Complementarity in the Supramolecular Design of Arenaviruses and Retroviruses Revealed by Electron Cryomicroscopy and Image Analysis

Department of Neuropharmacology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA.
Journal of Virology (Impact Factor: 4.44). 04/2005; 79(6):3822-30. DOI: 10.1128/JVI.79.6.3822-3830.2005
Source: PubMed


Arenaviruses are rodent-borne agents of diseases, including potentially lethal human hemorrhagic fevers. These enveloped viruses
encapsidate a bisegmented ambisense single-stranded RNA genome that can be packaged in variable copy number. Electron cryomicroscopy
and image analysis of New World Pichinde and Tacaribe arenaviruses and Old World lymphocytic choriomeningitis virus revealed
pleomorphic enveloped particles ranging in diameter from ∼400 to ∼2,000 Å. The surface spikes were spaced ∼100 Å apart and
extended ∼90 Å from the maximum phospholipid headgroup density of the outer bilayer leaflet. Distinctive stalk and head regions
extended radially ∼30 and ∼60 Å from the outer bilayer leaflet, respectively. Two interior layers of density apposed to the
inner leaflet of the viral lipid bilayer were assigned as protein Z and nucleoprotein (NP) molecules on the basis of their
appearance, spacing, and projected volume. Analysis of en face views of virions lacking the GP-C spikes showed reflections
consistent with paracrystalline packing of the NP molecules in a lattice with edges of ∼57 and ∼74 Å. The structural proteins
of retroviruses and arenaviruses assemble with similar radial density distributions, using common cellular components.

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    • "Arenaviruses (genus Arenavirus, family Arenaviridae) are enveloped , single-stranded RNA viruses of ambisense polarity (Neuman et al., 2005). The virus genome comprises two segments. "
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    ABSTRACT: To determine the biodiversity of arenaviruses in China, we captured and screened rodents and shrews in Wenzhou city, Zhejiang province, a locality where hemorrhagic fever diseases are endemic in humans. Accordingly, arenaviruses were detected in 42 of 351 rodents from eight species, and in 12 of 272 Asian house shrews (Suncus murinus), by RT-PCR targeting the L segment. From these, a single arenavirus was successfully isolated in cell culture. The virion particles exhibited a typical arenavirus morphology under transmission electron microscopy. Comparison of the S and L segment sequences revealed high levels of nucleotide (>32.2% and >39.6%) and amino acid (>28.8% and >43.8%) sequence differences from known arenaviruses, suggesting that it represents a novel arenavirus, which we designated Wenzhou virus (WENV). Phylogenetic analysis revealed that all WENV strains harbored by both rodents and Asian house shrews formed a distinct lineage most closely related to Old World arenaviruses.KeywordsArenavirusRodentsShrewsSpill-overCross-species transmissionEmergence
    Full-text · Article · Dec 2014 · Virology
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    • "GPC is processed post-translationally yielding a mature glycoprotein complex formed by three subunits that remain non covanlently linked: the signal peptide SSP, the external receptor-binding GP1 and the transmembrane fusion GP2 protein [4-6]. The L segment encodes the RNA-dependent RNA polymerase L and a small protein called Z. Several lines of evidence indicate that Z is essential for viral particle assembly and release [7-10]. Indeed, like the matrix protein of other enveloped viruses, Z protein self-associates into oligomeric forms, binds to cellular membranes, displays self-budding activity and is able to mediate the incorporation of NP and the envelope viral glycoproteins into virus-like particles (VLPs) [8,9,11-14]. "
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    ABSTRACT: Several arenaviruses can cause severe hemorrhagic fever (HF) in humans, representing a public health threat in endemic areas of Africa and South America. The present study characterizes the potent virucidal activity of the carboxamide-derivatized aromatic disulfide NSC4492, an antiretroviral zinc finger-reactive compound, against Junín virus (JUNV), the causative agent of Argentine HF. The compound was able to inactivate JUNV in a time and temperature-dependent manner, producing more than 99 % reduction in virus titer upon incubation with virions at 37°C for 90 min. The ability of NSC4492-treated JUNV to go through different steps of the multiplication cycle was then evaluated. Inactivated virions were able to bind and enter into the host cell with similar efficiency as control infectious particles. In contrast, treatment with NSC4492 impaired the capacity of JUNV to drive viral RNA synthesis, as measured by quantitative RT-PCR, and blocked viral protein expression, as determined by indirect immunofluorescence. These results suggest that the disulfide NSC4492 targets on the arenavirus replication complex leading to impairment in viral RNA synthesis. Additionally, analysis of VLP produced in NSC4492-treated cells expressing JUNV matrix Z protein revealed that the compound may interact with Z resulting in an altered aggregation behavior of this protein, but without affecting its intrinsic self-budding properties. The potential perspectives of NSC4492 as an inactivating vaccinal compound for pathogenic arenaviruses are discussed.
    Full-text · Article · Nov 2013 · PLoS ONE
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    • "It comprises three main regions that contain different domains: the Amino-end (Myristoylation Domain), the Core (RING Domain), and Carboxyl-end (Late Domain) [2]. Among the several functions described for this small protein (11 kDa) it can be highlighted its inhibitory effect on viral RNA replication and transcription through its interaction with the L protein [3,4] as well as its capability of interacting and recruiting the viral nucleoprotein [5,6]. Other interesting proposed properties may include: translation inhibition through interactions with cellular factors like the promyelocytic leukemia protein (PML) [7], the eukaryotic translation initiation factor eIF4E [8], and downregulation of IRF7 expression in arenavirus-infected plasmacytoid dendritic cells (pDCs) [9]. "
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    ABSTRACT: Background Arenavirus matrix protein Z plays an important role in virus budding and is able to generate enveloped virus-like-particles (VLPs) in absence of any other viral proteins. In these VLPs, Z protein is associated to the plasma membrane inner surface by its myristoyl residue. Budding induction and vesicle formation properties can be exploited to generate enveloped VLPs platform. These structures can be designed to carry specific antigen in the inner side or on the surface of VLPs. Vaccines based on VLPs are a highly effective type of subunit vaccines that mimic the overall structure of virus particles in absence of viral nucleic acid, being noninfectious. In this work we assayed the capacity of Junin Z protein to produce VLPs carrying the green fluorescent protein (eGFP), as a model antigen. Results In this report the Junin Z protein ability to produce VLPs from 293T cells and its capacity to deliver a specific antigen (eGFP) fused to Z was evaluated. Confocal microscopy showed a particular membrane bending in cells expressing Z and a spot welded distribution in the cytoplasm. VLPs were detected by TEM (transmission electron microscopy) and were purified from cell supernatant. The proteinase protection assay demonstrated the VLPs integrity and the absence of degradation of the fused antigen, thus indicating its internal localization. Finally, immunization of mice with purified VLPs produced high titres of anti-eGFP antibodies compared to the controls. Conclusions It was proved that VLPs can be generated from cells transfected with a fusion Junin virus Z-eGFP protein in absence of any other viral protein, and the capacity of Z protein to support fusions at the C-terminal, without impairing its budding activity, allowing vehiculization of specific antigens into VLPs.
    Full-text · Article · Nov 2012 · BMC Biotechnology
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