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Tan J, Harlow J, Cecillon J, Nasheri N. Assessing the efficacy of different bead-based assays in capturing hepatitis E virus. J Virol Methods 2024; 324:114860. [PMID: 38061674 DOI: 10.1016/j.jviromet.2023.114860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/17/2023]
Abstract
Hepatitis E virus (HEV) generally causes acute liver infection in humans and its transmission could be waterborne, foodborne, bloodborne, or zoonotic. To date, there is no standard method for the detection of HEV from food and environmental samples. Herein, we explored the possibility of using magnetic beads for the capture and detection of HEV. For this purpose, we employed Dynabeads M-270 Epoxy magnetic beads, coated with different monoclonal antibodies (mAbs) against HEV capsid protein, and the Nanotrap Microbiome A Particle magnetic beads, which are coated with chemical affinity baits, to capture HEV-3 particles in suspension. Viral RNA was extracted by heat-shock or QIAamp viral RNA kit and subjected to quantification using digital-droplet RT-PCR (ddRT-PCR). We demonstrated that the mAb-coupled Dynabeads and the Nanotrap particles, both were able to successfully capture HEV-3. The latter, however had lower limit of detection (<140gc compared with <1400 gc) and significantly higher extraction efficiency in comparison to the mAb-coupled Dynabeads (41.1% vs 8.8%). We have also observed that viral RNA extraction by heat-shock is less efficient compared to using highly denaturing reagents in QIAmp viral RNA extraction kit. As such, magnetic beads have the potential to be used to capture HEV virions for research and surveillance purposes.
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Affiliation(s)
- Jeremy Tan
- National Food Virology Reference Centre, Bureau of Microbial Hazards, Food Directorate, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, ON, Canada
| | - Jennifer Harlow
- National Food Virology Reference Centre, Bureau of Microbial Hazards, Food Directorate, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada
| | - Jonathon Cecillon
- National Food Virology Reference Centre, Bureau of Microbial Hazards, Food Directorate, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, ON, Canada
| | - Neda Nasheri
- National Food Virology Reference Centre, Bureau of Microbial Hazards, Food Directorate, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, ON, Canada.
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2
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Jablunovsky A, Jose J. The Dynamic Landscape of Capsid Proteins and Viral RNA Interactions in Flavivirus Genome Packaging and Virus Assembly. Pathogens 2024; 13:120. [PMID: 38392858 PMCID: PMC10893219 DOI: 10.3390/pathogens13020120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
The Flavivirus genus of the Flaviviridae family of enveloped single-stranded RNA viruses encompasses more than 70 members, many of which cause significant disease in humans and livestock. Packaging and assembly of the flavivirus RNA genome is essential for the formation of virions, which requires intricate coordination of genomic RNA, viral structural, and nonstructural proteins in association with virus-induced, modified endoplasmic reticulum (ER) membrane structures. The capsid (C) protein, a small but versatile RNA-binding protein, and the positive single-stranded RNA genome are at the heart of the elusive flavivirus assembly process. The nucleocapsid core, consisting of the genomic RNA encapsidated by C proteins, buds through the ER membrane, which contains viral glycoproteins prM and E organized as trimeric spikes into the lumen, forming an immature virus. During the maturation process, which involves the low pH-mediated structural rearrangement of prM and E and furin cleavage of prM in the secretory pathway, the spiky immature virus with a partially ordered nucleocapsid core becomes a smooth, mature virus with no discernible nucleocapsid. This review focuses on the mechanisms of genome packaging and assembly by examining the structural and functional aspects of C protein and viral RNA. We review the current lexicon of critical C protein features and evaluate interactions between C and genomic RNA in the context of assembly and throughout the life cycle.
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Affiliation(s)
- Anastazia Jablunovsky
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA;
| | - Joyce Jose
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA;
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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3
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Eilts F, Labisch JJ, Orbay S, Harsy YMJ, Steger M, Pagallies F, Amann R, Pflanz K, Wolff MW. Stability studies for the identification of critical process parameters for a pharmaceutical production of the Orf virus. Vaccine 2023:S0264-410X(23)00722-3. [PMID: 37353451 DOI: 10.1016/j.vaccine.2023.06.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 06/25/2023]
Abstract
A promising new vaccine platform is based on the Orf virus, a viral vector of the genus Parapoxvirus, which is currently being tested in phase I clinical trials. The application as a vaccine platform mandates a well-characterised, robust, and efficient production process. To identify critical process parameters in the production process affecting the virus' infectivity, the Orf virus was subjected to forced degradation studies, including thermal, pH, chemical, and mechanical stress conditions. The tests indicated a robust virus infectivity within a pH range of 5-7.4 and in the presence of the tested buffering substances (TRIS, HEPES, PBS). The ionic strength up to 0.5 M had no influence on the Orf virus' infectivity stability for NaCl and MgCl2, while NH4Cl destabilized significantly. Furthermore, short-term thermal stress of 2d up to 37 °C and repeated freeze-thaw cycles (20cycles) did not affect the virus' infectivity. The addition of recombinant human serum albumin was found to reduce virus inactivation. Last, the Orf virus showed a low shear sensitivity induced by peristaltic pumps and mixing, but was sensitive to ultrasonication. The isoelectric point of the applied Orf virus genotype D1707-V was determined at pH3.5. The broad picture of the Orf virus' infectivity stability against environmental parameters is an important contribution for the identification of critical process parameters for the production process, and supports the development of a stable pharmaceutical formulation. The work is specifically relevant for enveloped (large DNA) viruses, like the Orf virus and like most vectored vaccine approaches.
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Affiliation(s)
- Friederike Eilts
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Jennifer J Labisch
- Lab Essentials Applications Development, Sartorius Stedim Biotech GmbH, August-Spindler-Straße 11, 37079 Goettingen, Germany; Institute of Technical Chemistry, Leibniz University Hannover, Callinstraße 3-9, 30167 Hannover, Lower Saxony, Germany
| | - Sabri Orbay
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Yasmina M J Harsy
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Marleen Steger
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Felix Pagallies
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15/3.008, 72076 Tuebingen, Germany
| | - Ralf Amann
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15/3.008, 72076 Tuebingen, Germany; Prime Vector Technologies, Herrenberger Straße 24, 72070 Tuebingen, Germany
| | - Karl Pflanz
- Lab Essentials Applications Development, Sartorius Stedim Biotech GmbH, August-Spindler-Straße 11, 37079 Goettingen, Germany
| | - Michael W Wolff
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany.
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4
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Solomon M, Liang C. Pseudotyped Viruses for Retroviruses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:61-84. [PMID: 36920692 DOI: 10.1007/978-981-99-0113-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Since the discovery of retroviruses, their genome and replication strategies have been extensively studied, leading to the discovery of several unique features that make them invaluable vectors for virus pseudotyping, gene delivery, and gene therapy. Notably, retroviral vectors enable the integration of a gene of interest into the host genome, they can be used to stably transduce both dividing and nondividing cells, and they can deliver relatively large genes. Today, retroviral vectors are commonly used for many research applications and have become an active tool in gene therapy and clinical trials. This chapter will discuss the important features of the retroviral genome and replication cycle that are crucial for the development of retroviral vectors, the different retrovirus-based vector systems that are commonly used, and finally the research and clinical applications of retroviral vectors.
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Affiliation(s)
- Magan Solomon
- Lady Davis Institute, Jewish General Hospital, McGill Centre for Viral Diseases, Montreal, QC, Canada.,Department of Medicine, McGill University, Montreal, QC, Canada
| | - Chen Liang
- Lady Davis Institute, Jewish General Hospital, McGill Centre for Viral Diseases, Montreal, QC, Canada. .,Department of Medicine, McGill University, Montreal, QC, Canada.
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5
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Hatmal MM, Al-Hatamleh MAI, Olaimat AN, Ahmad S, Hasan H, Ahmad Suhaimi NA, Albakri KA, Abedalbaset A, Kadir R, Mohamud R. Comprehensive Literature Review of Monkeypox. Emerg Microbes Infect 2022; 11:2600-2631. [PMID: 36263798 DOI: 10.1080/22221751.2022.2132882] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The current outbreak of monkeypox (MPX) infection has emerged as a global matter of concern in the last few months. MPX is a zoonosis caused by the MPX virus (MPXV), which is one of the Orthopoxvirus species. Thus, it is similar to smallpox caused by the variola virus, and smallpox vaccines and drugs have been shown to be protective against MPX. Although MPX is not a new disease and is rarely fatal, the current multi-country MPX outbreak is unusual because it is occurring in countries that are not endemic for MPXV. In this work, we reviewed the extensive literature available on MPXV to summarize the available data on the major biological, clinical and epidemiological aspects of the virus and the important scientific findings. This review may be helpful in raising awareness of MPXV transmission, symptoms and signs, prevention and protective measures. It may also be of interest as a basis for performance of studies to further understand MPXV, with the goal of combating the current outbreak and boosting healthcare services and hygiene practices.Trial registration: ClinicalTrials.gov identifier: NCT02977715..Trial registration: ClinicalTrials.gov identifier: NCT03745131..Trial registration: ClinicalTrials.gov identifier: NCT00728689..Trial registration: ClinicalTrials.gov identifier: NCT02080767..
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Affiliation(s)
- Ma'mon M Hatmal
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, Jordan
| | - Mohammad A I Al-Hatamleh
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia
| | - Amin N Olaimat
- Department of Clinical Nutrition and Dietetics, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, Jordan
| | - Suhana Ahmad
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia
| | - Hanan Hasan
- Department of Pathology, Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman, Jordan
| | | | | | | | - Ramlah Kadir
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia
| | - Rohimah Mohamud
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia
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6
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Liu CC, Liu YY, Zhou JF, Chen X, Chen H, Hu JH, Chen J, Zhang J, Sun RC, Wei JC, Go YY, Morita E, Zhou B. Cellular ESCRT components are recruited to regulate the endocytic trafficking and RNA replication compartment assembly during classical swine fever virus infection. PLoS Pathog 2022; 18:e1010294. [PMID: 35120190 PMCID: PMC8849529 DOI: 10.1371/journal.ppat.1010294] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/16/2022] [Accepted: 01/24/2022] [Indexed: 11/29/2022] Open
Abstract
As the important molecular machinery for membrane protein sorting in eukaryotic cells, the endosomal sorting and transport complexes (ESCRT-0/I/II/III and VPS4) usually participate in various replication stages of enveloped viruses, such as endocytosis and budding. The main subunit of ESCRT-I, Tsg101, has been previously revealed to play a role in the entry and replication of classical swine fever virus (CSFV). However, the effect of the whole ESCRT machinery during CSFV infection has not yet been well defined. Here, we systematically determine the effects of subunits of ESCRT on entry, replication, and budding of CSFV by genetic analysis. We show that EAP20 (VPS25) (ESCRT-II), CHMP4B and CHMP7 (ESCRT-III) regulate CSFV entry and assist vesicles in transporting CSFV from Clathrin, early endosomes, late endosomes to lysosomes. Importantly, we first demonstrate that HRS (ESCRT-0), VPS28 (ESCRT-I), VPS25 (ESCRT-II) and adaptor protein ALIX play important roles in the formation of virus replication complexes (VRC) together with CHMP2B/4B/7 (ESCRT-III), and VPS4A. Further analyses reveal these subunits interact with CSFV nonstructural proteins (NS) and locate in the endoplasmic reticulum, but not Golgi, suggesting the role of ESCRT in regulating VRC assembly. In addition, we demonstrate that VPS4A is close to lipid droplets (LDs), indicating the importance of lipid metabolism in the formation of VRC and nucleic acid production. Altogether, we draw a new picture of cellular ESCRT machinery in CSFV entry and VRC formation, which could provide alternative strategies for preventing and controlling the diseases caused by CSFV or other Pestivirus. ESCRT machinery can be responsible for virus budding and participate in regulating virus entry. However, little has been reported on its effects on VRC formation. Here, we uncover the novel roles of ESCRT-III and VPS4A in VRC assembly and update the additional subunits involved in the intracellular trafficking of CSFV. These data indicate that the ESCRT machinery promotes CSFV replication by forming VRC, which making it become nuclease-insensitive to avoid the recognition by the host antiviral surveillance system and the destruction of the viral RNA. Furthermore, we first demonstrate that the roles of ESCRT components in the formation of VRC in swine Pestivirus. Our findings highlight the growing evidence of diverse interactions between ESCRT subunits and viral factors of Flaviviridae family, and provide alternative strategies for preventing and controlling the diseases caused by CSFV or other Pestivirus.
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Affiliation(s)
- Chun-chun Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Ya-yun Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jiang-fei Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Xi Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Huan Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jia-huan Hu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jing Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jin Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Rui-cong Sun
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jian-chao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yun Young Go
- Department of Infectious Diseases and Public Health, City University of Hong Kong, Hong Kong SAR, China
| | - Eiji Morita
- Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan
| | - Bin Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- * E-mail:
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7
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Li Y, Liu D, Wang Y, Su W, Liu G, Dong W. The Importance of Glycans of Viral and Host Proteins in Enveloped Virus Infection. Front Immunol 2021; 12:638573. [PMID: 33995356 PMCID: PMC8116741 DOI: 10.3389/fimmu.2021.638573] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/15/2021] [Indexed: 12/15/2022] Open
Abstract
Animal viruses are parasites of animal cells that have characteristics such as heredity and replication. Viruses can be divided into non-enveloped and enveloped viruses if a lipid bilayer membrane surrounds them or not. All the membrane proteins of enveloped viruses that function in attachment to target cells or membrane fusion are modified by glycosylation. Glycosylation is one of the most common post-translational modifications of proteins and plays an important role in many biological behaviors, such as protein folding and stabilization, virus attachment to target cell receptors and inhibition of antibody neutralization. Glycans of the host receptors can also regulate the attachment of the viruses and then influence the virus entry. With the development of glycosylation research technology, the research and development of novel virus vaccines and antiviral drugs based on glycan have received increasing attention. Here, we review the effects of host glycans and viral proteins on biological behaviors of viruses, and the opportunities for prevention and treatment of viral infectious diseases.
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Affiliation(s)
- Yuqing Li
- Department of Biochemistry and Molecular Biology, Institute of Glycobiology, Dalian Medical University, Dalian, China
| | - Dongqi Liu
- The Queen's University of Belfast Joint College, China Medical University, Shenyang, China
| | - Yating Wang
- Department of Biochemistry and Molecular Biology, Institute of Glycobiology, Dalian Medical University, Dalian, China
| | - Wenquan Su
- Dalian Medical University, Dalian, China
| | - Gang Liu
- Department of Biochemistry and Molecular Biology, Institute of Glycobiology, Dalian Medical University, Dalian, China
| | - Weijie Dong
- Department of Biochemistry and Molecular Biology, Institute of Glycobiology, Dalian Medical University, Dalian, China
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8
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Genoyer E, Kulej K, Hung CT, Thibault PA, Azarm K, Takimoto T, Garcia BA, Lee B, Lakdawala S, Weitzman MD, López CB. The Viral Polymerase Complex Mediates the Interaction of Viral Ribonucleoprotein Complexes with Recycling Endosomes during Sendai Virus Assembly. mBio 2020; 11:e02028-20. [PMID: 32843550 PMCID: PMC7448285 DOI: 10.1128/mbio.02028-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 11/20/2022] Open
Abstract
Paramyxoviruses are negative-sense single-stranded RNA viruses that comprise many important human and animal pathogens, including human parainfluenza viruses. These viruses bud from the plasma membrane of infected cells after the viral ribonucleoprotein complex (vRNP) is transported from the cytoplasm to the cell membrane via Rab11a-marked recycling endosomes. The viral proteins that are critical for mediating this important initial step in viral assembly are unknown. Here, we used the model paramyxovirus, murine parainfluenza virus 1, or Sendai virus (SeV), to investigate the roles of viral proteins in Rab11a-driven virion assembly. We previously reported that infection with SeV containing high levels of copy-back defective viral genomes (DVGs) (DVG-high SeV) generates heterogenous populations of cells. Cells enriched in full-length (FL) virus produce viral particles containing standard or defective viral genomes, while cells enriched in DVGs do not, despite high levels of defective viral genome replication. Here, we took advantage of this heterogenous cell phenotype to identify proteins that mediate interaction of vRNPs with Rab11a. We examined the roles of matrix protein and nucleoprotein and determined that their presence is not sufficient to drive interaction of vRNPs with recycling endosomes. Using a combination of mass spectrometry and comparative analyses of protein abundance and localization in DVG-high and FL-virus-high (FL-high) cells, we identified viral polymerase complex component protein L and, specifically, its cofactor C as interactors with Rab11a. We found that accumulation of L and C proteins within the cell is the defining feature that differentiates cells that proceed to viral egress from cells containing viruses that remain in replication phases.IMPORTANCE Paramyxoviruses are members of a family of viruses that include a number of pathogens imposing significant burdens on human health. In particular, human parainfluenza viruses are an important cause of pneumonia and bronchiolitis in children for which there are no vaccines or directly acting antivirals. These cytoplasmic replicating viruses bud from the plasma membrane and co-opt cellular endosomal recycling pathways to traffic viral ribonucleoprotein complexes from the cytoplasm to the membrane of infected cells. The viral proteins required for viral engagement with the recycling endosome pathway are still not known. Here, we used the model paramyxovirus Sendai virus, or murine parainfluenza virus 1, to investigate the role of viral proteins in this initial step of viral assembly. We found that the viral polymerase components large protein L and accessory protein C are necessary for engagement with recycling endosomes. These findings are important in identifying viral proteins as potential targets for development of antivirals.
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Affiliation(s)
- Emmanuelle Genoyer
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Katarzyna Kulej
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Chuan Tien Hung
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Patricia A Thibault
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kristopher Azarm
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Toru Takimoto
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Benjamin A Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Benhur Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Seema Lakdawala
- Department of Microbiology & Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Matthew D Weitzman
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Carolina B López
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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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.
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A simple method for isolation of cell-associated viral particles from cell culture. J Virol Methods 2017; 249:194-196. [PMID: 28923314 DOI: 10.1016/j.jviromet.2017.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/14/2017] [Accepted: 09/15/2017] [Indexed: 11/21/2022]
Abstract
A common method for cell-associated virus isolation involves disruption of infected cells by a combination of hypotonic burst, freeze-thaw cycles (F-T) and sonication. This protocol was also originally used for the preparation of cell-free extract containing the MX strain of lymphocytic choriomeningitis virus (LCMV), which is preferentially propagated by cell-to-cell contact and does not release distinct virions into the medium. In the present study, we compared different approaches to virus isolation. Based on virus yield, we show that deionized water lysis is the fastest and most effective method for releasing LCMV MX infectious viral particles from persistently infected cells. Moreover, we demonstrate that freeze-thaw cycles and sonication do not improve virus isolation. This simple protocol could be used for isolation of other viruses, the life cycle of which is strictly cell-associated and therefore are difficult to release in large amounts from host cells.
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Abstract
To continue the chain of infection, a virus must undergo the process of replication to create new, infectious virions that are able to infect other cells of the body or subsequent hosts. After gaining entry into the body, a virus makes physical contact with and crosses the plasma membrane of a target cell. Inside, it releases and replicates its genome while facilitating the manufacture of its proteins by host ribosomes. How this is carried out depends upon the type of viral nucleic acid. Virus particles are assembled from these newly synthesized biological molecules and become infectious virions. Finally, the virions are released from the cell to continue the process of infection.
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Abstract
Viruses have evolved to exploit the vast complexity of cellular processes for their success within the host cell. The entry mechanisms of enveloped viruses (viruses with a surrounding outer lipid bilayer membrane) are usually classified as being either endocytotic or fusogenic. Different mechanisms have been proposed for Alphavirus entry and genome delivery. Indirect observations led to a general belief that enveloped viruses can infect cells either by protein-assisted fusion with the plasma membrane in a pH-independent manner or by endocytosis and fusion with the endocytic vacuole in a low-pH environment. The mechanism of Alphavirus penetration has been recently revisited using direct observation of the processes by electron microscopy under conditions of different temperatures and time progression. Under conditions nonpermissive for endocytosis or any vesicular transport, events occur which allow the entry of the virus genome into the cells. When drug inhibitors of cellular functions are used to prevent entry, only ionophores are found to significantly inhibit RNA delivery. Arboviruses are agents of significant human and animal disease; therefore, strategies to control infections are needed and include development of compounds which will block critical steps in the early infection events. It appears that current evidence points to an entry mechanism, in which alphaviruses infect cells by direct penetration of cell plasma membranes through a pore structure formed by virus and, possibly, host proteins.
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Structural analysis of respiratory syncytial virus reveals the position of M2-1 between the matrix protein and the ribonucleoprotein complex. J Virol 2014; 88:7602-17. [PMID: 24760890 DOI: 10.1128/jvi.00256-14] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Respiratory syncytial virus (RSV), a member of the Paramyxoviridae family of nonsegmented, negative-sense, single-stranded RNA genome viruses, is a leading cause of lower respiratory tract infections in infants, young children, and the elderly or immunocompromised. There are many open questions regarding the processes that regulate human RSV (hRSV) assembly and budding. Here, using cryo-electron tomography, we identified virus particles that were spherical, filamentous, and asymmetric in structure, all within the same virus preparation. The three particle morphologies maintained a similar organization of the surface glycoproteins, matrix protein (M), M2-1, and the ribonucleoprotein (RNP). RNP filaments were traced in three dimensions (3D), and their total length was calculated. The measurements revealed the inclusion of multiple full-length genome copies per particle. RNP was associated with the membrane whenever the M layer was present. The amount of M coverage ranged from 24% to 86% in the different morphologies. Using fluorescence light microscopy (fLM), direct stochastic optical reconstruction microscopy (dSTORM), and a proximity ligation assay (PLA), we provide evidence illustrating that M2-1 is located between RNP and M in isolated viral particles. In addition, regular spacing of the M2-1 densities was resolved when hRSV viruses were imaged using Zernike phase contrast (ZPC) cryo-electron tomography. Our studies provide a more complete characterization of the hRSV virion structure and substantiation that M and M2-1 regulate virus organization. IMPORTANCE hRSV is a leading cause of lower respiratory tract infections in infants and young children as well as elderly or immunocompromised individuals. We used cryo-electron tomography and Zernike phase contrast cryo-electron tomography to visualize populations of purified hRSV in 3D. We observed the three distinct morphologies, spherical, filamentous, and asymmetric, which maintained comparable organizational profiles. Depending on the virus morphology examined, the amount of M ranged from 24% to 86%. We complemented the cryo-imaging studies with fluorescence microscopy, dSTORM, and a proximity ligation assay to provide additional evidence that M2-1 is incorporated into viral particles and is positioned between M and RNP. The results highlight the impact of M and M2-1 on the regulation of hRSV organization.
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Abstract
mRNA has become an important alternative to DNA as a tool for cell reprogramming. To be expressed, exogenous DNA must be transmitted through the cell cytoplasm and placed into the nucleus. In contrast, exogenous mRNA simply has to be delivered into the cytoplasm. This can result in a highly uniform transfection of the whole population of cells, an advantage that has not been observed with DNA transfer. The use of mRNA, instead of DNA, in medical applications increases protocol safety by abolishing the risk of transgene insertion into host genomes. In this chapter, we review the aspects of mRNA structure and function that are important for its "transgenic" behavior, such as the composition of mRNA molecules and complexes with RNA binding proteins, localization of mRNA in cytoplasmic compartments, translation, and the duration of mRNA expression. In immunotherapy, mRNA is employed in reprogramming of antigen presenting cells (vaccination) and cytolytic lymphocytes. Other applications include generation of induced pluripotent stem (iPS) cells, and genome engineering with modularly assembled nucleases. The most investigated applications of mRNA technology are also reviewed here.
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Vancini R, Wang G, Ferreira D, Hernandez R, Brown DT. Alphavirus genome delivery occurs directly at the plasma membrane in a time- and temperature-dependent process. J Virol 2013; 87:4352-9. [PMID: 23388718 PMCID: PMC3624389 DOI: 10.1128/jvi.03412-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 01/19/2013] [Indexed: 12/14/2022] Open
Abstract
It is widely held that arboviruses such as the alphavirus Sindbis virus gain entry into cells by a process of receptor-mediated endocytosis followed by membrane fusion in the acid environment of the endosome. We have used an approach of direct observation of Sindbis virus entry into cells by electron microscopy and immunolabeling of virus proteins with antibodies conjugated to gold beads. We found that upon attaching to the cell surface, intact RNA-containing viruses became empty shells that could be identified only by antibody labeling. We found that the rate at which full particles were converted to empty particles increased with time and temperature. We found that this entry event takes place at temperatures that inhibit both endosome formation and membrane fusion. We conclude that entry of alphaviruses is by direct penetration of cell plasma membranes through a pore structure formed by virus and, possibly, host proteins.
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Affiliation(s)
- Ricardo Vancini
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Gongbo Wang
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Davis Ferreira
- Instituto de Microbiologia and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem (INCTBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raquel Hernandez
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Dennis T. Brown
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
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Avinoam O, Podbilewicz B. Eukaryotic cell-cell fusion families. CURRENT TOPICS IN MEMBRANES 2012; 68:209-34. [PMID: 21771501 DOI: 10.1016/b978-0-12-385891-7.00009-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Ori Avinoam
- Department of Biology, Technion, Israel Institute of Technology, Haifa, Israel
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Lorizate M, Kräusslich HG. Role of lipids in virus replication. Cold Spring Harb Perspect Biol 2011; 3:a004820. [PMID: 21628428 DOI: 10.1101/cshperspect.a004820] [Citation(s) in RCA: 181] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Viruses intricately interact with and modulate cellular membranes at several stages of their replication, but much less is known about the role of viral lipids compared to proteins and nucleic acids. All animal viruses have to cross membranes for cell entry and exit, which occurs by membrane fusion (in enveloped viruses), by transient local disruption of membrane integrity, or by cell lysis. Furthermore, many viruses interact with cellular membrane compartments during their replication and often induce cytoplasmic membrane structures, in which genome replication and assembly occurs. Recent studies revealed details of membrane interaction, membrane bending, fission, and fusion for a number of viruses and unraveled the lipid composition of raft-dependent and -independent viruses. Alterations of membrane lipid composition can block viral release and entry, and certain lipids act as fusion inhibitors, suggesting a potential as antiviral drugs. Here, we review viral interactions with cellular membranes important for virus entry, cytoplasmic genome replication, and virus egress.
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Affiliation(s)
- Maier Lorizate
- Department of Infectious Diseases, Virology, University Heidelberg, D-69120 Heidelberg, Germany
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Hunt SR, Hernandez R, Brown DT. Role of the vacuolar-ATPase in Sindbis virus infection. J Virol 2011; 85:1257-66. [PMID: 21084471 PMCID: PMC3020509 DOI: 10.1128/jvi.01864-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 11/03/2010] [Indexed: 11/20/2022] Open
Abstract
Bafilomycin A(1) is a specific inhibitor of the vacuolar-ATPase (V-ATPase), which is responsible for pH homeostasis of the cell and for the acidification of endosomes. Bafilomycin A(1) has been commonly used as a method of inhibition of infection by viruses known or suspected to follow the path of receptor-mediated endocytosis and low-pH-mediated membrane fusion. The exact method of entry for Sindbis virus, the prototype alphavirus, remains undetermined. To further investigate the role of the V-ATPase in Sindbis virus infection, the effects of bafilomycin A(1) on the infection of BHK and insect cells by Sindbis virus were studied. Bafilomycin A(1) was found to block the expression of a virus-encoded reporter gene in both infection and transfection of BHK cells. The inhibitory effects of bafilomycin A(1) were found to be reversible. The results suggest that in BHK cells in the presence of bafilomycin A(1), virus RNA enters the cell and is translated, but replication and proper folding of the product proteins requires the function of the V-ATPase. Bafilomycin A(1) had no significant effect on the outcome of infection in insect cells.
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Affiliation(s)
- Sabrina R. Hunt
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Raquel Hernandez
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Dennis T. Brown
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695
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