1
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Ramirez JM, Calderon-Zavala AC, Balaram A, Heldwein EE. In vitro reconstitution of herpes simplex virus 1 fusion identifies low pH as a fusion co-trigger. mBio 2023; 14:e0208723. [PMID: 37874146 PMCID: PMC10746285 DOI: 10.1128/mbio.02087-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 10/25/2023] Open
Abstract
IMPORTANCE HSV-1 causes lifelong, incurable infections and diseases ranging from mucocutaneous lesions to fatal encephalitis. Fusion of viral and host membranes is a critical step in HSV-1 infection of target cells that requires multiple factors on both the viral and host sides. Due to this complexity, many fundamental questions remain unanswered, such as the identity of the viral and host factors that are necessary and sufficient for HSV-1-mediated membrane fusion and the nature of the fusion trigger. Here, we developed a simplified in vitro fusion assay to examine the fusion requirements and identified low pH as a co-trigger for virus-mediated fusion in vitro. We hypothesize that low pH has a critical role in cell entry and, potentially, pathogenesis.
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Affiliation(s)
- J. Martin Ramirez
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
- Medical Scientist Training Program, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ariana C. Calderon-Zavala
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ariane Balaram
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ekaterina E. Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
- Medical Scientist Training Program, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
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2
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Sharma M, Marin M, Wu H, Prikryl D, Melikyan GB. Human Immunodeficiency Virus 1 Preferentially Fuses with pH-Neutral Endocytic Vesicles in Cell Lines and Human Primary CD4+ T-Cells. ACS NANO 2023; 17:17436-17450. [PMID: 37589658 PMCID: PMC10510587 DOI: 10.1021/acsnano.3c05508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/14/2023] [Indexed: 08/18/2023]
Abstract
Despite extensive efforts, the principal sites of productive HIV-1 entry in different target cells─plasma membrane (PM) vs endosomes─remain controversial. To delineate the site(s) of HIV-1 fusion, we implemented a triple labeling approach that involves tagging pseudoviruses with the fluid-phase viral content marker, iCherry, the viral membrane marker, DiD, and the extraviral pH sensor, ecliptic pHluorin. The viral content marker iCherry is released into the cytoplasm upon virus-cell fusion irrespective of the sites of fusion. In contrast, the extent of dilution of the membrane marker upon fusion with the PM (loss of signal) vs the endosomal membrane (no change in punctate DiD appearance) discriminates between the principal sites of viral fusion. Additionally, ecliptic pHluorin incorporated into the viral membrane reports whether virus fusion occurs in acidic endosomes. Real-time single virus imaging in living HeLa-derived cells, a CD4+ T-cell line, and activated primary human CD4+ T-cells revealed a strong (80-90%) HIV-1 preference for fusion with endosomes. Intriguingly, we observed HIV-1 fusion only with pH-neutral intracellular vesicles and never with acidified endosomes. These endocytic fusion events are likely culminating in productive infection since endocytic inhibitors, such as EIPA, Pitstop2, and Dynasore, as well as a dominant-negative dynamin-2 mutant, inhibited HIV-1 infection in HeLa-derived and primary CD4+ T-cells. Furthermore, the inhibition of endocytosis in HeLa-derived cells promoted hemifusion at the PM but abrogated complete fusion. Collectively, these data reveal that the primary HIV-1 entry pathway in diverse cell types is through fusion with pH-neutral intracellular vesicles.
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Affiliation(s)
- Manish Sharma
- Department
of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Children’s
Healthcare of Atlanta, Atlanta, Georgia 30322, United States
| | - Mariana Marin
- Department
of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Children’s
Healthcare of Atlanta, Atlanta, Georgia 30322, United States
| | - Hui Wu
- Department
of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - David Prikryl
- Department
of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Gregory B. Melikyan
- Department
of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Children’s
Healthcare of Atlanta, Atlanta, Georgia 30322, United States
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3
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Morandi MI, Busko P, Ozer-Partuk E, Khan S, Zarfati G, Elbaz-Alon Y, Abou Karam P, Napso Shogan T, Ginini L, Gil Z, Regev-Rudzki N, Avinoam O. Extracellular vesicle fusion visualized by cryo-electron microscopy. PNAS NEXUS 2022; 1:pgac156. [PMID: 36714848 PMCID: PMC9802263 DOI: 10.1093/pnasnexus/pgac156] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/30/2022] [Accepted: 08/09/2022] [Indexed: 02/01/2023]
Abstract
Extracellular vesicles (EVs) transfer bioactive molecules between cells in a process reminiscent of enveloped viruses. EV cargo delivery is thought to occur by protein-mediated and pH-dependent membrane fusion of the EV and the cellular membrane. However, there is a lack of methods to identify the fusion proteins and resolve their mechanism. We developed and benchmarked an in vitro biophysical assay to investigate EV membrane fusion. The assay was standardized by directly comparing EV and viral fusion with liposomes. We show that EVs and retroviruses fuse with liposomes mimicking the membrane composition of the late endosome in a pH- and protein-dependent manner. Moreover, we directly visualize the stages of membrane fusion using cryo-electron tomography. We find that, unlike most retroviruses, EVs remain fusogenic after acidification and reneutralization. These results provide novel insights into the EV cargo delivery mechanism and an experimental approach to identify the EV fusion machinery.
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Affiliation(s)
- Mattia I Morandi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Petro Busko
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Efrat Ozer-Partuk
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Suman Khan
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Giulia Zarfati
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yael Elbaz-Alon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Paula Abou Karam
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | | | - Lana Ginini
- Faculty of Health, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Ziv Gil
- Faculty of Health, Bar Ilan University, Ramat-Gan 5290002, Israel,Head and Neck Center, Holy Family Hospital, Nazareth 1641100, Israel
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4
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Virosome, a promising delivery vehicle for siRNA delivery and its novel preparation method. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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A Naturally Occurring Polymorphism in the Base of Sudan Virus Glycoprotein Decreases Glycoprotein Stability in a Species-Dependent Manner. J Virol 2021; 95:e0107321. [PMID: 34232742 DOI: 10.1128/jvi.01073-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sudan virus (SUDV) is one of five filoviruses that compose the genus Ebolavirus that has been responsible for episodic outbreaks in Central Africa. While the SUDV glycoprotein (GP) structure has been solved, GP residues that affect SUDV entry have not been extensively examined; many of the entry characteristics of SUDV GP are inferred from studies with the Zaire Ebola virus (EBOV) GP. Here, we investigate the effect on virus entry of a naturally occurring polymorphism in SUDV GP. Two of the earliest SUDV isolates contain glutamine at residue 95 (Q95) within the base region of GP1, whereas more recent SUDV isolates and GPs from all other ebolaviruses carry lysine at this position (K95). A K95Q change dramatically decreased titers of pseudovirions bearing SUDV GP, whereas the K95Q substitution in EBOV GP had no effect on titer. We evaluated virus entry to identify SUDV GP Q95-specific entry defects. The presence of Q95 in either EBOV or SUDV GP resulted in enhanced sensitivity of GP to proteolytic processing, yet this could not account for the SUDV-specific decrease in GP Q95 infectivity. We found that SUDV GP Q95 pseudovirions were more sensitive to imipramine, a GP-destabilizing antiviral. In contrast, SUDV GP K95 was more stable, requiring elevated temperatures to inhibit virus infection. Thus, the residue present at GP 95 has a critical role in stabilizing the SUDV glycoprotein, whereas this polymorphism has no effect on EBOV GP stability. These results provide novel insights into filovirus species-specific GP structure that affects virus infectivity. IMPORTANCE Filovirus outbreaks are associated with significant morbidity and mortality. Understanding the structural constraints of filoviral GPs that control virus entry into cells is critical for rational development of novel antivirals to block infection. Here, we identify a naturally occurring glutamine (Q) to lysine (K) polymorphism at residue 95 as a critical determinant of Sudan virus GP stability but not Zaire Ebola virus GP stability. We propose that glutamine at residue 95 in Sudan virus GP mediates decreased virus entry, thereby reducing infectivity. Our findings highlight a unique structural characteristic of Sudan virus GP that affects GP-mediated functionality. Further, it provides a cautionary note for the development of future broad-spectrum filovirus antivirals.
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6
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Tang X, Cao J, Zhang J, Xing J, Sheng X, Zhan W. Development of monoclonal antibody against glycoprotein of hirame novirhabdovirus (HIRRV) with virus neutralizing activity. Microb Pathog 2021; 154:104868. [PMID: 33771630 DOI: 10.1016/j.micpath.2021.104868] [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: 11/06/2020] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 11/15/2022]
Abstract
Hirame rhabdovirus (HIRRV) is one of the most important viruses of fish, posing a great threat to the fish industry in Asia and Europe. The glycoprotein (G) of HIRRV is known to play important roles in virus attachment and entry, making it an ideal target for both diagnosis and therapy. In this study, a truncated G of HIRRV was expressed as a fusion protein in Escherichia coli. Using the recombinant G protein (rG), monoclonal antibodies (mAbs) were prepared by the hybridoma technology. Subsequently, positive clones were screened by indirect enzyme-linked immunosorbent assay (ELISA) and further characterized by Western blot and immunofluorescence assay (IFA). ELISA results showed that two mAbs (3E5 and 4D10) could react with the rG, as well as the purified HIRRV. Western blot analysis showed that the mAbs belong to the IgG isotype and could recognize a 60 kDa viral protein, which is consistent with the molecular weight of G protein and determined to be the G protein of HIRRV by mass spectrometry. The virions in HIRRV-infected EPC could also be recognized by two mAbs in IFA. Moreover, neutralization assay showed that mAb 4D10 could significantly inhibit the proliferation of HIRRV and delay the development of cytopathic effect in viral-infected EPC cells, and in vivo neutralization assay also showed that mAb 4D10 could significantly reduce the mortality of HIRRV-infected flounder, indicating that mAb 4D10 can partially neutralize the HIRRV infection. Western blot analysis showed that mAb 4D10 could specifically bind the C-terminal domain of HIRRV-G protein. These results demonstrated that the produced mAbs could specifically recognize the G protein of HIRRV and displayed virus-neutralizing activity in vitro and in vivo, which could serve as effective detection probes and potential neutralizing antibodies for HIRRV.
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Affiliation(s)
- Xiaoqian Tang
- Laboratory of Pathology and Immunology of Aquatic Animals, KLM, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, No.1 Wenhai Road, Aoshanwei Town, Jimo, Qingdao, 266071, China
| | - Jing Cao
- Laboratory of Pathology and Immunology of Aquatic Animals, KLM, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China
| | - Jialin Zhang
- Laboratory of Pathology and Immunology of Aquatic Animals, KLM, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China
| | - Jing Xing
- Laboratory of Pathology and Immunology of Aquatic Animals, KLM, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, No.1 Wenhai Road, Aoshanwei Town, Jimo, Qingdao, 266071, China
| | - Xiuzhen Sheng
- Laboratory of Pathology and Immunology of Aquatic Animals, KLM, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China
| | - Wenbin Zhan
- Laboratory of Pathology and Immunology of Aquatic Animals, KLM, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, No.1 Wenhai Road, Aoshanwei Town, Jimo, Qingdao, 266071, China.
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7
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Shinohara T, Kanatsu-Shinohara M. Transgenesis and Genome Editing of Mouse Spermatogonial Stem Cells by Lentivirus Pseudotyped with Sendai Virus F Protein. Stem Cell Reports 2020; 14:447-461. [PMID: 32160520 PMCID: PMC7066332 DOI: 10.1016/j.stemcr.2020.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 12/31/2022] Open
Abstract
Spermatogonial stem cells (SSCs) serve as a resource for producing genetically modified animals. However, genetic manipulation of SSCs has met with limited success. Here, we show efficient gene transfer into SSCs via a lentivirus (FV-LV) using a fusion protein (F), a Sendai virus (SV) envelope protein involved in virion/cell membrane fusion. FV-LVs transduced cultured SSCs more efficiently than conventional LVs. Although SSCs infected with SV failed to produce offspring, those transduced with FV-LVs were fertile. In vivo microinjection showed that FV-LVs could penetrate not only the basement membrane of the seminiferous tubules but also the blood-testis barrier, which resulted in successful transduction of both spermatogenic cells and testicular somatic cells. Cultured SSCs transfected with FV-LVs that express drug-inducible CRISPR/Cas9 against Kit or Sycp3 showed impaired spermatogenesis upon transplantation and drug treatment in vivo. Thus, FV-LVs provide an efficient method for functional analysis of genes involved in SSCs and spermatogenesis. Sendai virus-derived F protein enhances lentiviral infection of male germ cells Transfected spermatogonial stem cells undergo germline transmission Lentivirus pseudotyped with F protein penetrates the blood-testis barrier This method is compatible with in vivo conditional gene editing
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Affiliation(s)
- Takashi Shinohara
- Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo, Kyoto 606-8501, Japan.
| | - Mito Kanatsu-Shinohara
- Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo, Kyoto 606-8501, Japan
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8
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Tomás HA, Mestre DA, Rodrigues AF, Guerreiro MR, Carrondo MJT, Coroadinha AS. Improved GaLV-TR Glycoproteins to Pseudotype Lentiviral Vectors: Impact of Viral Protease Activity in the Production of LV Pseudotypes. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 15:1-8. [PMID: 31528654 PMCID: PMC6742969 DOI: 10.1016/j.omtm.2019.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 08/08/2019] [Indexed: 01/03/2023]
Abstract
Lentiviral vectors (LVs) are excellent tools for gene transfer into mammalian cells. It is noteworthy that the first gene therapy treatment using LVs was approved for commercialization in 2017. The G glycoprotein from rhabdovirus vesicular stomatitis virus (VSV-G) is the glycoprotein most used to pseudotype LVs, due to its high efficiency in transducing several cell types and its resistance to viral vector purification and storage conditions. However, VSV-G expression induces cytotoxicity, which limits LV production to short periods. As alternative to VSV-G, γ-retrovirus glycoproteins (4070A derived, GaLV derived, and RD114 derived) have been used to pseudotype both γ-retroviral vectors (RVs) and LVs. These glycoproteins do not induce cytotoxicity, allowing the development of stable LV producer cells. Additionally, these LV pseudotypes present higher transduction efficiencies of hematopoietic stem cells when compared to VSV-G. Here, new 4070A-, RD114-TR-, and GaLV-TR-derived glycoproteins were developed with the aim of improving its cytoplasmic tail R-peptide cleavage and thus increase LV infectious titers. The new glycoproteins were tested in transient LV production using the wild-type or the less active T26S HIV-1 protease. The GaLV-TR-derived glycoproteins were able to overcome titer differences observed between LV production using wild-type and T26S protease. Additionally, these glycoproteins were even able to increase LV titers, evidencing its potential as an alternative glycoprotein to pseudotype LVs.
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Affiliation(s)
- Hélio A Tomás
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Daniel A Mestre
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ana F Rodrigues
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Miguel R Guerreiro
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Manuel J T Carrondo
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ana Sofia Coroadinha
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.,The Discoveries Centre for Regenerative and Precision Medicine, New University of Lisbon, Lisbon, Portugal
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9
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Weed DJ, Dollery SJ, Komala Sari T, Nicola AV. Acidic pH Mediates Changes in Antigenic and Oligomeric Conformation of Herpes Simplex Virus gB and Is a Determinant of Cell-Specific Entry. J Virol 2018; 92:e01034-18. [PMID: 29925660 PMCID: PMC6096812 DOI: 10.1128/jvi.01034-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 02/07/2023] Open
Abstract
Herpes simplex virus (HSV) is an important human pathogen with a high worldwide seroprevalence. HSV enters epithelial cells, the primary site of infection, by a low-pH pathway. HSV glycoprotein B (gB) undergoes low pH-induced conformational changes, which are thought to drive membrane fusion. When neutralized back to physiological pH, these changes become reversible. Here, HSV-infected cells were subjected to short pulses of radiolabeling, followed by immunoprecipitation with a panel of gB monoclonal antibodies (MAbs), demonstrating that gB folds and oligomerizes rapidly and cotranslationally in the endoplasmic reticulum. Full-length gB from transfected cells underwent low-pH-triggered changes in oligomeric conformation in the absence of other viral proteins. MAbs to gB neutralized HSV entry into cells regardless of the pH dependence of the entry pathway, suggesting a conservation of gB function in distinct fusion mechanisms. The combination of heat and acidic pH triggered irreversible changes in the antigenic conformation of the gB fusion domain, while changes in the gB oligomer remained reversible. An elevated temperature alone was not sufficient to induce gB conformational change. Together, these results shed light on the conformation and function of the HSV-1 gB oligomer, which serves as part of the core fusion machinery during viral entry.IMPORTANCE Herpes simplex virus (HSV) causes infection of the mouth, skin, eyes, and genitals and establishes lifelong latency in humans. gB is conserved among all herpesviruses. HSV gB undergoes reversible conformational changes following exposure to acidic pH which are thought to mediate fusion and entry into epithelial cells. Here, we identified cotranslational folding and oligomerization of newly synthesized gB. A panel of antibodies to gB blocked both low-pH and pH-neutral entry of HSV, suggesting conserved conformational changes in gB regardless of cell entry route. Changes in HSV gB conformation were not triggered by increased temperature alone, in contrast to results with EBV gB. Acid pH-induced changes in the oligomeric conformation of gB are related but distinct from pH-triggered changes in gB antigenic conformation. These results highlight critical aspects of the class III fusion protein, gB, and inform strategies to block HSV infection at the level of fusion and entry.
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Affiliation(s)
- Darin J Weed
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Stephen J Dollery
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Tri Komala Sari
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Anthony V Nicola
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
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10
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Identification of a conserved neutralizing epitope in the G-protein of Chandipura virus. Arch Virol 2018; 163:3215-3223. [PMID: 30116984 DOI: 10.1007/s00705-018-3987-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/14/2018] [Indexed: 12/19/2022]
Abstract
Chandipura virus (CHPV), associated with an encephalitic illness in humans, has caused multiple outbreaks with high mortality in central and western India in recent years. The present study compares surface glycoprotein (G-protein) from prototype and recent outbreak strains using in silico tools and in vitro experiments. In silico epitope predictions (B-cell and T-helper cell) for the sequences, 3D structure prediction and comparison of the G-proteins of the strains: I653514 (Year 1965), CIN0327 (Year 2003) and 148974 (Year 2014) revealed that the CHPV G-protein is stable and antigenic determinants are conserved. A monoclonal antibody developed against strain CIN0327 (named NAbC) was found to neutralize prototype I653514 as well as the currently circulating strain 148974. In silico antigen-antibody interaction studies using molecular docking of predicted structures of NAbC and G-proteins of various CHPV strains led to the identification of a conserved neutralizing epitope in the fusion domain of G-protein, which also contained a putative T-helper peptide. The identification of a conserved neutralizing epitope in domain IV (fusion domain amino acids 53 to 172) of CHPV G-protein is an important finding that may have the scope towards the development of protective targets against CHPV infection.
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11
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Feliciano D, Nixon-Abell J, Lippincott-Schwartz J. Triggered Cell-Cell Fusion Assay for Cytoplasmic and Organelle Intermixing Studies. ACTA ACUST UNITED AC 2018; 81:e61. [PMID: 30102462 DOI: 10.1002/cpcb.61] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Different multicellular organisms undergo cell-cell fusion to form functional syncytia that support specialized functions necessary for proper development and survival. For years, monitoring the structural consequences of this process using live-cell imaging has been challenging due to the unpredictable timing of cell fusion events in tissue systems. Here we present a triggered vesicular stomatitis virus G-protein (VSV-G)-mediated cell-cell fusion assay that can be used to synchronize fusion between cells. This allows the study of cellular changes that occur during cell fusion. The process is induced using a fast wash of low pH isotonic buffer, promoting the fusion of plasma membranes of two or more adjacent cells within seconds. This approach is suitable for studying mixing of small cytoplasmic molecules between fusing cells as well as changes in organelle distribution and dynamics. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Daniel Feliciano
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
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12
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Qudrat A, Truong K. Autonomous Cell Migration to CSF1 Sources via a Synthetic Protein-Based System. ACS Synth Biol 2017; 6:1563-1571. [PMID: 28478671 DOI: 10.1021/acssynbio.7b00076] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inflammatory lesions, often seen in diseases such as rheumatoid arthritis, atherosclerosis and cancer, feature an acidic (i.e., low pH) microenvironment rampant with cytokines, such as CSF1. For potential therapeutic intervention targeted at these CSF1 sources, we have assembled a system of four proteins inside a cell (i.e., HEK293) that initially had no natural CSF1-seeking ability. This system included a newly engineered CSF1 chimera receptor (named CSF1Rchi), the previously engineered Ca2+ activated RhoA (i.e., CaRQ), vesicular stomatitis virus glycoprotein G (VSVG) and thymidine kinase (TK). The binding of CSF1 to the CSF1Rchi generated a Ca2+ signal that activated CaRQ-mediated cellular blebbing, allowing autonomous cell migration toward the CSF1 source. Next, the VSVG protein allowed these engineered cells to fuse with the CSF1 source cells, upon low pH induction. Finally, these cells underwent death postganciclovir treatment, via the TK suicide mechanism. Hence, this protein system could potentially serve as the basis of engineering a cell to target inflammatory lesions in diseases featuring a microenvironment with high levels of CSF1 and low pH.
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Affiliation(s)
- Anam Qudrat
- Institute of Biomaterials
and Biomedical Engineering, University of Toronto, 164 College
Street, Toronto, Ontario M5S 3G9, Canada
| | - Kevin Truong
- Institute of Biomaterials
and Biomedical Engineering, University of Toronto, 164 College
Street, Toronto, Ontario M5S 3G9, Canada
- Edward
S. Rogers, Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Circle, Toronto, Ontario M5S 3G4, Canada
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13
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Mosabbir AA, Truong K. Ca 2+ -mediated rewiring of cell homing and fusion to VEGF sources. Cell Calcium 2017; 65:31-39. [DOI: 10.1016/j.ceca.2017.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 02/13/2017] [Accepted: 02/13/2017] [Indexed: 12/11/2022]
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14
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Qudrat A, Mosabbir AA, Truong K. Engineered Proteins Program Mammalian Cells to Target Inflammatory Disease Sites. Cell Chem Biol 2017; 24:703-711.e2. [PMID: 28552580 DOI: 10.1016/j.chembiol.2017.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 02/08/2017] [Accepted: 05/03/2017] [Indexed: 12/28/2022]
Abstract
Disease sites in atherosclerosis and cancer feature cell masses (e.g., plaques/tumors), a low pH extracellular microenvironment, and various pro-inflammatory cytokines such as tumor necrosis factor α (TNFα). The ability to engineer a cell to seek TNFα sources allows for targeted therapeutic delivery. To accomplish this, here we introduced a system of proteins: an engineered TNFα chimeric receptor (named TNFR1chi), a previously engineered Ca2+-activated RhoA (named CaRQ), vesicular stomatitis virus glycoprotein G (VSVG), and thymidine kinase. Upon binding TNFα, TNFR1chi generates a Ca2+ signal that in turn activates CaRQ-mediated non-apoptotic blebs that allow migration toward the TNFα source. Next, the addition of VSVG, upon low pH induction, causes membrane fusion of the engineered and TNFα source cells. Finally, after ganciclovir treatment cells undergo death via the thymidine kinase suicide mechanism. Hence, we assembled a system of proteins that forms the basis of engineering a cell to target inflammatory disease sites characterized by TNFα secretion and a low-pH microenvironment.
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Affiliation(s)
- Anam Qudrat
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street Room 407, Rosebrugh Building, Toronto, ON M5S 3G9, Canada
| | - Abdullah Al Mosabbir
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street Room 407, Rosebrugh Building, Toronto, ON M5S 3G9, Canada
| | - Kevin Truong
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street Room 407, Rosebrugh Building, Toronto, ON M5S 3G9, Canada; Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Circle, Toronto, ON M5S 3G4, Canada.
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15
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Yang Y, Hong Y, Nam GH, Chung JH, Koh E, Kim IS. Virus-Mimetic Fusogenic Exosomes for Direct Delivery of Integral Membrane Proteins to Target Cell Membranes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1605604. [PMID: 28165174 DOI: 10.1002/adma.201605604] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/30/2016] [Indexed: 06/06/2023]
Abstract
An efficient system for direct delivery of integral membrane proteins is successfully developed using a new biocompatible exosome-based platform. Fusogenic exosomes harboring viral fusogen, vascular stomatitis virus (VSV)-G protein, can fuse with and modify plasma membranes in a process called "membrane editing." This can facilitate the transfer of biologically active membrane proteins into the target cell membranes both in vitro and in vivo.
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Affiliation(s)
- Yoosoo Yang
- Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Yeonsun Hong
- Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Gi-Hoon Nam
- Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Jin Hwa Chung
- Bio-Imaging Center, Asan Institute for Life Science, Asan Medical Center, Seoul, 05505, Republic of Korea
| | - Eunee Koh
- Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - In-San Kim
- Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
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16
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Lin HP, Zheng DJ, Li YP, Wang N, Chen SJ, Fu YC, Xu WC, Wei CJ. Incorporation of VSV-G produces fusogenic plasma membrane vesicles capable of efficient transfer of bioactive macromolecules and mitochondria. Biomed Microdevices 2016; 18:41. [PMID: 27165101 DOI: 10.1007/s10544-016-0066-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The objective of this study was to determine if plasma membrane vesicles (PMVs) could be exploited for efficient transfer of macro-biomolecules and mitochondria. PMVs were derived from mechanical extrusion, and made fusogenic (fPMVs) by incorporating the glycoprotein G of vesicular stomatitis virus (VSV-G). Confocal microscopy examination revealed that cytoplasmic proteins and mitochondria were enclosed in PMVs as evidenced by tracing with cytoplasmically localized and mitochondria-targeted EGFP, respectively. However, no fluorescence signal was detected in PMVs from cells whose nucleus was labeled with an EGFP-tagged histone H2B. Consistently, qRT-PCR measurement showed that mRNA, miRNA and mitochondrial DNA decreased slightly; while nuclear DNA was not measureable. Further, Western blot analysis revealed that cytoplasmic and membrane-bound proteins fell inconspicuously while nuclear proteins were barely detecsle. In addition, fPMVs carrying cytoplamic DsRed proteins transduced about ~40 % of recipient cells. The transfer of protein was further confirmed by using the inducible Cre/loxP system. Mitochondria transfer was found in about 20 % recipient cells after incubation with fPMVs for 5 h. To verify the functionalities of transferred mitochondria, mitochodria-deficient HeLa cells (Rho0) were generated and cultivated with fPMVs. Cell enumeration demonstrated that adding fPMVs into culture media stimulated Rho0 cell growth by 100 % as compared to the control. Lastly, MitoTracker and JC-1 staining showed that transferred mitochondria maintained normal shape and membrane potential in Rho0 cells. This study established a time-saving and efficient approach to delivering proteins and mitochondria by using fPMVs, which would be helpful for finding a cure to mitochondria-associated diseases. Graphical abstract Schematic of the delivery of macro-biomolecules and organelles by fPMVs. VSV-G-expressing cells were extruded through a 3 μm polycarbonate membrane filter to generate fusogenic plasma membrane vesicles (fPMVs), which contain bioactive molecules and organelles but not the nucleus. fPMVs can be endocytosed by target cells, while the cargo is released due to low-pH induced membrane fusion. These nucleus-free fPMVs are efficient at delivery of cytoplasmic proteins and mitochondria, leading to recovery of mitochondrial biogenesis and proliferative ability in mitochondria-deficient cells.
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Affiliation(s)
- Hao-Peng Lin
- Multidisciplinary Research Center, Shantou University, Shantou, Guangdong, 515063, China
| | - De-Jin Zheng
- Multidisciplinary Research Center, Shantou University, Shantou, Guangdong, 515063, China
| | - Yun-Pan Li
- Multidisciplinary Research Center, Shantou University, Shantou, Guangdong, 515063, China
| | - Na Wang
- Multidisciplinary Research Center, Shantou University, Shantou, Guangdong, 515063, China
| | - Shao-Jun Chen
- Multidisciplinary Research Center, Shantou University, Shantou, Guangdong, 515063, China
| | - Yu-Cai Fu
- Laboratory of Cell Senescence, Shantou University Medical College, Shantou, Guangdong, 515041, China
| | - Wen-Can Xu
- Department of Endocrinology, First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, 515041, China
| | - Chi-Ju Wei
- Multidisciplinary Research Center, Shantou University, Shantou, Guangdong, 515063, China.
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17
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Hoffmann M, González Hernández M, Berger E, Marzi A, Pöhlmann S. The Glycoproteins of All Filovirus Species Use the Same Host Factors for Entry into Bat and Human Cells but Entry Efficiency Is Species Dependent. PLoS One 2016; 11:e0149651. [PMID: 26901159 PMCID: PMC4762945 DOI: 10.1371/journal.pone.0149651] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/03/2016] [Indexed: 11/19/2022] Open
Abstract
Ebola and marburgviruses, members of the family Filoviridae, can cause severe hemorrhagic fever in humans. The ongoing Ebola virus (EBOV) disease epidemic in Western Africa claimed more than 11,300 lives and was associated with secondary cases outside Africa, demonstrating that filoviruses pose a global health threat. Bats constitute an important natural reservoir of filoviruses, including viruses of the recently identified Cuevavirus genus within the Filoviridae family. However, the interactions of filoviruses with bat cells are incompletely understood. Here, we investigated whether filoviruses employ different strategies to enter human and bat cells. For this, we examined host cell entry driven by glycoproteins (GP) from all filovirus species into cell lines of human and fruit bat origin. We show that all GPs were able to mediate entry into human and most fruit bat cell lines with roughly comparable efficiency. In contrast, the efficiency of entry into the cell line EidNi/41 derived from a straw-colored fruit bat varied markedly between the GPs of different filovirus species. Furthermore, inhibition studies demonstrated that filoviruses employ the same host cell factors for entry into human, non-human primate and fruit bat cell lines, including cysteine proteases, two pore channels and NPC1 (Niemann-Pick C1 molecule). Finally, processing of GP by furin and the presence of the mucin-like domain in GP were dispensable for entry into both human and bat cell lines. Collectively, these results show that filoviruses rely on the same host cell factors for entry into human and fruit bat cells, although the efficiency of the usage of these factors might differ between filovirus species.
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Affiliation(s)
- Markus Hoffmann
- Infection Biology Unit, German Primate Center, Göttingen, Germany
- * E-mail: (SP); (MH)
| | | | - Elisabeth Berger
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Andrea Marzi
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate Center, Göttingen, Germany
- * E-mail: (SP); (MH)
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18
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Ortega-Villaizan M, Chico V, Martinez-Lopez A, Garcia-Valtanen P, Coll JM, Estepa A. Development of new therapeutical/adjuvant molecules by pepscan mapping of autophagy and IFN inducing determinants of rhabdoviral G proteins. Mol Immunol 2016; 70:118-24. [PMID: 26759988 DOI: 10.1016/j.molimm.2015.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/13/2015] [Accepted: 10/13/2015] [Indexed: 01/11/2023]
Abstract
Surface glycoproteins of enveloped virus are potent elicitors of both innate and adaptive host immune responses. Therefore, the identification of viral glycoprotein determinants directly implicated in the induction of these responses might be of special interest for designing new therapeutical/adjuvant molecules. In this work we review the contribution of the "pepscan" approach to the screening of viral functions in the sequence of glycoprotein G (gpG) of the fish rhabdovirus of viral hemorrhagic septicemia (VHSV). Among others, by scanning gpG peptides, it has been possible to identify and validate minimal determinants for gpG directly implicated in initiating the fish type I Interferon-associated immune responses as well as in the antiviral autophagy program. Further fine-tunning of the identified peptides in the gpG of VHSV has allowed designing novel adjuvants that decrease DNA vaccine requirements and identify possible innovative antiviral molecules. In addition, these results have also contributed to improve our knowledge on how to stimulate the fish immune system.
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Affiliation(s)
| | - V Chico
- IBMC, Miguel Hernandez University, 03202 Elche, Spain
| | | | | | - J M Coll
- INIA-SIGT-Biotechnology, 28040 Madrid, Spain.
| | - A Estepa
- IBMC, Miguel Hernandez University, 03202 Elche, Spain.
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19
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Hu S, Mohan Kumar D, Sax C, Schuler C, Akkina R. Pseudotyping of lentiviral vector with novel vesiculovirus envelope glycoproteins derived from Chandipura and Piry viruses. Virology 2015; 488:162-8. [PMID: 26650691 DOI: 10.1016/j.virol.2015.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/13/2015] [Accepted: 11/14/2015] [Indexed: 12/22/2022]
Abstract
While the envelope glycoprotein of vesicular stomatitis virus (VSV-G) is widely used for pseudotyping of lentiviral vectors, sub-optimal gene transfer into certain cell types and its sensitivity to inactivation by human complement hinders its broader applications. To find alternative candidates, here we evaluated two serologically distinct novel viral envelopes derived from Chandipura (CNV-G) and Piry (PRV-G) vesiculoviruses. Both permitted generation of high titer psuedotyped lentiviral vectors with a capacity for high efficiency gene transfer into various cell types from different species. In human lymphoid and hematopoietic stem cells, their transduction efficiency was significantly lower than that of VSV-G. However, both novel envelopes were found to be more resistant to inactivation by human serum complement compared to VSV-G. Thus CNV-G and PRV-G envelopes can be harnessed for multiple uses in the future based on the cell type that needs to be gene transduced and possibly for in vivo gene transfer.
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Affiliation(s)
- Shuang Hu
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Dipu Mohan Kumar
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Chelsea Sax
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Clayton Schuler
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Ramesh Akkina
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
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20
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Harrison JS, Higgins CD, O'Meara MJ, Koellhoffer JF, Kuhlman BA, Lai JR. Role of electrostatic repulsion in controlling pH-dependent conformational changes of viral fusion proteins. Structure 2014; 21:1085-96. [PMID: 23823327 DOI: 10.1016/j.str.2013.05.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/07/2013] [Accepted: 05/13/2013] [Indexed: 11/29/2022]
Abstract
Viral fusion proteins undergo dramatic conformational transitions during membrane fusion. For viruses that enter through the endosome, these conformational rearrangements are typically pH sensitive. Here, we provide a comprehensive review of the molecular interactions that govern pH-dependent rearrangements and introduce a paradigm for electrostatic residue pairings that regulate progress through the viral fusion coordinate. Analysis of structural data demonstrates a significant role for side-chain protonation in triggering conformational change. To characterize this behavior, we identify two distinct residue pairings, which we define as Histidine-Cation (HisCat) and Anion-Anion (AniAni) interactions. These side-chain pairings destabilize a particular conformation via electrostatic repulsion through side-chain protonation. Furthermore, two energetic control mechanisms, thermodynamic and kinetic, regulate these structural transitions. This review expands on the current literature by identification of these residue clusters, discussion of data demonstrating their function, and speculation of how these residue pairings contribute to the energetic controls.
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Affiliation(s)
- Joseph S Harrison
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA.
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21
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Menghani S, Chikhale R, Raval A, Wadibhasme P, Khedekar P. Chandipura Virus: an emerging tropical pathogen. Acta Trop 2012; 124:1-14. [PMID: 22721825 DOI: 10.1016/j.actatropica.2012.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Revised: 05/30/2012] [Accepted: 06/08/2012] [Indexed: 10/28/2022]
Abstract
Chandipura Virus (CHPV), a member of Rhabdoviridae, is responsible for an explosive outbreak in rural areas of India. It affects mostly children and is characterized by influenza-like illness and neurologic dysfunctions. It is transmitted by vectors such as mosquitoes, ticks and sand flies. An effective real-time one step reverse-transcriptase PCR assay method is adopted for diagnosis of this virus. CHPV has a negative sense RNA genome encoding five different proteins (N, P, M, G, and L). P protein plays a vital role in the virus's life cycle, while M protein is lethal in nature. There is no specific treatment available to date, symptomatic treatment involves use of mannitol to reduce brain edema. A Vero cell based vaccine candidate against CHPV was evaluated efficiently as a preventive agent against it. Prevention is the best method to suppress CHPV infection. Containment of disease transmitting vectors, maintaining good nutrition, health, hygiene and awareness in rural areas will help in curbing the menace of CHPV. Thus, to control virus transmission some immense preventive measures need to be attempted until a good anti-CHPV agent is developed.
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22
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Measles virus glycoprotein-pseudotyped lentiviral vectors are highly superior to vesicular stomatitis virus G pseudotypes for genetic modification of monocyte-derived dendritic cells. J Virol 2012; 86:5192-203. [PMID: 22345444 DOI: 10.1128/jvi.06283-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Dendritic cells (DCs) are potent antigen-presenting cells capable of promoting or regulating innate and adaptive immune responses against non-self antigens. To better understand the DC biology or to use them for immune intervention, a tremendous effort has been made to improve gene transfer in these cells. Lentiviral vectors (LVs) have conferred a huge advantage in that they can transduce nondividing cells such as human monocyte-derived DCs (MDDCs) but required high amounts of viral particles and/or accessory proteins such as Vpx or Vpr to achieve sufficient transduction rates. As a consequence, these LVs have been shown to cause dramatic functional modifications, such as the activation or maturation of transduced MDDCs. Taking advantage of new pseudotyped LVs, i.e., with envelope glycoproteins from the measles virus (MV), we demonstrate that MDDCs are transduced very efficiently with these new LVs compared to the classically used vesicular stomatitis virus G-pseudotyped LVs and thus allowed to achieve high transduction rates at relatively low multiplicities of infection. Moreover, in this experimental setting, no activation or maturation markers were upregulated, while MV-LV-transduced cells remained able to mature after an appropriate Toll-like receptor stimulation. We then demonstrate that our MV-pseudotyped LVs use DC-SIGN, CD46, and CD150/SLAM as receptors to transduce MDDCs. Altogether, our results show that MV-pseudotyped LVs provide the most accurate and simple viral method for efficiently transferring genes into MDDCs without affecting their activation and/or maturation status.
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23
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Hong JK, Je J, Song C, Hwang JE, Lee YH, Lim CO. Biochemical analysis of a Chinese cabbage phytocystatin-1. Genes Genomics 2011. [DOI: 10.1007/s13258-011-0150-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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24
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Jaskierny AJ, Panahi A, Feig M. Effect of flanking residues on the conformational sampling of the internal fusion peptide from Ebola virus. Proteins 2011; 79:1109-17. [PMID: 21246633 DOI: 10.1002/prot.22947] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Revised: 11/03/2010] [Accepted: 11/14/2010] [Indexed: 11/08/2022]
Abstract
Fusion peptides mediate viral and host-cell membrane fusion during viral entry. The monomeric form of the internal fusion peptide from Ebola virus was studied in membrane bilayer and water environments with computer simulations using replica exchange sampling and an implicit solvent description of the environment. Wild-type Ebola fusion peptide (EFP), the W8A mutant form, and an extended construct with flanking residues were examined. It was found that the monomeric form of wild-type EFP adopts coil-helix-coil structure with a short helix from residues 8 to 11 mostly sampling orientations parallel to the membrane surface. W8A mutation disrupts the helicity in the N-terminal region of the peptide and leads to a preference for slightly oblique orientation relative to the membrane surface. The addition of flanking residues also alters the fusion peptide conformation with either a helix-break-helix structure or extended N and C-termini and reduced membrane insertion. In water, the fusion peptide is found to adopt structures with low helicity.
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Affiliation(s)
- Adam J Jaskierny
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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25
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Kameyama Y, Kawabe Y, Ito A, Kamihira M. Antibody-dependent gene transduction using gammaretroviral and lentiviral vectors pseudotyped with chimeric vesicular stomatitis virus glycoprotein. J Virol Methods 2008; 153:49-54. [DOI: 10.1016/j.jviromet.2008.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 06/09/2008] [Accepted: 06/10/2008] [Indexed: 10/21/2022]
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26
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Basak S, Mondal A, Polley S, Mukhopadhyay S, Chattopadhyay D. Reviewing Chandipura: a vesiculovirus in human epidemics. Biosci Rep 2007; 27:275-98. [PMID: 17610154 PMCID: PMC7087735 DOI: 10.1007/s10540-007-9054-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Chandipura virus, a member of the rhabdoviridae family and vesiculovirus genera, has recently emerged as human pathogen that is associated with a number of outbreaks in different parts of India. Although, the virus closely resembles with the prototype vesiculovirus, Vesicular Stomatitis Virus, it could be readily distinguished by its ability to infect humans. Studies on Chandipura virus while shed light into distinct stages of viral infection; it may also allow us to identify potential drug targets for antiviral therapy. In this review, we have summarized our current understanding of Chandipura virus life cycle at the molecular detail with particular interest in viral RNA metabolisms, namely transcription, replication and packaging of viral RNA into nucleocapsid structure. Contemporary research on otherwise extensively studied family member Vesicular Stomatitis Virus has also been addressed to present a more comprehensive picture of vesiculovirus life cycle. Finally, we reveal examples of protein economy in Chandipura virus life-cycle whereby each viral protein has evolved complexity to perform multiple tasks.
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Affiliation(s)
- Soumen Basak
- Department of Chemistry and Biochemistry, Signaling Systems Laboratory, University of California, 9500 Gilman Dr, San Diego, CA 92093 USA
| | - Arindam Mondal
- Department of Biochemistry, Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35 B. C. Road, Kolkata, 700019 India
| | - Smarajit Polley
- Department of Biochemistry, Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35 B. C. Road, Kolkata, 700019 India
| | - Subhradip Mukhopadhyay
- Department of Biochemistry, Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35 B. C. Road, Kolkata, 700019 India
| | - Dhrubajyoti Chattopadhyay
- Department of Biochemistry, Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35 B. C. Road, Kolkata, 700019 India
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27
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Freitas MS, Gaspar LP, Lorenzoni M, Almeida FCL, Tinoco LW, Almeida MS, Maia LF, Degrève L, Valente AP, Silva JL. Structure of the Ebola fusion peptide in a membrane-mimetic environment and the interaction with lipid rafts. J Biol Chem 2007; 282:27306-27314. [PMID: 17545161 DOI: 10.1074/jbc.m611864200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The fusion peptide EBO(16) (GAAIGLAWIPYFGPAA) comprises the fusion domain of an internal sequence located in the envelope fusion glycoprotein (GP2) of the Ebola virus. This region interacts with the cellular membrane of the host and leads to membrane fusion. To gain insight into the mechanism of the peptide-membrane interaction and fusion, insertion of the peptide was modeled by experiments in which the tryptophan fluorescence and (1)H NMR were monitored in the presence of sodium dodecyl sulfate micelles or in the presence of detergent-resistant membrane fractions. In the presence of SDS micelles, EBO(16) undergoes a random coil-helix transition, showing a tendency to self-associate. The three-dimensional structure displays a 3(10)-helix in the central part of molecule, similar to the fusion peptides of many known membrane fusion proteins. Our results also reveal that EBO(16) can interact with detergent-resistant membrane fractions and strongly suggest that Trp-8 and Phe-12 are important for structure maintenance within the membrane bilayer. Replacement of tryptophan 8 with alanine (W8A) resulted in dramatic loss of helical structure, proving the importance of the aromatic ring in stabilizing the helix. Molecular dynamics studies of the interaction between the peptide and the target membrane also corroborated the crucial participation of these aromatic residues. The aromatic-aromatic interaction may provide a mechanism for the free energy coupling between random coil-helical transition and membrane anchoring. Our data shed light on the structural "domains" of fusion peptides and provide a clue for the development of a drug that might block the early steps of viral infection.
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Affiliation(s)
- Mônica S Freitas
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ
| | - Luciane P Gaspar
- Departamento de Virologia, Instituto Oswaldo Cruz, Fiocruz, 21040-360 Rio de Janeiro, RJ
| | - Marcos Lorenzoni
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo 14040-901, Ribeirão Preto, S.P., and
| | - Fabio C L Almeida
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ
| | - Luzineide W Tinoco
- Núcleo de Produtos Naturais, Laboratório de Analise e Desenvolvimento de Inibidores Enzimáticos, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ, Brazil
| | - Marcius S Almeida
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ
| | - Lenize F Maia
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ
| | - Léo Degrève
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo 14040-901, Ribeirão Preto, S.P., and
| | - Ana Paula Valente
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ
| | - Jerson L Silva
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ.
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28
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Roche S, Bressanelli S, Rey FA, Gaudin Y. Crystal structure of the low-pH form of the vesicular stomatitis virus glycoprotein G. Science 2006; 313:187-91. [PMID: 16840692 DOI: 10.1126/science.1127683] [Citation(s) in RCA: 331] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The vesicular stomatitis virus has an atypical membrane fusion glycoprotein (G) exhibiting a pH-dependent equilibrium between two forms at the virus surface. Membrane fusion is triggered during the transition from the high- to low-pH form. The structure of G in its low-pH form shows the classic hairpin conformation observed in all other fusion proteins in their postfusion conformation, in spite of a novel fold combining features of fusion proteins from classes I and II. The structure provides a framework for understanding the reversibility of the G conformational change. Unexpectedly, G is homologous to gB of herpesviruses, which raises important questions on viral evolution.
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Affiliation(s)
- Stéphane Roche
- CNRS, Unité Mixte de Recherche (UMR) 2472, Institut Fédératif de Recherche (IFR) 115, Virologie Moléculaire et Structurale, 91198, Gif sur Yvette, France
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D’Abusco AS, Casadio R, Tasco G, Giangiacomo L, Giartosio A, Calamia V, Di Marco S, Chiaraluce R, Consalvi V, Scandurra R, Politi L. Oligomerization of Sulfolobus solfataricus signature amidase is promoted by acidic pH and high temperature. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2006; 1:411-23. [PMID: 16243781 PMCID: PMC2685583 DOI: 10.1155/2005/543789] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The recombinant amidase from the hyperthermophylic archaeon Sulfolobus solfataricus (SSAM) a signature amidase, was cloned, purified and characterized. The enzyme is active on a large number of aliphatic and aromatic amides over the temperature range 60-95 degrees C and at pH values between 4.0 and 9.5, with an optimum at pH 5.0. The recombinant enzyme is in the form of a dimer of about 110 kD that reversibly associates into an octamer in a pH-dependent reaction. The pH dependence of the state of association was studied using gel permeation chromatography, analytical ultracentrifugation and dynamic light scattering techniques. At pH 7.0 all three techniques show the presence of two species, in about equal amounts, which is compatible with the existence of a dimeric and an octameric form. In decreasing pH, the dimers formed the octameric species and in increasing pH, the octameric species was converted to dimers. Above pH 8.0, only dimers were present, below pH 3.0 only octamers were present. The association of dimers into octamers decreased in non-polar solvents and increased with temperature. A mutant (Y41C) was obtained that did not show this behavior.
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Affiliation(s)
- Anna Scotto D’Abusco
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
| | - Rita Casadio
- CIRB Biocomputing Group, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - Gianluca Tasco
- CIRB Biocomputing Group, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - Laura Giangiacomo
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
| | - Anna Giartosio
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
| | - Valentina Calamia
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
| | | | - Roberta Chiaraluce
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
| | - Valerio Consalvi
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
| | - Roberto Scandurra
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
- Corresponding author ()
| | - Laura Politi
- Dipartimento di Scienze Biochimiche “A. Rossi-Fanelli,” Università “La Sapienza,” P.le A. Moro 5, 00185 Roma, Italy
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Diatta A, Piver E, Collin C, Vaudin P, Pagès JC. Semliki Forest virus-derived virus-like particles: characterization of their production and transduction pathways. J Gen Virol 2006; 86:3129-3136. [PMID: 16227236 DOI: 10.1099/vir.0.81103-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A procedure for the mobilization of Semliki Forest virus (SFV)-derived replicons using virus-like particles (VLPs) has been recently proposed. VLPs were obtained from 293T cells co-expressing the vesicular stomatitis virus glycoprotein (VSV-G) and a modified SFV replicon. Advantages of SFV VLPs include improved safety with a lack of sequence homology between components and reducing the risk of recombination events that could lead to the formation of autonomous particles. Characterization of SFV VLPs reveals a discrepancy in their ability to infect cells reported to be permissive. Furthermore, it was noted that not all viral envelopes were able to promote VLP release equally from transfected cells. These observations encouraged the examination of the molecular mechanisms supporting the different steps of VLP assembly and transduction. The use of a VSV-G related pathway for VLP entry into target cells was demonstrated; it was also observed that an internal ribosome entry site may not be adapted to control transgene expression in all cells. Finally, the need for a membrane-binding domain to obtain a fully active SFV replication complex and VLP formation was documented.
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Affiliation(s)
- A Diatta
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
| | - E Piver
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
| | - C Collin
- Biochemistry, Tours University Hospital, 37000 Tours, France
| | - P Vaudin
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
| | - J-C Pagès
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
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Waarts BL, Smit JM, Aneke OJC, McInerney GM, Liljeström P, Bittman R, Wilschut J. Reversible acid-induced inactivation of the membrane fusion protein of Semliki Forest virus. J Virol 2005; 79:7942-8. [PMID: 15919953 PMCID: PMC1143635 DOI: 10.1128/jvi.79.12.7942-7948.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, it has been shown that the exposure of Semliki Forest virus (SFV) to a mildly acidic environment induces a rapid and complete loss of the ability of the virus to bind and fuse to target membranes added subsequently. In the present study, incubation of SFV at low pH followed by a specific reneutralization step resulted in a partial reversion of this loss of viral fusion capacity, as assessed in a liposomal model system. Also, the ability of the viral E1 fusion protein to undergo liposome-stimulated trimerization was restored. Furthermore, acid-treated and neutralized SFV largely retained infectivity. Exposure of SFV to low pH induced dissociation of the E1/E2 heterodimer, which was not reversed upon neutralization. It is concluded that the SFV E1 fusion protein, after acid-induced dissociation from E2, rapidly adopts an intermediate, nontrimeric conformation in which it is no longer able to interact with target membrane lipids. Neutralization restores the ability of E1 to interact with membranes. This interaction, however, remains strictly dependent on low pH.
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Affiliation(s)
- Barry-Lee Waarts
- Department of Medical Microbiology, Molecular Virology Section, University Medical Center Groningen, Ant. Deusinglaan 1, 9713 AV Groningen, The Netherlands
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Da Poian AT, Carneiro FA, Stauffer F. Viral membrane fusion: is glycoprotein G of rhabdoviruses a representative of a new class of viral fusion proteins? Braz J Med Biol Res 2005; 38:813-23. [PMID: 15933774 DOI: 10.1590/s0100-879x2005000600002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Enveloped viruses always gain entry into the cytoplasm by fusion of their lipid envelope with a cell membrane. Some enveloped viruses fuse directly with the host cell plasma membrane after virus binding to the cell receptor. Other enveloped viruses enter the cells by the endocytic pathway, and fusion depends on the acidification of the endosomal compartment. In both cases, virus-induced membrane fusion is triggered by conformational changes in viral envelope glycoproteins. Two different classes of viral fusion proteins have been described on the basis of their molecular architecture. Several structural data permitted the elucidation of the mechanisms of membrane fusion mediated by class I and class II fusion proteins. In this article, we review a number of results obtained by our laboratory and by others that suggest that the mechanisms involved in rhabdovirus fusion are different from those used by the two well-studied classes of viral glycoproteins. We focus our discussion on the electrostatic nature of virus binding and interaction with membranes, especially through phosphatidylserine, and on the reversibility of the conformational changes of the rhabdovirus glycoprotein involved in fusion. Taken together, these data suggest the existence of a third class of fusion proteins and support the idea that new insights should emerge from studies of membrane fusion mediated by the G protein of rhabdoviruses. In particular, the elucidation of the three-dimensional structure of the G protein or even of the fusion peptide at different pH's might provide valuable information for understanding the fusion mechanism of this new class of fusion proteins.
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Affiliation(s)
- A T Da Poian
- Programa de Biologia Molecular e Biotecnologia, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ, Brasil.
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Mas V, Rocha A, Perez L, Coll JM, Estepa A. Reversible inhibition of spreading of in vitro infection and imbalance of viral protein accumulation at low pH in viral hemorrhagic septicemia rhabdovirus, a salmonid rhabdovirus. J Virol 2004; 78:1936-44. [PMID: 14747558 PMCID: PMC369509 DOI: 10.1128/jvi.78.4.1936-1944.2004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The inhibition of viral hemorrhagic septicemia rhabdovirus (VHSV) in vitro infection by pHs of <7 (low pH) has been previously reported. Nevertheless, the details of the mechanism underlying this effect remain obscure. We present evidence showing that low-pH inhibition occurs during a viral postadsorption step. Thus, while VHSV bound, replicated within single cells, and presented its G protein on the membranes of infected cells at both low and physiological pHs, both cell-to-cell spreading of infection (as estimated by the appearance of foci of infected cells) and fusion (as estimated by a syncytium assay) were inhibited by this low pH. The decreased VHSV titers and the inhibition of both cell-to-cell spreading of infection and fusion could be reversed by adjusting the pH to 7.5 at any time during infection. This effect should be taken into account to avoid false negatives in the diagnosis of VHSV by cell culture. On the other hand, the cell-to-cell spreading of infection at pH 7.5 could be stopped at any time by reducing the pH to 6.5. Since at low pH there were changes in the protein G conformation and smaller and imbalanced amounts of N with respect to M1, M2, and G viral proteins, alterations of the assembly and/or budding of VHSV are most probably involved in the absence of newly released infective virions.
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Affiliation(s)
- V Mas
- IBMC, Miguel Hernández University, 03202 Elche, Spain
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Jeetendra E, Ghosh K, Odell D, Li J, Ghosh HP, Whitt MA. The membrane-proximal region of vesicular stomatitis virus glycoprotein G ectodomain is critical for fusion and virus infectivity. J Virol 2003; 77:12807-18. [PMID: 14610202 PMCID: PMC262588 DOI: 10.1128/jvi.77.23.12807-12818.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2003] [Accepted: 08/22/2003] [Indexed: 11/20/2022] Open
Abstract
The glycoprotein (G) of vesicular stomatitis virus (VSV) is responsible for binding of virus to cells and for mediating virus entry following endocytosis by inducing fusion of the viral envelope with the endosomal membrane. The fusion peptide of G is internal (residues 116 to 137) and exhibits characteristics similar to those of other internal fusion peptides, but recent studies have implicated the region adjacent to the transmembrane domain as also being important for G-mediated membrane fusion. Sequence alignment of the membrane-proximal region of G from several different vesiculoviruses revealed that this domain is highly conserved, suggesting that it is important for G function. Mutational analysis was used to show that this region is not essential for G protein oligomerization, transport to the cell surface, or incorporation into virus particles but that it is essential for acid-induced membrane fusion activity and for virus infectivity. Deletion of the 13 membrane-proximal amino acids (N449 to W461) dramatically reduced cell-cell fusion activity and reduced virus infectivity approximately 100-fold, but mutation of conserved aromatic residues (W457, F458, and W461) either singly or together had only modest effects on cell-cell fusion activity; recombinant virus encoding these mutants replicated as efficiently as wild-type (WT) VSV. Insertion of heterologous sequences in the juxtamembrane region completely abolished membrane fusion activity and virus infectivity, as did deletion of residues F440 to N449. The insertion mutants showed some changes in pH-dependent conformational changes and in virus binding, which could partially explain the defects in membrane fusion activity, but all the other mutants were similar to WT G with respect to conformational changes and virus binding. These data support the hypothesis that the membrane-proximal domain contributes to G-mediated membrane fusion activity, yet the conserved aromatic residues are not essential for membrane fusion or virus infectivity.
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Affiliation(s)
- E Jeetendra
- Department of Molecular Sciences, University of Tennessee Health Sciences Center. GTx, Inc., Memphis, Tennessee 38163, USA
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