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Hodgson JJ, Chen RY, Blissard GW, Buchon N. Viral and cellular determinants of polarized trafficking of viral envelope proteins from insect-specific and insect-vectored viruses in insect midgut and salivary gland cells. J Virol 2024; 98:e0054024. [PMID: 39162433 DOI: 10.1128/jvi.00540-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 07/09/2024] [Indexed: 08/21/2024] Open
Abstract
Systemic viral infection of insects typically begins with the primary infection of midgut epithelial cells (enterocytes) and subsequent transit of the progeny virus in an apical-to-basal orientation into the hemocoel. For insect-vectored viruses, an oppositely oriented process (basal-to-apical transit) occurs upon secondary infection of salivary glands and is necessary for virus transmission to non-insect hosts. To examine this inversely oriented virus transit in these polarized tissues, we assessed the intracellular trafficking of two model viral envelope proteins (baculovirus GP64 and vesicular stomatitis virus G) in the midgut and salivary gland cells of the model insect, Drosophila melanogaster. Using fly lines that inducibly express either GP64 or VSV G, we found that each protein, expressed alone, was trafficked basally in midgut enterocytes. In salivary gland cells, VSV G was trafficked apically in most but not all cells, whereas GP64 was consistently trafficked basally. We demonstrated that a YxxØ motif present in both proteins was critical for basal trafficking in midgut enterocytes but dispensable for trafficking in salivary gland cells. Using RNAi, we found that clathrin adaptor protein complexes AP-1 and AP-3, as well as seven Rab GTPases, were involved in polarized VSV G trafficking in midgut enterocytes. Our results indicate that these viral envelope proteins encode the requisite information and require no other viral factors for appropriately polarized trafficking. In addition, they exploit tissue-specific differences in protein trafficking pathways to facilitate virus egress in the appropriate orientation for establishing systemic infections and vectoring infection to other hosts. IMPORTANCE Viruses that use insects as hosts must navigate specific routes through different insect tissues to complete their life cycles. The routes may differ substantially depending on the life cycle of the virus. Both insect pathogenic viruses and insect-vectored viruses must navigate through the polarized cells of the midgut epithelium to establish a systemic infection. In addition, insect-vectored viruses must also navigate through the polarized salivary gland epithelium for transmission. Thus, insect-vectored viruses appear to traffic in opposite directions in these two tissues. In this study, we asked whether two viral envelope proteins (VSV G and baculovirus GP64) alone encode the signals necessary for the polarized trafficking associated with their respective life cycles. Using Drosophila as a model to examine tissue-specific polarized trafficking of these viral envelope proteins, we identified one of the virus-encoded signals and several host proteins associated with regulating the polarized trafficking in the midgut epithelium.
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Affiliation(s)
- Jeffrey J Hodgson
- Department of Entomology, Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, USA
- Boyce Thompson Institute at Cornell University, Ithaca, New York, USA
| | - Robin Y Chen
- Department of Entomology, Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, USA
| | - Gary W Blissard
- Boyce Thompson Institute at Cornell University, Ithaca, New York, USA
| | - Nicolas Buchon
- Department of Entomology, Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, USA
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2
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Guo J, Li S, Bai L, Zhao H, Shang W, Zhong Z, Maimaiti T, Gao X, Ji N, Chao Y, Li Z, Du D. Structural transition of GP64 triggered by a pH-sensitive multi-histidine switch. Nat Commun 2024; 15:7668. [PMID: 39227374 PMCID: PMC11372198 DOI: 10.1038/s41467-024-51799-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 08/16/2024] [Indexed: 09/05/2024] Open
Abstract
The fusion of viruses with cellular membranes is a critical step in the life cycle of enveloped viruses. This process is facilitated by viral fusion proteins, many of which are conformationally pH-sensitive. The specifics of how changes in pH initiate this fusion have remained largely elusive. This study presents the cryo-electron microscopy (cryo-EM) structures of a prototype class III fusion protein, GP64, in its prefusion and early intermediate states, revealing the structural intermediates accompanying the membrane fusion process. The structures identify the involvement of a pH-sensitive switch, comprising H23, H245, and H304, in sensing the low pH that triggers the initial step of membrane fusion. The pH sensing role of this switch is corroborated by assays of cell-cell syncytium formation and dual dye-labeling. The findings demonstrate that coordination between multiple histidine residues acts as a pH sensor and activator. The involvement of a multi-histidine switch in viral fusion is applicable to fusogens of human-infecting thogotoviruses and other viruses, which could lead to strategies for developing anti-viral therapies and vaccines.
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Affiliation(s)
- Jinliang Guo
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shangrong Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Lisha Bai
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Huimin Zhao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wenyu Shang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Zhaojun Zhong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | | | - Xueyan Gao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ning Ji
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yanjie Chao
- CAS Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
| | - Zhaofei Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - Dijun Du
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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Fan Y, Wu P, Sun Q, Yu B, Zhang Y, Wei J, Pan G, Li C, Zhou Z. The development of single-chain antibody anchored on the BmE cell membrane to inhibit BmNPV infection. J Invertebr Pathol 2023; 198:107937. [PMID: 37209810 DOI: 10.1016/j.jip.2023.107937] [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: 02/04/2023] [Revised: 04/25/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023]
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) poses a significant threat to sericulture production, and traditional sanitation practices remain the main strategy for controlling BmNPV infection. Although RNAi targeting BmNPV genes engineered into transgenic silkworms has shown to be a promising approach in reducing viral infection, it cannot block viral entry into host cells. Therefore, there is an urgent need to develop new effective prevention and control measures. In this study, we screened a monoclonal antibody 6C5 that potently neutralizes BmNPV infection by clamping the internal fusion loop of the BmNPVglycoprotein64 (GP64). Furthermore, we cloned the VH and VL fragments of mAb-6C5 from the hybridoma cell, and the eukaryotic expression vector of scFv6C5 was constructed to anchor the antibody on the cell membrane. The GP64 fusion loop antibody-expressing cells exhibited a reduced capacity for BmNPV infection. The results from our study provide a novel BmNPV control strategy and lay the foundation for the future development of transgenic silkworms with improved antiviral efficacy.
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Affiliation(s)
- Youpeng Fan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China
| | - Pengfei Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China
| | - Quan Sun
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China
| | - Bin Yu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China
| | - Yonghua Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Junhong Wei
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China
| | - Guoqing Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China
| | - Chunfeng Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China
| | - Zeyang Zhou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing, 400715, China; College of Life Sciences, Chongqing Normal University, Chongqing 401331, China.
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Nishigami M, Uno Y, Tsumoto K. Microscopic Observation of Membrane Fusion between Giant Liposomes and Baculovirus Budded Viruses Activated by the Release of a Caged Proton. MEMBRANES 2023; 13:membranes13050507. [PMID: 37233568 DOI: 10.3390/membranes13050507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 05/02/2023] [Accepted: 05/05/2023] [Indexed: 05/27/2023]
Abstract
Baculovirus (Autographa californica multiple nucleopolyhedrovirus, AcMNPV) is an envelope virus possessing a fusogenic protein, GP64, which can be activated under weak acidic conditions close to those in endosomes. When the budded viruses (BVs) are bathed at pH 4.0 to 5.5, they can bind to liposome membranes with acidic phospholipids, and this results in membrane fusion. In the present study, using the caged-proton reagent 1-(2-nitrophenyl)ethyl sulfate, sodium salt (NPE-caged-proton), which can be uncaged by irradiation with ultraviolet light, we triggered the activation of GP64 by lowering the pH and observed membrane fusion on giant liposomes (giant unilamellar vesicles, GUVs) by visualizing the lateral diffusion of fluorescence emitted from a lipophilic fluorochrome (octadecyl rhodamine B chloride, R18) that stained viral envelopes of BVs. In this fusion, entrapped calcein did not leak from the target GUVs. The behavior of BVs prior to the triggering of membrane fusion by the uncaging reaction was closely monitored. BVs appeared to accumulate around a GUV with DOPS, implying that BVs preferred phosphatidylserine. The monitoring of viral fusion triggered by the uncaging reaction could be a valuable tool for revealing the delicate behavior of viruses affected by various chemical and biochemical environments.
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Affiliation(s)
- Misako Nishigami
- Division of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu 514-8507, Mie, Japan
| | - Yuki Uno
- Division of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu 514-8507, Mie, Japan
| | - Kanta Tsumoto
- Division of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu 514-8507, Mie, Japan
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5
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Zheng Q, Wang W, Zhao F, Lin S, Chen J. Identification and characterization of an envelope protein 168L in Cherax quadricarinatus iridovirus (CQIV). Virus Res 2023; 323:198967. [PMID: 36241037 PMCID: PMC10194265 DOI: 10.1016/j.virusres.2022.198967] [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: 09/02/2022] [Revised: 10/09/2022] [Accepted: 10/10/2022] [Indexed: 11/05/2022]
Abstract
Cherax quadricarinatus iridovirus (CQIV), a new member of family Iridoviridae, mainly infects the shrimps and crayfish with a high mortality rate. Previous gel-based LC-MS/MS study on CQIV has identified 30 structural proteins. In this study, one of the structural proteins, CQIV-168L, was selected for further analysis. RT-PCR and Western-blotting (WB) detection revealed that the transcript and the protein appeared late during infection of C. quadricarinatus cells and that the transcript was blocked by viral DNA replication inhibitor, indicating that CQIV-168L is a late expression gene. The specific antiserum against CQIV-168L was raised and immunofluorescence analysis showed that CQIV-168L was localized in the cytoplasm and associated with virus factories. Western-blotting (WB) assay suggested that CQIV-168L antiserum bound specifically to a 57-kDa protein in both the intact virions and the envelope fraction. As revealed by immunogold labeling, CQIV-168L was a component of the viral envelope. Findings in this work help to further understand the structure and entry mechanism of CQIV.
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Affiliation(s)
- Qin Zheng
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
| | - Wei Wang
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
| | - Furong Zhao
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
| | - Shen Lin
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
| | - Jianming Chen
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China.
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Cruz-Resendiz A, Acero G, Sampieri A, Gevorkian G, Salvador C, Escobar L, Rosendo-Pineda MJ, Medeiros M, Vaca L. An ambient-temperature stable nanoparticle-based vaccine for nasal application that confers long-lasting immunogenicity to carried antigens. Front Immunol 2022; 13:1057499. [DOI: 10.3389/fimmu.2022.1057499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 10/19/2022] [Indexed: 11/13/2022] Open
Abstract
Polyhedrins are viral proteins present in a large family of baculoviruses that form occlusion bodies (polyhedra). These structures protect the virus particles from the outside environment until they are ingested by susceptible insects. Occluded viruses can sustain inclement weather for long periods of time. Therefore, the polyhedra is a natural preservative that keeps the viral structure intact at ambient temperature for years. In a previous study we identified the first 110 amino acids from polyhedrin (PH(1-110)) as a good candidate to carry antigens of interest. As a proof of concept, we produced a fusion protein with PH(1-110) and the green fluorescent protein (PH(1-110)GFP). The fusion protein associates spontaneously during its synthesis resulting in the formation of nanoparticles. Nasal immunization with these nanoparticles and in the absence of any adjuvant, results in a robust immune response with the production of IgG immunoglobulins that remained elevated for months and that selectively recognize the GFP but not PH(1-110). These results indicate that PH(1-110) is poorly immunogenic but capable of enhancing the immune response to GFP.
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Vallbracht M, Klupp BG, Mettenleiter TC. Influence of N-glycosylation on Expression and Function of Pseudorabies Virus Glycoprotein gB. Pathogens 2021; 10:61. [PMID: 33445487 PMCID: PMC7827564 DOI: 10.3390/pathogens10010061] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 01/13/2023] Open
Abstract
Envelope glycoprotein (g)B is conserved throughout the Herpesviridae and mediates fusion of the viral envelope with cellular membranes for infectious entry and spread. Like all viral envelope fusion proteins, gB is modified by asparagine (N)-linked glycosylation. Glycans can contribute to protein function, intracellular transport, trafficking, structure and immune evasion. gB of the alphaherpesvirus pseudorabies virus (PrV) contains six consensus sites for N-linked glycosylation, but their functional relevance is unknown. Here, we investigated the occupancy and functional relevance of N-glycosylation sites in PrV gB. To this end, all predicted N-glycosylation sites were inactivated either singly or in combination by the introduction of conservative mutations (N➔Q). The resulting proteins were tested for expression, fusion activity in cell-cell fusion assays and complementation of a gB-deficient PrV mutant. Our results indicate that all six sites are indeed modified. However, while glycosylation at most sites was dispensable for gB expression and fusogenicity, inactivation of N154 and N700 affected gB processing by furin cleavage and surface localization. Although all single mutants were functional in cell-cell fusion and viral entry, simultaneous inactivation of all six N-glycosylation sites severely impaired fusion activity and viral entry, suggesting a critical role of N-glycans for maintaining gB structure and function.
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Affiliation(s)
| | | | - Thomas C. Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany; (M.V.); (B.G.K.)
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Zhang Y, Enden G, Wei W, Zhou F, Chen J, Merchuk JC. Baculovirus transit through insect cell membranes: A mechanistic approach. Chem Eng Sci 2020; 223:115727. [PMID: 32362678 PMCID: PMC7195021 DOI: 10.1016/j.ces.2020.115727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/15/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
A novel mechanistic model of the early stages of viral infection. Excellent fit to experimental evidence. The maximum number of virions that Sf9 cells can carry: 55 viruses/cell, is reported. Cells that carry virions on their surface, in their interior, or both are distinguished. Analytical mathematical solution renders satisfactory results.
Baculovirus systems are used for various purposes, but the kinetics of the infection process is not fully understood yet. We investigated the dynamics of virion movement from a medium toward the interior of insect cells and established a mechanistic model that shows an excellent fit to experimental results. It also makes possible a description of the viral dynamics on the cell surface. A novel measurement method was used to distinguish between infected cells that carry virions on their surfaces, cells that carry virions in their interior, and those carrying virions both inside and on their surface. The maximum number of virions carried by a cell: 55 viruses/cell, and the time required for viral internalization, 0.8h, are reported. This information is particularly useful for assessing the infection efficacy and the required number of virions needed to infect a given cell population. Although our model specifically concerns the infection process of Sf9 insect cells by baculovirus, it describes general features of viral infection. Some of the model features may eventually be applicable in the studies towards palliation of the COVID-19 outbreak.
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Affiliation(s)
- Youhong Zhang
- School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, LiuFang Campus, Guanggu 1st Road, Wuhan 430205 China.,Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, LiuFang Campus, Guanggu 1st Road, Wuhan 430205 China
| | - Giora Enden
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Wei Wei
- Institute of Marine Microbes and Ecospheres, Xiamen University (Xiang'an), Xiamen 361102, China
| | - Feng Zhou
- School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, LiuFang Campus, Guanggu 1st Road, Wuhan 430205 China
| | - Jie Chen
- School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, LiuFang Campus, Guanggu 1st Road, Wuhan 430205 China
| | - Jose C Merchuk
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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Critical Residues and Contacts within Domain IV of Autographa californica Multiple Nucleopolyhedrovirus GP64 Contribute to Its Refolding during Membrane Fusion. J Virol 2020; 94:JVI.01105-20. [PMID: 32699096 DOI: 10.1128/jvi.01105-20] [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] [Received: 06/02/2020] [Accepted: 07/19/2020] [Indexed: 01/14/2023] Open
Abstract
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) GP64 is a class III viral fusion protein that mediates low-pH-triggered membrane fusion during virus entry. Although the structure of GP64 in a postfusion conformation has been solved, its prefusion structure and the mechanism of how the protein refolds to execute fusion are unknown. In its postfusion structure, GP64 is composed of five domains (domains I to V). Domain IV (amino acids [aa] 374 to 407) contains two loops (loop 1 and loop 2) that form a hydrophobic pocket at the membrane-distal end of the molecule. To determine the roles of domain IV, we used alanine-scanning mutagenesis to replace each of the individual residues and the contact-forming residues within domain IV and evaluate their contributions to GP64-mediated membrane fusion and virus infection. In many cases, replacement of a single amino acid had no significant impact on GP64. However, replacement of R392 or disruption of the N381-N385, N384-Y388, N385-W393, or K389-W393 contact resulted in poor cell surface expression and fusion loss of the modified GP64, whereas replacement of E390 or G391 or disruption of the N381-K389, N381-Q401, or N381-I403 contact reduced the cell surface expression level of the constructs and the ability of GP64 to mediate fusion pore expansion. In contrast, replacement of N407 or disruption of contact D404-S406 appeared to restrict fusion pore expansion without affecting expression. Combined with the finding that these constructs remain in the prefusion conformation or have a dramatically less efficient transition from the prefusion to the postfusion state under acidic conditions, we proposed that domain IV is necessary for refolding of GP64 during membrane fusion.IMPORTANCE Baculovirus GP64 is grouped with rhabdovirus G, herpesvirus gB, and thogotovirus glycoproteins as a class III viral fusion protein. In their postfusion structures, these proteins contain five domains (domains I to V). Distinct from domain IV of rhabdovirus G and herpesvirus gB proteins, which is composed of β-sheets, domain IV of GP64 is a loop region; the same domain in thogotovirus glycoproteins has not been solved. In addition, domain IV is proximal to domain I (fusion domain) in prefusion structures of vesicular stomatitis virus (VSV) G and human cytomegalovirus (HCMV) gB but resides at the domain I-distal end of the molecule in a postfusion conformation. In this study, we identified that highly conserved residues and contacts within domain IV of AcMNPV GP64 are necessary for low-pH-triggered conformational change and fusion pore expansion. Our results highlight the roles of domain IV of class III viral fusion proteins in refolding during membrane fusion.
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Hodgson JJ, Buchon N, Blissard GW. Identification of insect genes involved in baculovirus AcMNPV entry into insect cells. Virology 2019; 527:1-11. [PMID: 30445201 DOI: 10.1016/j.virol.2018.10.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/19/2018] [Accepted: 10/21/2018] [Indexed: 01/01/2023]
Abstract
The baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a model enveloped DNA virus that infects and replicates in lepidopteran insect cells, and can efficiently enter a wide variety of non-host cells. Budded virions of AcMNPV enter cells by endocytosis and traffic to the nucleus where the virus initiates gene expression and genome replication. While trafficking of nucleocapsids by actin propulsion has been studied in detail, other important components of trafficking during entry remain poorly understood. We used a recombinant AcMNPV virus expressing an EGFP reporter in combination with an RNAi screen in Drosophila DL1 cells, to identify host proteins involved in AcMNPV entry. The RNAi screen targeted 86 genes involved in vesicular trafficking, including genes coding for VPS and ESCRT proteins, Rab GTPases, Exocyst proteins, and Clathrin adaptor proteins. We identified 24 genes required for efficient virus entry and reporter expression, and 4 genes that appear to restrict virus entry.
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Affiliation(s)
- Jeffrey J Hodgson
- Boyce Thompson Institute at Cornell University, Tower Road, Ithaca, NY 14853, USA.
| | - Nicolas Buchon
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA.
| | - Gary W Blissard
- Boyce Thompson Institute at Cornell University, Tower Road, Ithaca, NY 14853, USA.
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Abstract
Baculoviruses are large DNA viruses of insects that are highly pathogenic in many hosts. In the infection cycle, baculoviruses produce two types of virions. These virion phenotypes are physically and functionally distinct, and each serves a critical role in the biology of the virus. One phenotype, the occlusion-derived virus (ODV), is occluded within a crystallized protein that facilitates oral infection of the host. A large complex of at least nine ODV envelope proteins called per os infectivity factors are critically important for ODV infection of insect midgut epithelial cells. Viral egress from midgut cells is by budding to produce a second virus phenotype, the budded virus (BV). BV binds, enters, and replicates in most other tissues of the host insect. Cell recognition and entry by BV are mediated by a single major envelope glycoprotein: GP64 in some baculoviruses and F in others. Entry and egress by the two virion phenotypes occur by dramatically different mechanisms and reflect a life cycle in which ODV is specifically adapted for oral infection while BV mediates dissemination of the infection within the animal.
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Affiliation(s)
- Gary W Blissard
- Boyce Thompson Institute at Cornell University, Ithaca, New York 14853, USA;
| | - David A Theilmann
- Summerland Research and Development Center, Agriculture and Agri-Food Canada, Summerland, British Columbia V0H 1Z0, Canada;
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Feng M, Kong X, Zhang J, Xu W, Wu X. Identification of a novel host protein SINAL10 interacting with GP64 and its role in Bombyx mori nucleopolyhedrovirus infection. Virus Res 2018; 247:102-110. [DOI: 10.1016/j.virusres.2018.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/16/2022]
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13
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Sinn PL, Hwang BY, Li N, Ortiz JLS, Shirazi E, Parekh KR, Cooney AL, Schaffer DV, McCray PB. Novel GP64 envelope variants for improved delivery to human airway epithelial cells. Gene Ther 2017; 24:674-679. [PMID: 28880020 DOI: 10.1038/gt.2017.78] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/28/2017] [Accepted: 07/05/2017] [Indexed: 01/19/2023]
Abstract
Lentiviral vectors pseudotyped with the baculovirus envelope protein GP64 transduce primary cultures of human airway epithelia (HAE) at their apical surface. Our goal in this study was to harness a directed evolution approach to develop a novel envelope glycoprotein with increased transduction properties for HAE. Using error-prone PCR, a library of GP64 mutants was generated and used to prepare a diverse pool of lentiviral virions pseudotyped with GP64 variants. The library was serially passaged on HAE and three GP64 mutations were recovered. Single-, double- and the triple-combination mutant envelope glycoproteins were compared with wild-type GP64 for their ability to transduce HAE. Our results suggest that lentiviral vectors pseudotyped with evolved GP64 transduced HAE with greater efficiency than wild-type GP64. This effect was not observed in primary cultures of porcine airway epithelial cells, suggesting that the directed evolution protocol was species specific. In summary, our studies indicate that serial passage of a GP64 mutant library yielded specific variants with improved HAE cell tropism, yielding tools with the potential to improve the success of gene therapy for airway diseases.
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Affiliation(s)
- P L Sinn
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Pappajohn Biomedical Institute and the Center for Gene Therapy of Cystic Fibrosis and Other Genetic Diseases, University of Iowa, Iowa City, IA, USA
| | - B-Y Hwang
- Departments of Chemical and Biomolecular Engineering, Bioengineering, The Helen Wills Neuroscience Institute, Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA, USA
| | - N Li
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Pappajohn Biomedical Institute and the Center for Gene Therapy of Cystic Fibrosis and Other Genetic Diseases, University of Iowa, Iowa City, IA, USA
| | - J L S Ortiz
- Departments of Chemical and Biomolecular Engineering, Bioengineering, The Helen Wills Neuroscience Institute, Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA, USA
| | - E Shirazi
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - K R Parekh
- Department of Surgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - A L Cooney
- Pappajohn Biomedical Institute and the Center for Gene Therapy of Cystic Fibrosis and Other Genetic Diseases, University of Iowa, Iowa City, IA, USA.,Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - D V Schaffer
- Departments of Chemical and Biomolecular Engineering, Bioengineering, The Helen Wills Neuroscience Institute, Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA, USA
| | - P B McCray
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Pappajohn Biomedical Institute and the Center for Gene Therapy of Cystic Fibrosis and Other Genetic Diseases, University of Iowa, Iowa City, IA, USA.,Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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14
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Dong XL, Wu YF, Liu TH, Wang W, Pan CX, Adur M, Zhang MJ, Pan MH, Lu C. Bombyx mori protein BmREEPa and BmPtchd could form a complex with BmNPV envelope protein GP64. Biochem Biophys Res Commun 2017; 490:1254-1259. [DOI: 10.1016/j.bbrc.2017.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/02/2017] [Indexed: 11/24/2022]
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15
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AcMNPV-BmK IT improves the progeny virus production via baculovirus GP64 envelope fusion protein. Biotechnol Lett 2016; 38:1673-81. [DOI: 10.1007/s10529-016-2146-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/07/2016] [Indexed: 10/21/2022]
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16
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Dong XL, Liu TH, Wang W, Pan CX, Wu YF, Du GY, Chen P, Lu C, Pan MH. BmREEPa Is a Novel Gene that Facilitates BmNPV Entry into Silkworm Cells. PLoS One 2015; 10:e0144575. [PMID: 26656276 PMCID: PMC4681539 DOI: 10.1371/journal.pone.0144575] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/22/2015] [Indexed: 11/26/2022] Open
Abstract
We previously established two silkworm cell lines, BmN-SWU1 and BmN-SWU2, from Bombyx mori ovaries. BmN-SWU1 cells are susceptible while BmN-SWU2 cells are highly resistant to BmNPV infection. Interestingly, we found that the entry of BmNPV into BmN-SWU2 cells was largely inhibited. To explore the mechanism of this inhibition, in this study we used isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative protein expression profiling and identified 629 differentially expressed proteins between the two cell lines. Among them, we identified a new membrane protein termed BmREEPa. The gene encoding BmREEPa transcribes two splice variants; a 573 bp long BmREEPa-L encoding a protein with 190 amino acids and a 501 bp long BmREEPa-S encoding a protein with 166 amino acids. BmREEPa contains a conserved TB2/DP, HVA22 domain and three transmembrane domains. It is localized in the plasma membrane with a cytoplasmic C-terminus and an extracellular N-terminus. We found that limiting the expression of BmREEPa in BmN-SWU1 cells inhibited BmNPV entry, whereas over-expression of BmREEPa in BmN-SWU2 cells promoted BmNPV entry. Our results also indicated that BmREEPa can interact with GP64, which is the key envelope fusion protein for BmNPV entry. Taken together, the findings of our study revealed that BmREEPa is required for BmNPV to gain entry into silkworm cells, and may provide insights for the identification of BmNPV receptors.
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Affiliation(s)
- Xiao-long Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Tai-hang Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Wei Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Cai-xia Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Yun-fei Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Guo-yu Du
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Peng Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
- * E-mail: (M-HP); (CL)
| | - Min-hui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
- * E-mail: (M-HP); (CL)
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17
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Yu Q, Blissard GW, Liu TX, Li Z. Autographa californica multiple nucleopolyhedrovirus GP64 protein: Analysis of domain I and V amino acid interactions and membrane fusion activity. Virology 2015; 488:259-70. [PMID: 26655244 DOI: 10.1016/j.virol.2015.11.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 08/20/2015] [Accepted: 11/23/2015] [Indexed: 11/30/2022]
Abstract
The Autographa californica multiple nucleopolyhedrovirus GP64 is a class III viral fusion protein. Although the post-fusion structure of GP64 has been solved, its pre-fusion structure and the detailed mechanism of conformational change are unknown. In GP64, domain V is predicted to interact with two domain I segments that flank fusion loop 2. To evaluate the significance of the amino acids involved in these interactions, we examined 24 amino acid positions that represent interacting and conserved residues within domains I and V. In several cases, substitution of a single amino acid involved in a predicted interaction disrupted membrane fusion activity, but no single amino acid pair appears to be absolutely required. We identified 4 critical residues in domain V (G438, W439, T452, and T456) that are important for membrane fusion, and two residues (G438 and W439) that appear to be important for formation or stability of the pre-fusion conformation of GP64.
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Affiliation(s)
- Qianlong Yu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Northwest Loess Plateau Crop Pest Management of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Gary W Blissard
- Boyce Thompson Institute, Cornell University, Ithaca, NY 14853, United State
| | - Tong-Xian Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Northwest Loess Plateau Crop Pest Management of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Zhaofei Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Northwest Loess Plateau Crop Pest Management of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.
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18
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Recent mechanistic and structural insights on class III viral fusion glycoproteins. Curr Opin Struct Biol 2015; 33:52-60. [DOI: 10.1016/j.sbi.2015.07.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 07/03/2015] [Accepted: 07/24/2015] [Indexed: 01/16/2023]
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19
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Cyclic avian mass mortality in the northeastern United States is associated with a novel orthomyxovirus. J Virol 2014; 89:1389-403. [PMID: 25392223 DOI: 10.1128/jvi.02019-14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Since 1998, cyclic mortality events in common eiders (Somateria mollissima), numbering in the hundreds to thousands of dead birds, have been documented along the coast of Cape Cod, MA, USA. Although longitudinal disease investigations have uncovered potential contributing factors responsible for these outbreaks, detecting a primary etiological agent has proven enigmatic. Here, we identify a novel orthomyxovirus, tentatively named Wellfleet Bay virus (WFBV), as a potential causative agent of these outbreaks. Genomic analysis of WFBV revealed that it is most closely related to members of the Quaranjavirus genus within the family Orthomyxoviridae. Similar to other members of the genus, WFBV contains an alphabaculovirus gp64-like glycoprotein that was demonstrated to have fusion activity; this also tentatively suggests that ticks (and/or insects) may vector the virus in nature. However, in addition to the six RNA segments encoding the prototypical structural proteins identified in other quaranjaviruses, a previously unknown RNA segment (segment 7) encoding a novel protein designated VP7 was discovered in WFBV. Although WFBV shows low to moderate levels of sequence similarity to Quaranfil virus and Johnston Atoll virus, the original members of the Quaranjavirus genus, additional antigenic and genetic analyses demonstrated that it is closely related to the recently identified Cygnet River virus (CyRV) from South Australia, suggesting that WFBV and CyRV may be geographic variants of the same virus. Although the identification of WFBV in part may resolve the enigma of these mass mortality events, the details of the ecology and epidemiology of the virus remain to be determined. IMPORTANCE The emergence or reemergence of viral pathogens resulting in large-scale outbreaks of disease in humans and/or animals is one of the most important challenges facing biomedicine. For example, understanding how orthomyxoviruses such as novel influenza A virus reassortants and/or mutants emerge to cause epidemic or pandemic disease is at the forefront of current global health concerns. Here, we describe the emergence of a novel orthomyxovirus, Wellfleet Bay virus (WFBV), which has been associated with cyclic large-scale bird die-offs in the northeastern United States. This initial characterization study provides a foundation for further research into the evolution, epidemiology, and ecology of newly emerging orthomyxoviruses, such as WFBV, and their potential impacts on animal and/or human health.
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20
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Luz-Madrigal A, Asanov A, Camacho-Zarco AR, Sampieri A, Vaca L. A cholesterol recognition amino acid consensus domain in GP64 fusion protein facilitates anchoring of baculovirus to mammalian cells. J Virol 2013; 87:11894-907. [PMID: 23986592 PMCID: PMC3807332 DOI: 10.1128/jvi.01356-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/22/2013] [Indexed: 02/07/2023] Open
Abstract
Baculoviridae is a large family of double-stranded DNA viruses that selectively infect insects. Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is the best-studied baculovirus from the family. Many studies over the last several years have shown that AcMNPV can enter a wide variety of mammalian cells and deliver genetic material for foreign gene expression. While most animal viruses studied so far have developed sophisticated mechanisms to selectively infect specific cells and tissues in an organism, AcMNPV can penetrate and deliver foreign genes into most cells studied to this date. The details about the mechanisms of internalization have been partially described. In the present study, we have identified a cholesterol recognition amino acid consensus (CRAC) domain present in the AcMNPV envelope fusion protein GP64. We demonstrated the association of a CRAC domain with cholesterol, which is important to facilitate the anchoring of the virus at the mammalian cell membrane. Furthermore, this initial anchoring favors AcMNPV endocytosis via a dynamin- and clathrin-dependent mechanism. Under these conditions, efficient baculovirus-driven gene expression is obtained. In contrast, when cholesterol is reduced from the plasma membrane, AcMNPV enters the cell via a dynamin- and clathrin-independent mechanism. The result of using this alternative internalization pathway is a reduced level of baculovirus-driven gene expression. This study is the first to document the importance of a novel CRAC domain in GP64 and its role in modulating gene delivery in AcMNPV.
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Affiliation(s)
- Agustin Luz-Madrigal
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, Ohio, USA
- Department of Zoology, Miami University, Oxford, Ohio, USA
| | | | - Aldo R. Camacho-Zarco
- Max Planck Institute for Biophysical Chemistry, Protein Structure Determination, Göttingen, Germany
| | - Alicia Sampieri
- Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Distrito Federal, Mexico
| | - Luis Vaca
- Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Distrito Federal, Mexico
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