 05/20/2023] [Accepted: 10/26/2023] [Indexed: 11/29/2023]
Abstract
CONTEXT Marburg virus (MARV) is a member of the Filoviridae family and causes Marburg virus disease (MVD) among humans and primates. With fatality rates going up to 88%, there is currently no commercialized cure or vaccine to combat the infection. The National Institute of Allergy and Infectious Diseases (NIAID) classified MARV as priority pathogen A, which presages the need for a vaccine candidate which can provide stable, long-term adaptive immunity. The surface glycoprotein (GP) and fusion protein (FP) mediate the adherence, fusion, and entry of the virus into the host cell via the TIM-I receptor. Being important antigenic determinants, studies reveal that GP and FP are prone to evolutionary mutations, underscoring the requirement of a vaccine construct capable of eliciting a robust and sustained immune response. In this computational study, a reverse vaccinology approach was employed to design a combinatorial vaccine from conserved and antigenic epitopes of essential viral proteins of MARV, namely GP, VP24, VP30, VP35, and VP40 along with an endogenous protein large polymerase (L). METHODS Epitopes for T-cell and B-cell were predicted using TepiTool and ElliPro, respectively. The surface-exposed TLRs like TLR2, TLR4, and TLR5 were used to screen high-binding affinity epitopes using the protein-peptide docking platform MdockPeP. The best binding epitopes were selected and assembled with linkers to design a recombinant multi-epitope vaccine construct which was then modeled in Robetta. The in silico biophysical and biochemical analyses of the recombinant vaccine were performed. The docking and MD simulation of the vaccine using WebGro and CABS-Flex against TLRs support the stable binding of vaccine candidates. A virtual immune simulation to check the immediate and long-term immunogenicity was carried out using the C-ImmSim server. RESULTS The biochemical characteristics and docking studies with MD simulation establish the recombinant protein vaccine construct MarVax as a stable, antigenic, and potent vaccine molecule. Immune simulation studies reveal 1-year passive immunity which needs to be validated by in vivo studies.
Collapse
Affiliation(s)
- Bishal Debroy
- Department of Biological Sciences, School of Life Science and Biotechnology, Adamas University, Barasat-Barrackpore Road, Kolkata, West Bengal, 700126, India
| | - Sribas Chowdhury
- Department of Biotechnology, School of Life Science and Biotechnology, Adamas University, Barasat-Barrackpore Road, Kolkata, West Bengal, 700126, India
| | - Kuntal Pal
- Cancer Biology Laboratory, Adamas University, Barasat-Barrackpore Road, Kolkata, West Bengal, 700126, India.
- School of Biosciences and Technology (SBST), Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
| |
Collapse
|
4
|
Srivastava S, Sharma D, Kumar S, Sharma A, Rijal R, Asija A, Adhikari S, Rustagi S, Sah S, Al-qaim ZH, Bashyal P, Mohanty A, Barboza JJ, Rodriguez-Morales AJ, Sah R. Emergence of Marburg virus: a global perspective on fatal outbreaks and clinical challenges. Front Microbiol 2023; 14:1239079. [PMID: 37771708 PMCID: PMC10526840 DOI: 10.3389/fmicb.2023.1239079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/25/2023] [Indexed: 09/30/2023] Open
Abstract
The Marburg virus (MV), identified in 1967, has caused deadly outbreaks worldwide, the mortality rate of Marburg virus disease (MVD) varies depending on the outbreak and virus strain, but the average case fatality rate is around 50%. However, case fatality rates have varied from 24 to 88% in past outbreaks depending on virus strain and case management. Designated a priority pathogen by the National Institute of Allergy and Infectious Diseases (NIAID), MV induces hemorrhagic fever, organ failure, and coagulation issues in both humans and non-human primates. This review presents an extensive exploration of MVD outbreak evolution, virus structure, and genome, as well as the sources and transmission routes of MV, including human-to-human spread and involvement of natural hosts such as the Egyptian fruit bat (Rousettus aegyptiacus) and other Chiroptera species. The disease progression involves early viral replication impacting immune cells like monocytes, macrophages, and dendritic cells, followed by damage to the spleen, liver, and secondary lymphoid organs. Subsequent spread occurs to hepatocytes, endothelial cells, fibroblasts, and epithelial cells. MV can evade host immune response by inhibiting interferon type I (IFN-1) synthesis. This comprehensive investigation aims to enhance understanding of pathophysiology, cellular tropism, and injury sites in the host, aiding insights into MVD causes. Clinical data and treatments are discussed, albeit current methods to halt MVD outbreaks remain elusive. By elucidating MV infection's history and mechanisms, this review seeks to advance MV disease treatment, drug development, and vaccine creation. The World Health Organization (WHO) considers MV a high-concern filovirus causing severe and fatal hemorrhagic fever, with a death rate ranging from 24 to 88%. The virus often spreads through contact with infected individuals, originating from animals. Visitors to bat habitats like caves or mines face higher risk. We tailored this search strategy for four databases: Scopus, Web of Science, Google Scholar, and PubMed. we primarily utilized search terms such as "Marburg virus," "Epidemiology," "Vaccine," "Outbreak," and "Transmission." To enhance comprehension of the virus and associated disease, this summary offers a comprehensive overview of MV outbreaks, pathophysiology, and management strategies. Continued research and learning hold promise for preventing and controlling future MVD outbreaks. GRAPHICAL ABSTRACT.
Collapse
Affiliation(s)
- Shriyansh Srivastava
- Department of Pharmacology, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, India
| | - Deepika Sharma
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, India
| | - Sachin Kumar
- Department of Pharmacology, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India
| | - Aditya Sharma
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, India
| | - Rishikesh Rijal
- Division of Infectious Diseases, University of Louisville, Louisville, KY, United States
| | - Ankush Asija
- WVU United Hospital Center, Bridgeport, WV, United States
| | | | - Sarvesh Rustagi
- School of Applied and Life Sciences, Uttaranchal University, Dehradun, Uttarakhand, India
| | - Sanjit Sah
- Global Consortium for Public Health and Research, Datta Meghe Institute of Higher Education and Research, Jawaharlal Nehru Medical College, Wardha, India
- Department of Anesthesia Techniques, SR Sanjeevani Hospital, Siraha, Nepal
| | | | - Prashant Bashyal
- Lumbini Medical College and Teaching Hospital, Kathmandu University Parvas, Palpa, Nepal
| | - Aroop Mohanty
- Department of Clinical Microbiology, All India Institute of Medical Sciences, Gorakhpur, Uttar Pradesh, India
| | | | - Alfonso J. Rodriguez-Morales
- Master Program on Clinical Epidemiology and Biostatistics, Universidad Científica del Sur, Lima, Peru
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut, Lebanon
| | - Ranjit Sah
- Department of Microbiology, Tribhuvan University Teaching Spital, Institute of Medicine, Kathmandu, Nepal
- Department of Microbiology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra, India
- Department of Public Health Dentistry, Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra, India
| |
Collapse
|
5
|
Abir MH, Rahman T, Das A, Etu SN, Nafiz IH, Rakib A, Mitra S, Emran TB, Dhama K, Islam A, Siyadatpanah A, Mahmud S, Kim B, Hassan MM. Pathogenicity and virulence of Marburg virus. Virulence 2022; 13:609-633. [PMID: 35363588 PMCID: PMC8986239 DOI: 10.1080/21505594.2022.2054760] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/10/2022] [Accepted: 03/13/2022] [Indexed: 12/25/2022] Open
Abstract
Marburg virus (MARV) has been a major concern since 1967, with two major outbreaks occurring in 1998 and 2004. Infection from MARV results in severe hemorrhagic fever, causing organ dysfunction and death. Exposure to fruit bats in caves and mines, and human-to-human transmission had major roles in the amplification of MARV outbreaks in African countries. The high fatality rate of up to 90% demands the broad study of MARV diseases (MVD) that correspond with MARV infection. Since large outbreaks are rare for MARV, clinical investigations are often inadequate for providing the substantial data necessary to determine the treatment of MARV disease. Therefore, an overall review may contribute to minimizing the limitations associated with future medical research and improve the clinical management of MVD. In this review, we sought to analyze and amalgamate significant information regarding MARV disease epidemics, pathophysiology, and management approaches to provide a better understanding of this deadly virus and the associated infection.
Collapse
Affiliation(s)
- Mehedy Hasan Abir
- Faculty of Food Science and Technology, Chattogram Veterinary and Animal Sciences University, Chittagong, Bangladesh
| | - Tanjilur Rahman
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Ayan Das
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Silvia Naznin Etu
- Department of Genetic Engineering and Biotechnology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Iqbal Hossain Nafiz
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Ahmed Rakib
- Department of Pharmacy, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Saikat Mitra
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka, Bangladesh
| | - Talha Bin Emran
- Department of Pharmacy, BGC Trust University Bangladesh, Chittagong, Bangladesh
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Ariful Islam
- EcoHealth Alliance, New York, NY, USA
- Centre for Integrative Ecology, School of Life and Environmental Science, Deakin University, Victoria, Australia
| | - Abolghasem Siyadatpanah
- Ferdows School of Paramedical and Health, Birjand University of Medical Sciences, Birjand, Iran
| | - Shafi Mahmud
- Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi, Bangladesh
| | - Bonlgee Kim
- Department of Pathology, College of Korean Medicine, Kyung Hee University, Seoul, Korea
| | - Mohammad Mahmudul Hassan
- Queensland Alliance for One Health Sciences, School of Veterinary Sciences, The University of Queensland, Gatton, Australia
- Department of Physiology, Biochemistry and Pharmacology, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram, Bangladesh
| |
Collapse
|
6
|
Abstract
Ebola virus (EBOV) VP30 regulates viral genome transcription and replication by switching its phosphorylation status. However, the importance of VP30 phosphorylation and dephosphorylation in other viral replication processes such as nucleocapsid and virion assembly is unclear. Interestingly, VP30 is predominantly dephosphorylated by cellular phosphatases in viral inclusions, while it is phosphorylated in the released virions. Thus, uncertainties regarding how VP30 phosphorylation in nucleocapsids is achieved and whether VP30 phosphorylation provides any advantages in later steps in viral replication have arisen. In the present study, to characterize the roles of VP30 phosphorylation in nucleocapsid formation, we used electron microscopic analyses and live cell imaging systems. We identified VP30 localized to the surface of protrusions surrounding nucleoprotein (NP)-forming helical structures in the nucleocapsid, suggesting the involvement in assembly and transport of nucleocapsids. Interestingly, VP30 phosphorylation facilitated its association with nucleocapsid-like structures (NCLSs). On the contrary, VP30 phosphorylation does not influence the transport characteristics and NCLS number leaving from and coming back into viral inclusions, indicating that the phosphorylation status of VP30 is not a prerequisite for NCLS departure. Moreover, the phosphorylation status of VP30 did not cause major differences in nucleocapsid transport in authentic EBOV-infected cells. In the following budding step, the association of VP30 and its phosphorylation status did not influence the budding efficiency of virus-like particles. Taken together, it is plausible that EBOV may utilize the phosphorylation of VP30 for its selective association with nucleocapsids, without affecting nucleocapsid transport and virion budding processes. IMPORTANCE Ebola virus (EBOV) causes severe fevers with unusually high case fatality rates. The nucleocapsid provides the template for viral genome transcription and replication. Thus, understanding the regulatory mechanism behind its formation is important for the development of novel therapeutic approaches. Previously, we established a live-cell imaging system based on the ectopic expression of viral fluorescent fusion proteins, allowing the visualization and characterization of intracytoplasmic transport of nucleocapsid-like structures. EBOV VP30 is an essential transcriptional factor for viral genome synthesis, and, although its role in viral genome transcription and replication is well understood, the functional importance of VP30 phosphorylation in assembly of nucleocapsids is still unclear. Our work determines the localization of VP30 at the surface of ruffled nucleocapsids, which differs from the localization of polymerase in EBOV-infected cells. This study sheds light on the novel role of VP30 phosphorylation in nucleocapsid assembly, which is an important prerequisite for virion formation.
Collapse
|
7
|
Husby ML, Stahelin RV. Negative-sense RNA viruses: An underexplored platform for examining virus-host lipid interactions. Mol Biol Cell 2021; 32:pe1. [PMID: 34570653 PMCID: PMC8684762 DOI: 10.1091/mbc.e19-09-0490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 07/20/2021] [Accepted: 07/30/2021] [Indexed: 11/11/2022] Open
Abstract
Viruses are pathogenic agents that can infect all varieties of organisms, including plants, animals, and humans. These microscopic particles are genetically simple as they encode a limited number of proteins that undertake a wide range of functions. While structurally distinct, viruses often share common characteristics that have evolved to aid in their infectious life cycles. A commonly underappreciated characteristic of many deadly viruses is a lipid envelope that surrounds their protein and genetic contents. Notably, the lipid envelope is formed from the host cell the virus infects. Lipid-enveloped viruses comprise a diverse range of pathogenic viruses, which often lead to high fatality rates and many lack effective therapeutics and/or vaccines. This perspective primarily focuses on the negative-sense RNA viruses from the order Mononegavirales, which obtain their lipid envelope from the host plasma membrane. Specifically, the perspective highlights the common themes of host cell lipid and membrane biology necessary for virus replication, assembly, and budding.
Collapse
Affiliation(s)
- Monica L. Husby
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907
| | - Robert V. Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907
| |
Collapse
|
8
|
Amiar S, Husby ML, Wijesinghe KJ, Angel S, Bhattarai N, Gerstman BS, Chapagain PP, Li S, Stahelin RV. Lipid-specific oligomerization of the Marburg virus matrix protein VP40 is regulated by two distinct interfaces for virion assembly. J Biol Chem 2021; 296:100796. [PMID: 34019871 PMCID: PMC8191294 DOI: 10.1016/j.jbc.2021.100796] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 02/03/2023] Open
Abstract
Marburg virus (MARV) is a lipid-enveloped virus harboring a negative-sense RNA genome, which has caused sporadic outbreaks of viral hemorrhagic fever in sub-Saharan Africa. MARV assembles and buds from the host cell plasma membrane where MARV matrix protein (mVP40) dimers associate with anionic lipids at the plasma membrane inner leaflet and undergo a dynamic and extensive self-oligomerization into the structural matrix layer. The MARV matrix layer confers the virion filamentous shape and stability but how host lipids modulate mVP40 oligomerization is mostly unknown. Using in vitro and cellular techniques, we present a mVP40 assembly model highlighting two distinct oligomerization interfaces: the (N-terminal domain [NTD] and C-terminal domain [CTD]) in mVP40. Cellular studies of NTD and CTD oligomerization interface mutants demonstrate the importance of each interface in matrix assembly. The assembly steps include protein trafficking to the plasma membrane, homo-multimerization that induced protein enrichment, plasma membrane fluidity changes, and elongations at the plasma membrane. An ascorbate peroxidase derivative (APEX)-transmission electron microscopy method was employed to closely assess the ultrastructural localization and formation of viral particles for wildtype mVP40 and NTD and CTD oligomerization interface mutants. Taken together, these studies present a mechanistic model of mVP40 oligomerization and assembly at the plasma membrane during virion assembly that requires interactions with phosphatidylserine for NTD–NTD interactions and phosphatidylinositol-4,5-bisphosphate for proper CTD–CTD interactions. These findings have broader implications in understanding budding of lipid-enveloped viruses from the host cell plasma membrane and potential strategies to target protein–protein or lipid–protein interactions to inhibit virus budding.
Collapse
Affiliation(s)
- Souad Amiar
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Monica L Husby
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Kaveesha J Wijesinghe
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Stephanie Angel
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, Florida, USA
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, Florida, USA; Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, Florida, USA; Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA
| | - Sheng Li
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Robert V Stahelin
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA.
| |
Collapse
|
9
|
Impact of Měnglà Virus Proteins on Human and Bat Innate Immune Pathways. J Virol 2020; 94:JVI.00191-20. [PMID: 32295912 DOI: 10.1128/jvi.00191-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/07/2020] [Indexed: 12/31/2022] Open
Abstract
Měnglà virus (MLAV), identified in Rousettus bats, is a phylogenetically distinct member of the family Filoviridae Because the filoviruses Ebola virus (EBOV) and Marburg virus (MARV) modulate host innate immunity, MLAV VP35, VP40, and VP24 proteins were compared with their EBOV and MARV homologs for innate immune pathway modulation. In human and Rousettus cells, MLAV VP35 behaved like EBOV and MARV VP35s, inhibiting virus-induced activation of the interferon beta (IFN-β) promoter and interferon regulatory factor 3 (IRF3) phosphorylation. MLAV VP35 also interacted with PACT, a host protein engaged by EBOV VP35 to inhibit RIG-I signaling. MLAV VP35 also inhibits PKR activation. MLAV VP40 was demonstrated to inhibit type I IFN-induced gene expression in human and bat cells. It blocked STAT1 tyrosine phosphorylation induced either by type I IFN or overexpressed Jak1, paralleling MARV VP40. MLAV VP40 also inhibited virus-induced IFN-β promoter activation, a property shared by MARV VP40 and EBOV VP24. A Jak kinase inhibitor did not recapitulate this inhibition in the absence of viral proteins. Therefore, inhibition of Jak-STAT signaling is insufficient to explain inhibition of IFN-β promoter activation. MLAV VP24 did not inhibit IFN-induced gene expression or bind karyopherin α proteins, properties of EBOV VP24. MLAV VP24 differed from MARV VP24 in that it failed to interact with Keap1 or activate an antioxidant response element reporter gene due to the absence of a Keap1-binding motif. These functional observations support a closer relationship of MLAV to MARV than to EBOV but also are consistent with MLAV belonging to a distinct genus.IMPORTANCE EBOV and MARV, members of the family Filoviridae, are highly pathogenic zoonotic viruses that cause severe disease in humans. Both viruses use several mechanisms to modulate the host innate immune response, and these likely contribute to the severity of disease. Here, we demonstrate that MLAV, a filovirus newly discovered in a bat, suppresses antiviral type I interferon responses in both human and bat cells. Inhibitory activities are possessed by MLAV VP35 and VP40, which parallels how MARV blocks IFN responses. However, whereas MARV activates cellular antioxidant responses through an interaction between its VP24 protein and host protein Keap1, MLAV VP24 lacks a Keap1-binding motif and fails to activate this cytoprotective response. These data indicate that MLAV possesses immune-suppressing functions that could facilitate human infection. They also support the placement of MLAV in a different genus than either EBOV or MARV.
Collapse
|
10
|
Wijesinghe KJ, McVeigh L, Husby ML, Bhattarai N, Ma J, Gerstman BS, Chapagain PP, Stahelin RV. Mutation of Hydrophobic Residues in the C-Terminal Domain of the Marburg Virus Matrix Protein VP40 Disrupts Trafficking to the Plasma Membrane. Viruses 2020; 12:v12040482. [PMID: 32344654 PMCID: PMC7232359 DOI: 10.3390/v12040482] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 12/13/2022] Open
Abstract
Marburg virus (MARV) is a lipid-enveloped negative sense single stranded RNA virus, which can cause a deadly hemorrhagic fever. MARV encodes seven proteins, including VP40 (mVP40), a matrix protein that interacts with the cytoplasmic leaflet of the host cell plasma membrane. VP40 traffics to the plasma membrane inner leaflet, where it assembles to facilitate the budding of viral particles. VP40 is a multifunctional protein that interacts with several host proteins and lipids to complete the viral replication cycle, but many of these host interactions remain unknown or are poorly characterized. In this study, we investigated the role of a hydrophobic loop region in the carboxy-terminal domain (CTD) of mVP40 that shares sequence similarity with the CTD of Ebola virus VP40 (eVP40). These conserved hydrophobic residues in eVP40 have been previously shown to be critical to plasma membrane localization and membrane insertion. An array of cellular experiments and confirmatory in vitro work strongly suggests proper orientation and hydrophobic residues (Phe281, Leu283, and Phe286) in the mVP40 CTD are critical to plasma membrane localization. In line with the different functions proposed for eVP40 and mVP40 CTD hydrophobic residues, molecular dynamics simulations demonstrate large flexibility of residues in the EBOV CTD whereas conserved mVP40 hydrophobic residues are more restricted in their flexibility. This study sheds further light on important amino acids and structural features in mVP40 required for its plasma membrane localization as well as differences in the functional role of CTD amino acids in eVP40 and mVP40.
Collapse
Affiliation(s)
- Kaveesha J. Wijesinghe
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.J.W.); (L.M.)
| | - Luke McVeigh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.J.W.); (L.M.)
| | - Monica L. Husby
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA;
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
| | - Jia Ma
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA;
| | - Bernard S. Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- Biomolecules Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- Biomolecules Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V. Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA;
- Correspondence: ; Tel.: +1-765-494-4152
| |
Collapse
|
11
|
The Integrity of the YxxL Motif of Ebola Virus VP24 Is Important for the Transport of Nucleocapsid-Like Structures and for the Regulation of Viral RNA Synthesis. J Virol 2020; 94:JVI.02170-19. [PMID: 32102881 DOI: 10.1128/jvi.02170-19] [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: 01/05/2020] [Accepted: 02/15/2020] [Indexed: 12/15/2022] Open
Abstract
While it is well appreciated that late domains in the viral matrix proteins are crucial to mediate efficient virus budding, little is known about roles of late domains in the viral nucleocapsid proteins. Here, we characterized the functional relevance of a YxxL motif with potential late-domain function in the Ebola virus nucleocapsid protein VP24. Mutations in the YxxL motif had two opposing effects on the functions of VP24. On the one hand, the mutation affected the regulatory function of VP24 in viral RNA transcription and replication, which correlated with an increased incorporation of minigenomes into released transcription- and replication-competent virus-like particles (trVLPs). Consequently, cells infected with those trVLPs showed higher levels of viral transcription. On the other hand, mutations of the YxxL motif greatly impaired the intracellular transport of nucleocapsid-like structures (NCLSs) composed of the viral proteins NP, VP35, and VP24 and the length of released trVLPs. Attempts to rescue recombinant Ebola virus expressing YxxL-deficient VP24 failed, underlining the importance of this motif for the viral life cycle.IMPORTANCE Ebola virus (EBOV) causes a severe fever with high case fatality rates and, so far, no available specific therapy. Understanding the interplay between viral and host proteins is important to identify new therapeutic approaches. VP24 is one of the essential nucleocapsid components and is necessary to regulate viral RNA synthesis and condense viral nucleocapsids before their transport to the plasma membrane. Our functional analyses of the YxxL motif in VP24 suggested that it serves as an interface between nucleocapsid-like structures (NCLSs) and cellular proteins, promoting intracellular transport of NCLSs in an Alix-independent manner. Moreover, the YxxL motif is necessary for the inhibitory function of VP24 in viral RNA synthesis. A failure to rescue EBOV encoding VP24 with a mutated YxxL motif indicated that the integrity of the YxxL motif is essential for EBOV growth. Thus, this motif might represent a potential target for antiviral interference.
Collapse
|
12
|
Takamatsu Y, Dolnik O, Noda T, Becker S. A live-cell imaging system for visualizing the transport of Marburg virus nucleocapsid-like structures. Virol J 2019; 16:159. [PMID: 31856881 PMCID: PMC6923871 DOI: 10.1186/s12985-019-1267-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/05/2019] [Indexed: 01/22/2023] Open
Abstract
Background Live-cell imaging is a powerful tool for visualization of the spatio-temporal dynamics of moving signals in living cells. Although this technique can be utilized to visualize nucleocapsid transport in Marburg virus (MARV)- or Ebola virus-infected cells, the experiments require biosafety level-4 (BSL-4) laboratories, which are restricted to trained and authorized individuals. Methods To overcome this limitation, we developed a live-cell imaging system to visualize MARV nucleocapsid-like structures using fluorescence-conjugated viral proteins, which can be conducted outside BSL-4 laboratories. Results Our experiments revealed that nucleocapsid-like structures have similar transport characteristics to those of nucleocapsids observed in MARV-infected cells, both of which are mediated by actin polymerization. Conclusions We developed a non-infectious live cell imaging system to visualize intracellular transport of MARV nucleocapsid-like structures. This system provides a safe platform to evaluate antiviral drugs that inhibit MARV nucleocapsid transport.
Collapse
Affiliation(s)
- Yuki Takamatsu
- Institute of Virology, Philipps-University Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany.,Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Shogoin-Kawahara-cho 53, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Olga Dolnik
- Institute of Virology, Philipps-University Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Takeshi Noda
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Shogoin-Kawahara-cho 53, Sakyo-ku, Kyoto, 606-8507, Japan. .,Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Shogoin-Kawahara-cho 53, Sakyo-ku, Kyoto, 606-8507, Japan.
| | - Stephan Becker
- Institute of Virology, Philipps-University Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany. .,German Center of Infection Research (DZIF), partner site Giessen-Marburg-Langen, Marburg, Germany.
| |
Collapse
|
13
|
Nanbo A, Ohba Y. Budding of Ebola Virus Particles Requires the Rab11-Dependent Endocytic Recycling Pathway. J Infect Dis 2019; 218:S388-S396. [PMID: 30476249 PMCID: PMC6249604 DOI: 10.1093/infdis/jiy460] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The Ebola virus-encoded major matrix protein VP40 traffics to the plasma membrane, which leads to the formation of filamentous viral particles and subsequent viral egress. However, the cellular machineries underlying this process are not fully understood. In the present study, we have assessed the role of host endocytic recycling in Ebola virus particle formation. We found that a small GTPase Rab11, which regulates recycling of molecules among the trans-Golgi network, recycling endosomes, and the plasma membrane, was incorporated in Ebola virus-like particles. Although Rab11 predominantly localized in the perinuclear region, it distributed diffusely in the cytoplasm and partly localized in the periphery of the cells transiently expressing VP40. In contrast, Rab11 exhibited a perinuclear distribution when 2 VP40 derivatives that lack ability to traffic to the plasma membrane were expressed. Finally, expression of a dominant-negative form of Rab11 or knockdown of Rab11 inhibited both VP40-induced clusters at the plasma membrane and release of viral-like particles. Taken together, our findings demonstrate that Ebola virus exploits host endocytic recycling machinery to facilitate the trafficking of VP40 to the cell surface and the subsequent release of viral-like particles for its establishment of efficient viral egress.
Collapse
Affiliation(s)
- Asuka Nanbo
- Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yusuke Ohba
- Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| |
Collapse
|
14
|
Abstract
This chapter reviews our current knowledge about the spatiotemporal assembly of filoviral particles. We will follow particles from nucleocapsid entry into the cytoplasm until the nucleocapsids are enveloped at the plasma membrane. We will also highlight the currently open scientific questions surrounding filovirus assembly.
Collapse
|
15
|
Pleet ML, Erickson J, DeMarino C, Barclay RA, Cowen M, Lepene B, Liang J, Kuhn JH, Prugar L, Stonier SW, Dye JM, Zhou W, Liotta LA, Aman MJ, Kashanchi F. Ebola Virus VP40 Modulates Cell Cycle and Biogenesis of Extracellular Vesicles. J Infect Dis 2018; 218:S365-S387. [PMID: 30169850 PMCID: PMC6249571 DOI: 10.1093/infdis/jiy472] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background Ebola virus (EBOV) mainly targets myeloid cells; however, extensive death of T cells is often observed in lethal infections. We have previously shown that EBOV VP40 in exosomes causes recipient immune cell death. Methods Using VP40-producing clones, we analyzed donor cell cycle, extracellular vesicle (EV) biogenesis, and recipient immune cell death. Transcription of cyclin D1 and nuclear localization of VP40 were examined via kinase and chromatin immunoprecipitation assays. Extracellular vesicle contents were characterized by mass spectrometry, cytokine array, and western blot. Biosafety level-4 facilities were used for wild-type Ebola virus infection studies. Results VP40 EVs induced apoptosis in recipient T cells and monocytes. VP40 clones were accelerated in growth due to cyclin D1 upregulation, and nuclear VP40 was found bound to the cyclin D1 promoter. Accelerated cell cycling was related to EV biogenesis, resulting in fewer but larger EVs. VP40 EV contents were enriched in ribonucleic acid-binding proteins and cytokines (interleukin-15, transforming growth factor-β1, and interferon-γ). Finally, EBOV-infected cell and animal EVs contained VP40, nucleoprotein, and glycoprotein. Conclusions Nuclear VP40 upregulates cyclin D1 levels, resulting in dysregulated cell cycle and EV biogenesis. Packaging of cytokines and EBOV proteins into EVs from infected cells may be responsible for the decimation of immune cells during EBOV pathogenesis.
Collapse
Affiliation(s)
- Michelle L Pleet
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, Virginia
| | - James Erickson
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, Virginia
| | - Catherine DeMarino
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, Virginia
| | - Robert A Barclay
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, Virginia
| | - Maria Cowen
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, Virginia
| | | | - Janie Liang
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland
| | - Laura Prugar
- Virology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland
| | - Spencer W Stonier
- Virology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland
| | - John M Dye
- Virology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland
| | - Weidong Zhou
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia
| | - Lance A Liotta
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia
| | - M Javad Aman
- Integrated BioTherapeutics, Inc., Gaithersburg, Maryland
| | - Fatah Kashanchi
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, Virginia
| |
Collapse
|
16
|
Filovirus proteins for antiviral drug discovery: Structure/function of proteins involved in assembly and budding. Antiviral Res 2018; 150:183-192. [DOI: 10.1016/j.antiviral.2017.12.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/20/2017] [Accepted: 12/28/2017] [Indexed: 01/30/2023]
|
17
|
Lier C, Becker S, Biedenkopf N. Dynamic phosphorylation of Ebola virus VP30 in NP-induced inclusion bodies. Virology 2017; 512:39-47. [PMID: 28915404 DOI: 10.1016/j.virol.2017.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/18/2017] [Accepted: 09/07/2017] [Indexed: 12/22/2022]
Abstract
Zaire Ebolavirus (EBOV) causes a severe feverish disease with high case fatality rates. Transcription of EBOV is dependent on the activity of the nucleocapsid protein VP30 which represents an essential viral transcription factor. Activity of VP30 is regulated via phosphorylation at six N-terminal serine residues. Recent data demonstrated that dynamic phosphorylation and dephosphorylation of serine residue 29 is essential for transcriptional support activity of VP30. To analyze the spatio/temporal dynamics of VP30 phosphorylation, we generated a peptide antibody recognizing specifically VP30 phosphorylated at serine 29. Using this antibody we could demonstrate that (i) the majority of VP30 molecules in EBOV-infected cells is dephosphorylated at the crucial position serine 29, (ii) both, VP30 phosphorylation and dephosphorylation take place in viral inclusion bodies that are induced by the nucleoprotein NP and (iii) NP influences the phosphorylation state of VP30.
Collapse
Affiliation(s)
- Clemens Lier
- Institute of Virology, Philipps-University Marburg, Marburg, Germany; German Center of Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Philipps-University Marburg, Marburg, Germany; German Center of Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Marburg, Germany.
| | - Nadine Biedenkopf
- Institute of Virology, Philipps-University Marburg, Marburg, Germany; German Center of Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Marburg, Germany.
| |
Collapse
|
18
|
Yu DS, Weng TH, Wu XX, Wang FXC, Lu XY, Wu HB, Wu NP, Li LJ, Yao HP. The lifecycle of the Ebola virus in host cells. Oncotarget 2017; 8:55750-55759. [PMID: 28903457 PMCID: PMC5589696 DOI: 10.18632/oncotarget.18498] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/29/2017] [Indexed: 01/01/2023] Open
Abstract
Ebola haemorrhagic fever causes deadly disease in humans and non-human primates resulting from infection with the Ebola virus (EBOV) genus of the family Filoviridae. However, the mechanisms of EBOV lifecycle in host cells, including viral entry, membrane fusion, RNP formation, GP-tetherin interaction, and VP40-inner leaflet association remain poorly understood. This review describes the biological functions of EBOV proteins and their roles in the lifecycle, summarizes the factors related to EBOV proteins or RNA expression throughout the different phases, and reviews advances with regards to the molecular events and mechanisms of the EBOV lifecycle. Furthermore, the review outlines the aspects remain unclear that urgently need to be solved in future research.
Collapse
Affiliation(s)
- Dong-Shan Yu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Tian-Hao Weng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xiao-Xin Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Frederick X C Wang
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Dallas, TX, USA
| | - Xiang-Yun Lu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Hai-Bo Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Nan-Ping Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Lan-Juan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Hang-Ping Yao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| |
Collapse
|
19
|
Schmidt KM, Mühlberger E. Marburg Virus Reverse Genetics Systems. Viruses 2016; 8:E178. [PMID: 27338448 PMCID: PMC4926198 DOI: 10.3390/v8060178] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 12/16/2022] Open
Abstract
The highly pathogenic Marburg virus (MARV) is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.
Collapse
Affiliation(s)
- Kristina Maria Schmidt
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Novel and Emerging Infectious Diseases, Greifswald-Insel Riems 17493, Germany.
| | - Elke Mühlberger
- Department of Microbiology, School of Medicine, Boston University, 620 Albany Street, Boston, MA 02118, USA.
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
| |
Collapse
|
20
|
Dynamic Phosphorylation of VP30 Is Essential for Ebola Virus Life Cycle. J Virol 2016; 90:4914-4925. [PMID: 26937028 DOI: 10.1128/jvi.03257-15] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/21/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Ebola virus is the causative agent of a severe fever with high fatality rates in humans and nonhuman primates. The regulation of Ebola virus transcription and replication currently is not well understood. An important factor regulating viral transcription is VP30, an Ebola virus-specific transcription factor associated with the viral nucleocapsid. Previous studies revealed that the phosphorylation status of VP30 impacts viral transcription. Together with NP, L, and the polymerase cofactor VP35, nonphosphorylated VP30 supports viral transcription. Upon VP30 phosphorylation, viral transcription ceases. Phosphorylation weakens the interaction between VP30 and the polymerase cofactor VP35 and/or the viral RNA. VP30 thereby is excluded from the viral transcription complex, simultaneously leading to increased viral replication which is supported by NP, L, and VP35 alone. Here, we use an infectious virus-like particle assay and recombinant viruses to show that the dynamic phosphorylation of VP30 is critical for the cotransport of VP30 with nucleocapsids to the sites of viral RNA synthesis, where VP30 is required to initiate primary viral transcription. We further demonstrate that a single serine residue at amino acid position 29 was sufficient to render VP30 active in primary transcription and to generate a recombinant virus with characteristics comparable to those of wild-type virus. In contrast, the rescue of a recombinant virus with a single serine at position 30 in VP30 was unsuccessful. Our results indicate critical roles for phosphorylated and dephosphorylated VP30 during the viral life cycle. IMPORTANCE The current Ebola virus outbreak in West Africa has caused more than 28,000 cases and 11,000 fatalities. Very little is known regarding the molecular mechanisms of how the Ebola virus transcribes and replicates its genome. Previous investigations showed that the transcriptional support activity of VP30 is activated upon VP30 dephosphorylation. The current study reveals that the situation is more complex and that primary transcription as well as the rescue of recombinant Ebola virus also requires the transient phosphorylation of VP30. VP30 encodes six N-proximal serine residues that serve as phosphorylation acceptor sites. The present study shows that the dynamic phosphorylation of serine at position 29 alone is sufficient to activate primary viral transcription. Our results indicate a series of phosphorylation/dephosphorylation events that trigger binding to and release from the nucleocapsid and transcription complex to be essential for the full activity of VP30.
Collapse
|
21
|
The Ebola Virus matrix protein, VP40, requires phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) for extensive oligomerization at the plasma membrane and viral egress. Sci Rep 2016; 6:19125. [PMID: 26753796 PMCID: PMC4709572 DOI: 10.1038/srep19125] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/07/2015] [Indexed: 12/25/2022] Open
Abstract
VP40 is one of eight proteins encoded by the Ebola Virus (EBOV) and serves as the primary matrix protein, forming virus like particles (VLPs) from mammalian cells without the need for other EBOV proteins. While VP40 is required for viral assembly and budding from host cells during infection, the mechanisms that target VP40 to the plasma membrane are not well understood. Phosphatidylserine is required for VP40 plasma membrane binding, VP40 hexamer formation, and VLP egress, However, PS also becomes exposed on the outer membrane leaflet at sites of VP40 budding, raising the question of how VP40 maintains an interaction with the plasma membrane inner leaflet when PS is flipped to the opposite side. To address this question, cellular and in vitro assays were employed to determine if phosphoinositides are important for efficient VP40 localization to the plasma membrane. Cellular studies demonstrated that PI(4,5)P2 was an important component of VP40 assembly at the plasma membrane and subsequent virus like particle formation. Additionally, PI(4,5)P2 was required for formation of extensive oligomers of VP40, suggesting PS and PI(4,5)P2 have different roles in VP40 assembly where PS regulates formation of hexamers from VP40 dimers and PI(4,5)P2 stabilizes and/or induces extensive VP40 oligomerization at the plasma membrane.
Collapse
|
22
|
Crystal Structure of Marburg Virus VP40 Reveals a Broad, Basic Patch for Matrix Assembly and a Requirement of the N-Terminal Domain for Immunosuppression. J Virol 2015; 90:1839-48. [PMID: 26656687 DOI: 10.1128/jvi.01597-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 11/09/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Marburg virus (MARV), a member of the filovirus family, causes severe hemorrhagic fever with up to 90% lethality. MARV matrix protein VP40 is essential for assembly and release of newly copied viruses and also suppresses immune signaling in the infected cell. Here we report the crystal structure of MARV VP40. We found that MARV VP40 forms a dimer in solution, mediated by N-terminal domains, and that formation of this dimer is essential for budding of virus-like particles. We also found the N-terminal domain to be necessary and sufficient for immune antagonism. The C-terminal domains of MARV VP40 are dispensable for immunosuppression but are required for virus assembly. The C-terminal domains are only 16% identical to those of Ebola virus, differ in structure from those of Ebola virus, and form a distinct broad and flat cationic surface that likely interacts with the cell membrane during virus assembly. IMPORTANCE Marburg virus, a cousin of Ebola virus, causes severe hemorrhagic fever, with up to 90% lethality seen in recent outbreaks. Molecular structures and visual images of the proteins of Marburg virus are essential for the development of antiviral drugs. One key protein in the Marburg virus life cycle is VP40, which both assembles the virus and suppresses the immune system. Here we provide the molecular structure of Marburg virus VP40, illustrate differences from VP40 of Ebola virus, and reveal surfaces by which Marburg VP40 assembles progeny and suppresses immune function.
Collapse
|
23
|
A Single Amino Acid Change in the Marburg Virus Matrix Protein VP40 Provides a Replicative Advantage in a Species-Specific Manner. J Virol 2015; 90:1444-54. [PMID: 26581998 DOI: 10.1128/jvi.02670-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 11/12/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Marburg virus (MARV) induces severe hemorrhagic fever in humans and nonhuman primates but only transient nonlethal disease in rodents. However, sequential passages of MARV in rodents boosts infection leading to lethal disease. Guinea pig-adapted MARV contains one mutation in the viral matrix protein VP40 at position 184 (VP40D184N). The contribution of the D184N mutation to the efficacy of replication in a new host is unknown. In the present study, we demonstrated that recombinant MARV containing the D184N mutation in VP40 [rMARVVP40(D184N)] grew to higher titers than wild-type recombinant MARV (rMARVWT) in guinea pig cells. Moreover, rMARVVP40(D184N) displayed higher infectivity in guinea pig cells. Comparative analysis of VP40 functions indicated that neither the interferon (IFN)-antagonistic function nor the membrane binding capabilities of VP40 were affected by the D184N mutation. However, the production of VP40-induced virus-like particles (VLPs) and the recruitment of other viral proteins to the budding site was improved by the D184N mutation in guinea pig cells, which resulted in the higher infectivity of VP40D184N-induced infectious VLPs (iVLPs) compared to that of VP40-induced iVLPs. In addition, the function of VP40 in suppressing viral RNA synthesis was influenced by the D184N mutation specifically in guinea pig cells, thus allowing greater rates of transcription and replication. Our results showed that the improved viral fitness of rMARVVP40(D184N) in guinea pig cells was due to the better viral assembly function of VP40D184N and its lower inhibitory effect on viral transcription and replication rather than modulation of the VP40-mediated suppression of IFN signaling. IMPORTANCE The increased virulence achieved by virus passaging in a new host was accompanied by mutations in the viral genome. Analyzing how these mutations affect the functions of viral proteins and the ability of the virus to grow within new host cells helps in the understanding of the molecular mechanisms increasing virulence. Using a reverse genetics approach, we demonstrated that a single mutation in MARV VP40 detected in a guinea pig-adapted MARV provided a replicative advantage of rMARVVP40(D184N) in guinea pig cells. Our studies show that this replicative advantage of rMARV VP40D184N was based on the improved functions of VP40 in iVLP assembly and in the regulation of transcription and replication rather than on the ability of VP40 to combat the host innate immunity.
Collapse
|
24
|
Dolnik O, Stevermann L, Kolesnikova L, Becker S. Marburg virus inclusions: A virus-induced microcompartment and interface to multivesicular bodies and the late endosomal compartment. Eur J Cell Biol 2015; 94:323-31. [PMID: 26070789 DOI: 10.1016/j.ejcb.2015.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Filovirus infection of target cells leads to the formation of virally induced cytoplasmic inclusions that contain viral nucleocapsids at different stages of maturation. While the role of the inclusions has been unclear since the identification of Marburg and Ebola viruses, it recently became clear that the inclusions are the sites of viral replication, nucleocapsid formation and maturation. Live cell imaging analyses revealed that mature nucleocapsids are transported from inclusions to the filopodia, which represent the major budding sites. Moreover, inclusions recruit cellular proteins that have been shown to support the transport of nucleocapsids. For example, the tumor susceptibility gene 101 protein (Tsg101) interacts with a late domain motif in the nucleocapsid protein NP and recruits the actin-nucleation factor IQGAP1. Complexes of nucleocapsids together with Tsg101 and IQGAP1 are then co-transported along actin filaments. We detected additional proteins (Alix, Nedd4 and the AAA-type ATPase VPS4) of the endosomal sorting complex required for transport (ESCRT) that are recruited into inclusions. Together, the results suggest that nucleocapsids recruit the machinery that enhances viral budding at the plasma membrane. Furthermore, we identified Lamp1 as a marker of the late endosomal compartment in inclusions, while ER, Golgi, TGN and early endosomal markers were absent. In addition, we observed that LC3, a marker of autophagosomal membranes, was present in inclusions. The 3D structures of inclusions show an intricate structure that seems to accommodate an intimate cooperation between cellular and viral components with the intention to support viral transport and budding.
Collapse
Affiliation(s)
- Olga Dolnik
- Institut für Virologie, Philipps Universität Marburg, 35043 Marburg, Germany
| | - Lea Stevermann
- Institut für Virologie, Philipps Universität Marburg, 35043 Marburg, Germany
| | - Larissa Kolesnikova
- Institut für Virologie, Philipps Universität Marburg, 35043 Marburg, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps Universität Marburg, 35043 Marburg, Germany.
| |
Collapse
|
25
|
Dolnik O, Kolesnikova L, Welsch S, Strecker T, Schudt G, Becker S. Interaction with Tsg101 is necessary for the efficient transport and release of nucleocapsids in marburg virus-infected cells. PLoS Pathog 2014; 10:e1004463. [PMID: 25330247 PMCID: PMC4199773 DOI: 10.1371/journal.ppat.1004463] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 09/11/2014] [Indexed: 11/18/2022] Open
Abstract
Endosomal sorting complex required for transport (ESCRT) machinery supports the efficient budding of Marburg virus (MARV) and many other enveloped viruses. Interaction between components of the ESCRT machinery and viral proteins is predominantly mediated by short tetrapeptide motifs, known as late domains. MARV contains late domain motifs in the matrix protein VP40 and in the genome-encapsidating nucleoprotein (NP). The PSAP late domain motif of NP recruits the ESCRT-I protein tumor susceptibility gene 101 (Tsg101). Here, we generated a recombinant MARV encoding NP with a mutated PSAP late domain (rMARV(PSAPmut)). rMARV(PSAPmut) was attenuated by up to one log compared with recombinant wild-type MARV (rMARV(wt)), formed smaller plaques and exhibited delayed virus release. Nucleocapsids in rMARV(PSAPmut)-infected cells were more densely packed inside viral inclusions and more abundant in the cytoplasm than in rMARV(wt)-infected cells. A similar phenotype was detected when MARV-infected cells were depleted of Tsg101. Live-cell imaging analyses revealed that Tsg101 accumulated in inclusions of rMARV(wt)-infected cells and was co-transported together with nucleocapsids. In contrast, rMARV(PSAPmut) nucleocapsids did not display co-localization with Tsg101, had significantly shorter transport trajectories, and migration close to the plasma membrane was severely impaired, resulting in reduced recruitment into filopodia, the major budding sites of MARV. We further show that the Tsg101 interacting protein IQGAP1, an actin cytoskeleton regulator, was recruited into inclusions and to individual nucleocapsids together with Tsg101. Moreover, IQGAP1 was detected in a contrail-like structure at the rear end of migrating nucleocapsids. Down regulation of IQGAP1 impaired release of MARV. These results indicate that the PSAP motif in NP, which enables binding to Tsg101, is important for the efficient actin-dependent transport of nucleocapsids to the sites of budding. Thus, the interaction between NP and Tsg101 supports several steps of MARV assembly before virus fission.
Collapse
Affiliation(s)
- Olga Dolnik
- Institut für Virologie, Philipps Universität Marburg, Marburg, Germany
| | | | - Sonja Welsch
- EMBL Structural and Computational Biology Unit, Heidelberg, Germany
| | - Thomas Strecker
- Institut für Virologie, Philipps Universität Marburg, Marburg, Germany
| | - Gordian Schudt
- Institut für Virologie, Philipps Universität Marburg, Marburg, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps Universität Marburg, Marburg, Germany
- DZIF, Deutsches Zentrum für Infektionsforschung, Marburg, Germany
- * E-mail:
| |
Collapse
|
26
|
Radzimanowski J, Effantin G, Weissenhorn W. Conformational plasticity of the Ebola virus matrix protein. Protein Sci 2014; 23:1519-27. [PMID: 25159197 DOI: 10.1002/pro.2541] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/01/2014] [Accepted: 08/04/2014] [Indexed: 12/14/2022]
Abstract
Filoviruses are the causative agents of a severe and often fatal hemorrhagic fever with repeated outbreaks in Africa. They are negative sense single stranded enveloped viruses that can cross species barriers from its natural host bats to primates including humans. The small size of the genome poses limits to viral adaption, which may be partially overcome by conformational plasticity. Here we review the different conformational states of the Ebola virus (EBOV) matrix protein VP40 that range from monomers, to dimers, hexamers, and RNA-bound octamers. This conformational plasticity that is required for the viral life cycle poses a unique opportunity for development of VP40 specific drugs. Furthermore, we compare the structure to homologous matrix protein structures from Paramyxoviruses and Bornaviruses and we predict that they do not only share the fold but also the conformational flexibility of EBOV VP40.
Collapse
Affiliation(s)
- Jens Radzimanowski
- University Grenoble Alpes, UVHCI, F-38000, Grenoble, France; CNRS, UVHCI, F-38000, Grenoble, France
| | | | | |
Collapse
|
27
|
Garg H, Lee RTC, Tek NO, Maurer-Stroh S, Joshi A. Identification of conserved motifs in the West Nile virus envelope essential for particle secretion. BMC Microbiol 2013; 13:197. [PMID: 24007503 PMCID: PMC3766686 DOI: 10.1186/1471-2180-13-197] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/27/2013] [Indexed: 12/31/2022] Open
Abstract
Background Enveloped viruses utilize cellular membranes to bud from infected cells. The process of virion assembly and budding is often facilitated by the presence of certain conserved motifs within viral proteins in conjunction with cellular factors. We hence examined the West Nile Virus (WNV) Envelope protein for the presence of any such motifs and their functional characterization. Results We identified conserved 461PXAP464 and 349YCYL352 motifs in the WNV envelope glycoprotein bearing resemblance to retroviral late domains. Disruptive mutations of PXAP to LAAL and of the highly conserved Cys350 in the YCYL motif, led to a severe reduction in WNV particle production. Similar motifs in case of retroviruses are known to interact with components of host sorting machinery like PXAP with Tsg101 and YXXL with Alix. However, in the case of WNV, siRNA mediated depletion of Alix or Tsg101 did not have an effect on WNV release. Molecular modeling suggested that while the 461PXAP464 motif is surface accessible and could potentially interact with cellular proteins required for WNV assembly, the 349YCYL352 motif was found to be internal with Cys350 important for protein folding via disulphide bonding. Conclusions The conserved 461PXAP464 and 349YCYL352 motifs in the WNV envelope are indispensable for WNV particle production. Although these motifs bear sequence similarity to retroviral late domains and are essential for WNV assembly, they are functionally distinct suggesting that they are not the typical late domain like motifs of retroviruses and may play a role other than Alix/Tsg101 utilization/dependence.
Collapse
Affiliation(s)
- Himanshu Garg
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center, 5001 El Paso Dr, MSB-1 Annex, El Paso, TX 79905, USA.
| | | | | | | | | |
Collapse
|
28
|
Live-cell imaging of Marburg virus-infected cells uncovers actin-dependent transport of nucleocapsids over long distances. Proc Natl Acad Sci U S A 2013; 110:14402-7. [PMID: 23940347 DOI: 10.1073/pnas.1307681110] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Transport of large viral nucleocapsids from replication centers to assembly sites requires contributions from the host cytoskeleton via cellular adaptor and motor proteins. For the Marburg and Ebola viruses, related viruses that cause severe hemorrhagic fevers, the mechanism of nucleocapsid transport remains poorly understood. Here we developed and used live-cell imaging of fluorescently labeled viral and host proteins to characterize the dynamics and molecular requirements of nucleocapsid transport in Marburg virus-infected cells under biosafety level 4 conditions. The study showed a complex actin-based transport of nucleocapsids over long distances from the viral replication centers to the budding sites. Only after the nucleocapsids had associated with the matrix viral protein VP40 at the plasma membrane were they recruited into filopodia and cotransported with host motor myosin 10 toward the budding sites at the tip or side of the long cellular protrusions. Three different transport modes and velocities were identified: (i) Along actin filaments in the cytosol, nucleocapsids were transported at ∼200 nm/s; (ii) nucleocapsids migrated from one actin filament to another at ∼400 nm/s; and (iii) VP40-associated nucleocapsids moved inside filopodia at 100 nm/s. Unique insights into the spatiotemporal dynamics of nucleocapsids and their interaction with the cytoskeleton and motor proteins can lead to novel classes of antivirals that interfere with the trafficking and subsequent release of the Marburg virus from infected cells.
Collapse
|
29
|
Lipid droplet-binding protein TIP47 regulates hepatitis C Virus RNA replication through interaction with the viral NS5A protein. PLoS Pathog 2013; 9:e1003302. [PMID: 23593007 PMCID: PMC3623766 DOI: 10.1371/journal.ppat.1003302] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 02/27/2013] [Indexed: 12/16/2022] Open
Abstract
The nonstructural protein NS5A has emerged as a new drug target in antiviral therapies for Hepatitis C Virus (HCV) infection. NS5A is critically involved in viral RNA replication that takes place at newly formed membranes within the endoplasmic reticulum (membranous web) and assists viral assembly in the close vicinity of lipid droplets (LDs). To identify host proteins that interact with NS5A, we performed a yeast two-hybrid screen with the N-terminus of NS5A (amino acids 1–31), a well-studied α-helical domain important for the membrane tethering of NS5A. Our studies identified the LD-associated host protein, Tail-Interacting Protein 47 (TIP47) as a novel NS5A interaction partner. Coimmunoprecipitation experiments in Huh7 hepatoma cells confirmed the interaction of TIP47 with full-length NS5A. shRNA-mediated knockdown of TIP47 caused a more than 10-fold decrease in the propagation of full-length infectious HCV in Huh7.5 hepatoma cells. A similar reduction was observed when TIP47 was knocked down in cells harboring an autonomously replicating HCV RNA (subgenomic replicon), indicating that TIP47 is required for efficient HCV RNA replication. A single point mutation (W9A) in NS5A that disrupts the interaction with TIP47 but preserves proper subcellular localization severely decreased HCV RNA replication. In biochemical membrane flotation assays, TIP47 cofractionated with HCV NS3, NS5A, NS5B proteins, and viral RNA, and together with nonstructural viral proteins was uniquely distributed to lower-density LD-rich membrane fractions in cells actively replicating HCV RNA. Collectively, our data support a model where TIP47—via its interaction with NS5A—serves as a novel cofactor for HCV infection possibly by integrating LD membranes into the membranous web. Hepatitis C Virus (HCV) belongs to the Flaviviridae family, and is an enveloped, positive, single-stranded RNA virus containing a 9.6 kb genome. Plus-strand RNA viruses induce a highly regulated process of membrane rearrangements and novel vesicle formation in infected cells (the “membranous web” for HCV) to create a suitable environment for RNA replication as well as for the assembly and release of new virions. HCV assembly occurs close to lipid droplets (LDs), cell organelles involved in fat storage and utilization. The viral non-structural protein NS5A plays a critical role in both viral RNA replication that occurs within the membranous web and viral assembly at LDs. We identified the host protein TIP47 as a novel host interaction partner for NS5A. TIP47 is a LD-binding protein also known to function as cargo in late-endosome-to-Golgi vesicular transport. Our data support a model where the recruitment of TIP47 by NS5A is required for viral RNA replication, indicating that LDs play a previously unrecognized role not only in viral assembly but also in RNA replication.
Collapse
|
30
|
Fehling SK, Noda T, Maisner A, Lamp B, Conzelmann KK, Kawaoka Y, Klenk HD, Garten W, Strecker T. The microtubule motor protein KIF13A is involved in intracellular trafficking of the Lassa virus matrix protein Z. Cell Microbiol 2013; 15:315-34. [DOI: 10.1111/cmi.12095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/30/2012] [Accepted: 12/17/2012] [Indexed: 12/27/2022]
Affiliation(s)
- Sarah Katharina Fehling
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | | | - Andrea Maisner
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Boris Lamp
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer-Institute and Gene Center; Ludwig-Maximilians-University Munich; 81377 ; Munich; Germany
| | | | - Hans-Dieter Klenk
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Wolfgang Garten
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Thomas Strecker
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| |
Collapse
|
31
|
Mittler E, Kolesnikova L, Herwig A, Dolnik O, Becker S. Assembly of the Marburg virus envelope. Cell Microbiol 2012. [PMID: 23186212 DOI: 10.1111/cmi.12076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The key player to assemble the filamentous Marburg virus particles is the matrix protein VP40 which orchestrates recruitment of nucleocapsid complexes and the viral glycoprotein GP to the budding sites at the plasma membrane. Here, VP40 induces the formation of the viral particles, determines their morphology and excludes cellular proteins from the virions. Budding takes place at filopodia in non-polarized cells and at the basolateral cell pole in polarized epithelial cells. Molecular basis of how VP40 exerts its multifunctional role in these different processes is currently under investigation. Here we summarize recent data on structure-function relationships of VP40 and GP in connection with their function in assembly. Questions concerning the complex particle assembly, budding and release remaining enigmatic are addressed. Cytoplasmic domains of viral surface proteins often serve as a connection to the viral matrix protein or as binding sites for further viral or cellular proteins. A cooperation of MARV GP and VP40 building up the viral envelope can be proposed and is discussed in more detail in this review, as the cytoplasmic domain of GP represents an obvious interaction candidate because of its localization adjacent to the VP40 layer. Interestingly, truncation of the short cytoplasmic domain of GP neither inhibited interaction with VP40 nor incorporation of GP into progeny viral particles. Based on reverse genetics we generated recombinant virions expressing a GP mutant without the cytoplasmic tail. Investigations revealed attenuation in virus growth and an obvious defect in entry. Further investigations showed that the truncation of the cytoplasmic domain of GP impaired the structural integrity of the ectodomain, whichconsequently had impact on entry steps downstream of virus binding. Our data indicated that changes in the cytoplasmic domain are relayed over the lipid membrane to alter the function of the ectodomain.
Collapse
Affiliation(s)
- Eva Mittler
- Institute of Virology, Philipps University Marburg, Hans-Meerwein-Strasse 2, 35043 Marburg, Germany
| | | | | | | | | |
Collapse
|
32
|
Inhibition of Marburg virus budding by nonneutralizing antibodies to the envelope glycoprotein. J Virol 2012; 86:13467-74. [PMID: 23035224 DOI: 10.1128/jvi.01896-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The envelope glycoprotein (GP) of Marburg virus (MARV) and Ebola virus (EBOV) is responsible for virus entry into host cells and is known as the only target of neutralizing antibodies. While knowledge about EBOV-neutralizing antibodies and the mechanism for the neutralization of infectivity is being accumulated gradually, little is known about antibodies that can efficiently regulate MARV infectivity. Here we show that MARV GP-specific monoclonal antibodies AGP127-8 (IgG1) and MGP72-17 (IgM), which do not inhibit the GP-mediated entry of MARV into host cells, drastically reduced the budding and release of progeny viruses from infected cells. These antibodies similarly inhibited the formation of virus-like particles (VLPs) consisting of GP, the viral matrix protein, and nucleoprotein, whereas the Fab fragment of AGP127-8 showed no inhibitory effect. Morphological analyses revealed that filamentous VLPs were bunched on the surface of VLP-producing cells cultured in the presence of the antibodies. These results demonstrate a novel mechanism of the antibody-mediated inhibition of MARV budding, in which antibodies arrest unformed virus particles on the cell surface. Our data lead to the idea that such antibodies, like classical neutralizing antibodies, contribute to protective immunity against MARV and that the "classical" neutralizing activity is not the only indicator of a protective antibody that may be available for prophylactic and therapeutic use.
Collapse
|
33
|
Abstract
In 1967, the first reported filovirus hemorrhagic fever outbreak took place in Germany and the former Yugoslavia. The causative agent that was identified during this outbreak, Marburg virus, is one of the most deadly human pathogens. This article provides a comprehensive overview of our current knowledge about Marburg virus disease ranging from ecology to pathogenesis and molecular biology.
Collapse
Affiliation(s)
- Kristina Brauburger
- Department of Microbiology, School of Medicine and National Emerging Infectious Diseases Laboratories Institute, Boston University, Boston, MA 02118, USA.
| | | | | | | |
Collapse
|
34
|
Reynard O, Nemirov K, Page A, Mateo M, Raoul H, Weissenhorn W, Volchkov VE. Conserved proline-rich region of Ebola virus matrix protein VP40 is essential for plasma membrane targeting and virus-like particle release. J Infect Dis 2011; 204 Suppl 3:S884-91. [PMID: 21987765 DOI: 10.1093/infdis/jir359] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The matrix protein VP40 is essential for Ebola virus (EBOV) and Marburg virus assembly and budding at the plasma membrane. In this study we have investigated the effect of single amino acid substitutions in a conserved proline-rich region of the EBOV VP40 located in the carboxy-terminal part of the protein. We demonstrate that substitutions within this region result in an alteration of intracellular VP40 localization and also cause a reduction or a complete block of virus-like particle budding, a benchmark of VP40 function. Furthermore, some mutated VP40s revealed an enhanced binding with cellular Sec24C, a part of the coat protein complex II (COPII) vesicular transport system. Analysis of the 3-dimensional structure of VP40 revealed the spatial proximity of the proline-rich region and an earlier identified site of interaction with Sec24C, thus allowing us to hypothesize that the altered intracellular localization of the VP40 mutants is a consequence of defects in their interaction with COPII-mediated vesicular transport.
Collapse
Affiliation(s)
- Olivier Reynard
- Filovirus Laboratory, INSERM U758, Human Virology Department, Claude Bernard Université Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France
| | | | | | | | | | | | | |
Collapse
|
35
|
Makino A, Yamayoshi S, Shinya K, Noda T, Kawaoka Y. Identification of amino acids in Marburg virus VP40 that are important for virus-like particle budding. J Infect Dis 2011; 204 Suppl 3:S871-7. [PMID: 21987763 DOI: 10.1093/infdis/jir309] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The matrix protein VP40 of Marburg virus promotes the formation and release of virus-like particles (VLPs). Marburg virus VP40 interacts with cellular Tsg101 via its L domain motif; however, mutation of this motif does not affect VLP budding or the accumulation of VP40 in multivesicular bodies (MVBs), which are platforms for virus particle formation. To identify regions of Marburg virus VP40 that are important for VLP budding, we examined deletion mutants and alanine-scanning mutants at the N- and C-terminus of VP40 for their involvement in VLP budding. VLPs were not detected in the presence of alanine-replacement mutants at Ile39 and Thr40, and the level of VLP budding for the alanine mutant at Asn297 was decreased. Moreover, these mutants did not accumulate in MVBs. Our results suggest the involvement of a novel host factor(s) in VLP budding and VP40 transport to MVBs.
Collapse
Affiliation(s)
- Akiko Makino
- Department of Microbiology and Infectious Diseases, Division of Zoonosis, Graduate School of Medicine, Kobe University, Japan
| | | | | | | | | |
Collapse
|
36
|
Warfield KL, Aman MJ. Advances in virus-like particle vaccines for filoviruses. J Infect Dis 2011; 204 Suppl 3:S1053-9. [PMID: 21987741 DOI: 10.1093/infdis/jir346] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ebola virus (EBOV) and Marburg virus (MARV) are among the deadliest human pathogens, with no vaccines or therapeutics available. Multiple vaccine platforms have been tested for efficacy as prophylactic pretreatments or therapeutics for prevention of filovirus hemorrhagic fever. Most successful vaccines are based on a virus-vectored approach expressing the protective glycoprotein (GP); protein-based subunit and DNA vaccines have been tested with moderate success. Virus-like particle (VLP) vaccines have realized promising results when tested in both rodents and nonhuman primates. VLPs rely on the natural properties of the viral matrix protein (VP) 40 to drive budding of filamentous particles that can also incorporate ≥ 1 other filovirus protein, including GP, VP24, and nucleoprotein (NP). Filovirus VLP vaccines have used particles containing 2 or 3 (GP and VP40, with or without NP) viral proteins generated in either mammalian or insect cells. Early studies successfully demonstrated efficacy of bivalent VLP vaccines in rodents; more recent studies have shown the ability of the VLP vaccines containing GP, NP, and VP40 to confer complete homologous protection against Ebola virus and Marburg virus in a prophylactic setting against in macaques. This review will discuss published work to date regarding development of the VLP vaccines for prevention of lethal filovirus hemorrhagic fever.
Collapse
Affiliation(s)
- Kelly L Warfield
- Vaccine Development, Integrated Biotherapeutics, 21 Firstfield Rd, Ste 100, Gaithersburg, MD 20878, USA.
| | | |
Collapse
|
37
|
Kolesnikova L, Mittler E, Schudt G, Shams-Eldin H, Becker S. Phosphorylation of Marburg virus matrix protein VP40 triggers assembly of nucleocapsids with the viral envelope at the plasma membrane. Cell Microbiol 2011; 14:182-97. [DOI: 10.1111/j.1462-5822.2011.01709.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
38
|
Bharat TAM, Riches JD, Kolesnikova L, Welsch S, Krähling V, Davey N, Parsy ML, Becker S, Briggs JAG. Cryo-electron tomography of Marburg virus particles and their morphogenesis within infected cells. PLoS Biol 2011; 9:e1001196. [PMID: 22110401 PMCID: PMC3217011 DOI: 10.1371/journal.pbio.1001196] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 10/03/2011] [Indexed: 11/25/2022] Open
Abstract
Several major human pathogens, including the filoviruses, paramyxoviruses, and rhabdoviruses, package their single-stranded RNA genomes within helical nucleocapsids, which bud through the plasma membrane of the infected cell to release enveloped virions. The virions are often heterogeneous in shape, which makes it difficult to study their structure and assembly mechanisms. We have applied cryo-electron tomography and sub-tomogram averaging methods to derive structures of Marburg virus, a highly pathogenic filovirus, both after release and during assembly within infected cells. The data demonstrate the potential of cryo-electron tomography methods to derive detailed structural information for intermediate steps in biological pathways within intact cells. We describe the location and arrangement of the viral proteins within the virion. We show that the N-terminal domain of the nucleoprotein contains the minimal assembly determinants for a helical nucleocapsid with variable number of proteins per turn. Lobes protruding from alternate interfaces between each nucleoprotein are formed by the C-terminal domain of the nucleoprotein, together with viral proteins VP24 and VP35. Each nucleoprotein packages six RNA bases. The nucleocapsid interacts in an unusual, flexible "Velcro-like" manner with the viral matrix protein VP40. Determination of the structures of assembly intermediates showed that the nucleocapsid has a defined orientation during transport and budding. Together the data show striking architectural homology between the nucleocapsid helix of rhabdoviruses and filoviruses, but unexpected, fundamental differences in the mechanisms by which the nucleocapsids are then assembled together with matrix proteins and initiate membrane envelopment to release infectious virions, suggesting that the viruses have evolved different solutions to these conserved assembly steps.
Collapse
Affiliation(s)
- Tanmay A. M. Bharat
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - James D. Riches
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Sonja Welsch
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Verena Krähling
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Norman Davey
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Marie-Laure Parsy
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - John A. G. Briggs
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| |
Collapse
|
39
|
A concerted action of hepatitis C virus p7 and nonstructural protein 2 regulates core localization at the endoplasmic reticulum and virus assembly. PLoS Pathog 2011; 7:e1002144. [PMID: 21814513 PMCID: PMC3141040 DOI: 10.1371/journal.ppat.1002144] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 05/15/2011] [Indexed: 02/06/2023] Open
Abstract
Hepatitis C virus (HCV) assembly remains a poorly understood process. Lipid droplets (LDs) are thought to act as platforms for the assembly of viral components. The JFH1 HCV strain replicates and assembles in association with LD-associated membranes, around which viral core protein is predominantly detected. In contrast, despite its intrinsic capacity to localize to LDs when expressed individually, we found that the core protein of the high-titer Jc1 recombinant virus was hardly detected on LDs of cell culture-grown HCV (HCVcc)-infected cells, but was mainly localized at endoplasmic reticulum (ER) membranes where it colocalized with the HCV envelope glycoproteins. Furthermore, high-titer cell culture-adapted JFH1 virus, obtained after long-term culture in Huh7.5 cells, exhibited an ER-localized core in contrast to non-adapted JFH1 virus, strengthening the hypothesis that ER localization of core is required for efficient HCV assembly. Our results further indicate that p7 and NS2 are HCV strain-specific factors that govern the recruitment of core protein from LDs to ER assembly sites. Indeed, using expression constructs and HCVcc recombinant genomes, we found that p7 is sufficient to induce core localization at the ER, independently of its ion-channel activity. Importantly, the combined expression of JFH1 or Jc1 p7 and NS2 induced the same differential core subcellular localization detected in JFH1- vs. Jc1-infected cells. Finally, results obtained by expressing p7-NS2 chimeras between either virus type indicated that compatibilities between the p7 and the first NS2 trans-membrane domains is required to induce core-ER localization and assembly of extra- and intra-cellular infectious viral particles. In conclusion, we identified p7 and NS2 as key determinants governing the subcellular localization of HCV core to LDs vs. ER and required for initiation of the early steps of virus assembly.
Collapse
|
40
|
Yasuda J. Marburg virus budding: ESCRT of progeny virion to the outside of the cell. Future Virol 2010. [DOI: 10.2217/fvl.10.52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The major virion matrix protein of the Marburg virus (MARV), VP40, plays a key role in MARV assembly and budding, and its sole expression can produce enveloped virus-like particles. VP40 possesses only the PPXY motif as an L-domain critical for efficient virus budding, and interacts with the cellular ubiquitin ligase Nedd4. Functional abrogation of the cellular components of the endosomal sorting complexes required for transport complexes that participate in budding of multivesicular bodies into late endosomes by dominant-negative mutants or siRNA inhibited virus-like particle release, suggest that MARV budding utilizes the multivesicular bodies sorting pathway. In addition, tetherin/BST-2 was recently identified as an antiviral cellular factor that reduces MARV virus-like particle production. These findings may contribute to development of novel anti-MARV therapeutic strategies.
Collapse
Affiliation(s)
- Jiro Yasuda
- Fifth Biology Section for Microbiology, First Department of Forensic Science, National Research Institute of Police Science, Kashiwa 277–0882, Japan
| |
Collapse
|
41
|
Abstract
The filoviruses, Ebola and Marburg, utilize a multifaceted mechanism for assembly and budding of infectious virions from mammalian cells. Growing evidence not only demonstrates the importance of multiple viral proteins for efficient assembly and budding, but also the exploitation of various host proteins/pathways by the virus during this late stage of filovirus replication, including endocytic compartments, vacuolar protein sorting pathways, ubiquitination machinery, lipid rafts and cytoskeletal components. Continued elucidation of these complex and orchestrated virus-host interactions will provide a fundamental understanding of the molecular mechanisms of filovirus assembly/budding and ultimately lead to the development of novel viral- and/or host-oriented therapeutics to inhibit filovirus egress and spread. This article will focus on the most recent studies on host interactions and modulation of filovirus budding and summarize the key findings from these investigations.
Collapse
Affiliation(s)
- Yuliang Liu
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St., Philadelphia, PA 19104, USA
| | | |
Collapse
|
42
|
Trafficking of Sendai virus nucleocapsids is mediated by intracellular vesicles. PLoS One 2010; 5:e10994. [PMID: 20543880 PMCID: PMC2881874 DOI: 10.1371/journal.pone.0010994] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 05/17/2010] [Indexed: 11/25/2022] Open
Abstract
Background Paramyxoviruses are assembled at the plasma membrane budding sites after synthesis of all the structural components in the cytoplasm. Although viral ribonuclocapsid (vRNP) is an essential component of infectious virions, the process of vRNP translocation to assembly sites is poorly understood. Methodology/Principal Findings To analyze real-time trafficking of vRNPs in live infected cells, we created a recombinant Sendai virus (SeV), rSeVLeGFP, which expresses L protein fused to enhanced green fluorescent protein (eGFP). The rSeVLeGFP showed similar growth kinetics compared to wt SeV, and newly synthesized LeGFP could be detected as early as 8 h postinfection. The majority of LeGFP co-localized with other components of vRNPs, NP and P proteins, suggesting the fluorescent signals of LeGFP represent the locations of vRNPs. Analysis of LeGFP movement using time-lapse digital video microscopy revealed directional and saltatory movement of LeGFP along microtubules. Treatment of the cells with nocodazole restricted vRNP movement and reduced progeny virion production without affecting viral protein synthesis, suggesting the role of microtubules in vRNP trafficking and virus assembly. Further study with an electron microscope showed close association of vRNPs with intracellular vesicles present in infected cells. In addition, the vRNPs co-localized with Rab11a protein, which is known to regulate the recycling endocytosis pathway and Golgi-to-plasma membrane trafficking. Simultaneous movement between LeGFP and Rab11a was also observed in infected cells, which constitutively express mRFP-tagged Rab11a. Involvement of recycling endosomes in vRNP translocation was also suggested by the fact that vRNPs move concomitantly with recycling transferrin labeled with Alexa 594. Conclusions/Significance Collectively, our results strongly suggest a previously unrecognized involvement of the intracellular vesicular trafficking pathway in vRNP translocation and provide new insights into the transport of viral structural components to the assembly sites of enveloped viruses.
Collapse
|
43
|
Tsg101 is recruited by a late domain of the nucleocapsid protein to support budding of Marburg virus-like particles. J Virol 2010; 84:7847-56. [PMID: 20504928 DOI: 10.1128/jvi.00476-10] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nucleoprotein NP of Marburg virus (MARV) is the major component of the viral nucleocapsid, which also consists of the viral proteins VP35, L, and VP30, as well as the viral genome. During virus assembly at the plasma membrane, the nucleocapsids are enwrapped by the major matrix protein VP40 and the viral envelope, which contains the transmembrane glycoprotein GP. Upon recombinant expression, VP40 alone is able to induce the formation and release of virus-like particles (VLPs) that closely resemble the filamentous morphology of MARV particles. Release of these VP40-induced VLPs is partially dependent on the cellular ESCRT machinery, which interacts with a late-domain motif in VP40. Coexpression with NP significantly enhances the budding of VP40-induced VLPs by an unknown mechanism. In the present study we analyzed the impact of late domains present in NP on the release of VLPs. We observed that the ESCRT I protein Tsg101 was recruited by NP into NP-induced inclusions in the perinuclear region. In the presence of VP40, NP was then recruited to VP40-positive membrane clusters and, in turn, recruited Tsg101 via a C-terminal PSAP late-domain motif in NP. This PSAP motif also mediated a dramatically enhanced incorporation of Tsg101 into VLPs, and its deletion significantly diminished the positive effect of NP on the release of VLPs. Taken together, these data indicate that NP enhances budding of VLPs by recruiting Tsg101 to the VP40-positive budding site through a PSAP late-domain motif.
Collapse
|
44
|
Welsch S, Kolesnikova L, Krähling V, Riches JD, Becker S, Briggs JAG. Electron tomography reveals the steps in filovirus budding. PLoS Pathog 2010; 6:e1000875. [PMID: 20442788 PMCID: PMC2861712 DOI: 10.1371/journal.ppat.1000875] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 03/24/2010] [Indexed: 11/23/2022] Open
Abstract
The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a “submarine-like” budding with the helical nucleocapsid emerging parallel to the plasma membrane, and the other via perpendicular “rocket-like” protrusion. Here we have infected cells with Marburg virus under BSL-4 containment conditions, and reconstructed the sequence of steps in the budding process in three dimensions using electron tomography of plastic-embedded cells. We find that highly infectious filamentous particles are released at early stages in infection. Budding proceeds via lateral association of intracellular nucleocapsid along its whole length with the plasma membrane, followed by rapid envelopment initiated at one end of the nucleocapsid, leading to a protruding intermediate. Scission results in local membrane instability at the rear of the virus. After prolonged infection, increased vesiculation of the plasma membrane correlates with changes in shape and infectivity of released viruses. Our observations demonstrate a cellular determinant of virus shape. They reconcile the contrasting models of filovirus budding and allow us to describe the sequence of events taking place during budding and release of Marburg virus. We propose that this represents a general sequence of events also followed by other filamentous and rod-shaped viruses. The filoviruses, Marburg and Ebola, cause lethal hemorrhagic fever and are highest-priority bioterrorism agents. Filovirus particles contain a rod-like nucleocapsid and are normally filamentous, though other shapes are seen. It is poorly understood how such large filamentous particles are assembled and released from infected cells. Here we have studied Marburg virus production in infected cells using electron tomography. This technique allows virus particles to be visualized in three dimensions at different stages during assembly. We find that in early stages of virus production, highly infectious filamentous viruses are produced, whereas after prolonged infection poorly infectious spherical viruses are released. We also define the sequence of steps in filamentous virus release. The intracellular nucleocapsid first travels to the plasma membrane of the cell, where it binds laterally along its whole length. One end is then wrapped by the plasma membrane and wrapping proceeds rapidly until the virus protrudes vertically from the cell surface. The rear end of the virus particle then pinches off from the cell. We propose that other important filamentous and rod-shaped viruses also follow this series of steps of assembly and budding.
Collapse
Affiliation(s)
- Sonja Welsch
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Verena Krähling
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - James D. Riches
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail: (SB); (JAGB)
| | - John A. G. Briggs
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- * E-mail: (SB); (JAGB)
| |
Collapse
|
45
|
Urata S, Yasuda J. Regulation of Marburg virus (MARV) budding by Nedd4.1: a different WW domain of Nedd4.1 is critical for binding to MARV and Ebola virus VP40. J Gen Virol 2009; 91:228-34. [PMID: 19812267 DOI: 10.1099/vir.0.015495-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The VP40 matrix protein of Marburg virus (MARV) has been shown to be the driving force behind MARV budding, a process in which the PPPY L-domain motif of VP40 plays a critical role. Here, we report that Vps4B and Nedd4.1 play critical roles in MARV VP40-mediated budding. We showed that unidentified activities of the Nedd4.1 HECT domain, along with its E3 ubiquitin ligase activity, may be required for MARV budding. Moreover, we showed that the first WW domain of Nedd4.1, WW1, is critical for binding to MARV VP40, indicating that MARV VP40 and Ebola virus VP40 are recognized by a different WW domain of Nedd4.1. This is the first report showing that the viral L-domains containing PPxY have specificities for binding to WW domains. Our findings provide new insights into MARV budding, which may contribute to the development of novel anti-MARV therapeutic strategies.
Collapse
Affiliation(s)
- Shuzo Urata
- First Department of Forensic Science, National Research Institute of Police Science, Kashiwa 277-0882, Japan
| | | |
Collapse
|
46
|
Characterization of hepatitis C virus core protein multimerization and membrane envelopment: revelation of a cascade of core-membrane interactions. J Virol 2009; 83:9923-39. [PMID: 19605478 DOI: 10.1128/jvi.00066-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The molecular basis underlying hepatitis C virus (HCV) core protein maturation and morphogenesis remains elusive. We characterized the concerted events associated with core protein multimerization and interaction with membranes. Analyses of core proteins expressed from a subgenomic system showed that the signal sequence located between the core and envelope glycoprotein E1 is critical for core association with endoplasmic reticula (ER)/late endosomes and the core's envelopment by membranes, which was judged by the core's acquisition of resistance to proteinase K digestion. Despite exerting an inhibitory effect on the core's association with membranes, (Z-LL)(2)-ketone, a specific inhibitor of signal peptide peptidase (SPP), did not affect core multimeric complex formation, suggesting that oligomeric core complex formation proceeds prior to or upon core attachment to membranes. Protease-resistant core complexes that contained both innate and processed proteins were detected in the presence of (Z-LL)(2)-ketone, implying that core envelopment occurs after intramembrane cleavage. Mutations of the core that prevent signal peptide cleavage or coexpression with an SPP loss-of-function D219A mutant decreased the core's envelopment, demonstrating that SPP-mediated cleavage is required for core envelopment. Analyses of core mutants with a deletion in domain I revealed that this domain contains sequences crucial for core envelopment. The core proteins expressed by infectious JFH1 and Jc1 RNAs in Huh7 cells also assembled into a multimeric complex, associated with ER/late-endosomal membranes, and were enveloped by membranes. Treatment with (Z-LL)(2)-ketone or coexpression with D219A mutant SPP interfered with both core envelopment and infectious HCV production, indicating a critical role of core envelopment in HCV morphogenesis. The results provide mechanistic insights into the sequential and coordinated processes during the association of the HCV core protein with membranes in the early phase of virus maturation and morphogenesis.
Collapse
|
47
|
Ebolavirus glycoprotein GP masks both its own epitopes and the presence of cellular surface proteins. J Virol 2009; 83:9596-601. [PMID: 19587051 DOI: 10.1128/jvi.00784-09] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ebolavirus (EBOV) is the etiological agent of a severe hemorrhagic fever with a high mortality rate. The spike glycoprotein (GP) is believed to be one of the major determinants of virus pathogenicity. In this study, we demonstrated the molecular mechanism responsible for the downregulation of surface markers caused by EBOV GP expression. We showed that expression of mature GP on the plasma membrane results in the masking of cellular surface proteins, including major histocompatibility complex class I. Overexpression of GP also results in the masking of certain antigenic epitopes on GP itself, causing an illusory effect of disappearance from the plasma membrane.
Collapse
|
48
|
Wei T, Hibino H, Omura T. Rice dwarf virus is engulfed into and released via vesicular compartments in cultured insect vector cells. J Gen Virol 2008; 89:2915-2920. [DOI: 10.1099/vir.0.2008/002063-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vector insect cells infected with Rice dwarf virus had vesicular compartments containing viral particles located adjacent to the viroplasm when examined by transmission electron and confocal microscopy. Such compartments were often at the periphery of infected cells. Inhibitors of vesicular transport, brefeldin A and monensin, and an inhibitor of myosin motor activity, butanedione monoxime, abolished the formation of such vesicles and prevented the release of viral particles from infected cells without significant effects on virus multiplication. Furthermore, the actin-depolymerizing drug, cytochalasin D, inhibited the formation of actin filaments without significantly interfering with formation of vesicular compartments and the release of viruses from treated cells. These results together revealed intracellular vesicular compartments as a mode for viral transport in and release from insect vector cells infected with a plant-infecting reovirus.
Collapse
Affiliation(s)
- Taiyun Wei
- National Agricultural Research Center, 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan
| | - Hiroyuki Hibino
- National Agricultural Research Center, 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan
| | - Toshihiro Omura
- National Agricultural Research Center, 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan
| |
Collapse
|
49
|
Kolesnikova L, Ryabchikova E, Shestopalov A, Becker S. Basolateral Budding of Marburg Virus: VP40 Retargets Viral Glycoprotein GP to the Basolateral Surface. J Infect Dis 2007; 196 Suppl 2:S232-6. [DOI: 10.1086/520584] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
50
|
Ascenzi P, Bocedi A, Heptonstall J, Capobianchi MR, Di Caro A, Mastrangelo E, Bolognesi M, Ippolito G. Ebolavirus and Marburgvirus: insight the Filoviridae family. Mol Aspects Med 2007; 29:151-85. [PMID: 18063023 DOI: 10.1016/j.mam.2007.09.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 09/28/2007] [Indexed: 11/26/2022]
Abstract
Ebolavirus and Marburgvirus (belonging to the Filoviridae family) emerged four decades ago and cause epidemics of haemorrhagic fever with high case-fatality rates. The genome of filoviruses encodes seven proteins. No significant homology is observed between filovirus proteins and any known macromolecule. Moreover, Marburgvirus and Ebolavirus show significant differences in protein homology. The natural maintenance cycle of filoviruses is unknown, the natural reservoir, the mode of transmission, the epidemic disease generation, and temporal dynamics are unclear. Lastly, Ebolavirus and Marburgvirus are considered as potential biological weapons. Vaccine appears the unique therapeutic frontier. Here, molecular and clinical aspects of filoviral haemorrhagic fevers are summarized.
Collapse
Affiliation(s)
- Paolo Ascenzi
- National Institute for Infectious Diseases IRCCS Lazzaro Spallanzani, Via Portuense 292, I-00149 Roma, Italy
| | | | | | | | | | | | | | | |
Collapse
|