Structural dissection of Ebola virus and its assembly determinants using cryo-electron tomography

Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 02/2012; 109(11):4275-80. DOI: 10.1073/pnas.1120453109
Source: PubMed


Ebola virus is a highly pathogenic filovirus causing severe hemorrhagic fever with high mortality rates. It assembles heterogenous, filamentous, enveloped virus particles containing a negative-sense, single-stranded RNA genome packaged within a helical nucleocapsid (NC). We have used cryo-electron microscopy and tomography to visualize Ebola virus particles, as well as Ebola virus-like particles, in three dimensions in a near-native state. The NC within the virion forms a left-handed helix with an inner nucleoprotein layer decorated with protruding arms composed of VP24 and VP35. A comparison with the closely related Marburg virus shows that the N-terminal region of nucleoprotein defines the inner diameter of the Ebola virus NC, whereas the RNA genome defines its length. Binding of the nucleoprotein to RNA can assemble a loosely coiled NC-like structure; the loose coil can be condensed by binding of the viral matrix protein VP40 to the C terminus of the nucleoprotein, and rigidified by binding of VP24 and VP35 to alternate copies of the nucleoprotein. Four proteins (NP, VP24, VP35, and VP40) are necessary and sufficient to mediate assembly of an NC with structure, symmetry, variability, and flexibility indistinguishable from that in Ebola virus particles released from infected cells. Together these data provide a structural and architectural description of Ebola virus and define the roles of viral proteins in its structure and assembly.

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    • "Although the KZ52 protection test on NHPs was unsuccessful, experiments on this antibody have led to the conclusion that the GP1 and GP2 interface, rather than the hyperglycosylated head of GP trimer, could be a target for neutralizing antibody design. Electron microscope images show that the whole, long virions are thickly coated by the GP trimers [21], indicating that a group of antibodies might be used compositionally to efficiently inhibit all GP trimers. "
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    ABSTRACT: Ebola virus infection can cause Ebola virus disease (EVD). Patients usually show severe symptoms, and the fatality rate can reach up to 90%. No licensed medicine is available. In this review, development of therapeutics for treatment of Ebola virus infection and EVD will be discussed. Copyright © 2014. Published by Elsevier Masson SAS.
    Microbes and Infection 12/2014; 17(2). DOI:10.1016/j.micinf.2014.11.012 · 2.86 Impact Factor
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    • "Although some RT-PCR detection techniques have been developed to screen for Ebola virus and Marburg virus (Huang Y, et al., 2012), no filovirus-specific antibody-based indirect enzyme-linked immunosorbent assays (indirect ELISAs) for serological diagnosis are available in China. Filovirus nucleoprotein may be the ideal target antigen because of its abundance in filovirus particles and its strong antigenicity (Niikura M, et al., 2001, 2003; Bharat T, et al., 2012). Nucleoprotein consists of 739 or 695 amino acid residues, with a conserved hydrophobic N-terminus and a variable hydrophilic C-terminal part (Niikura M, et al., 2001; Sanchez A, et al., 2007; LÖtfering B, et al., 1999). "
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    ABSTRACT: Full-length nucleoproteins from Ebola and Marburg viruses were expressed as His-tagged recombinant proteins in Escherichia coli and nucleoprotein-based enzyme-linked immunosorbent assays (ELISAs) were established for the detection of antibodies specific to Ebola and Marburg viruses. The ELISAs were evaluated by testing antisera collected from rabbit immunized with Ebola and Marburg virus nucleoproteins. Although little cross-reactivity of antibodies was observed in anti-Ebola virus nucleoprotein rabbit antisera, the highest reactions to immunoglobulin G (IgG) were uniformly detected against the nucleoprotein antigens of homologous viruses. We further evaluated the ELISA's ability to detect antibodies to Ebola and Marburg viruses using human sera samples collected from individuals passing through the Guangdong port of entry. With a threshold set at the mean plus three standard deviations of average optical densities of sera tested, the ELISA systems using these two recombinant nucleoproteins have good sensitivity and specificity. These results demonstrate the usefulness of ELISA for diagnostics as well as ecological and serosurvey studies of Ebola and Marburg virus infection.
    Virologica Sinica 12/2014; 29(6):372-80. DOI:10.1007/s12250-014-3512-0
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    • "Filoviruses are of concern because they cause hemorrhagic fever with a high fatality rate in humans (reviewed in Brauburger et al., 2012). Filoviruses encode multifunctional VP24 proteins, which play important roles in the formation of viral nucleocapsids, release of infectious virus particles, and modulation of viral RNA synthesis (Bamberg et al., 2005; Beniac et al., 2012; Bharat et al., 2011, 2012; Hoenen et al., 2006; Huang et al., 2002; Mateo et al., 2011; Noda et al., 2006; Watanabe et al., 2007; Wenigenrath et al., 2010). In addition, EBOV VP24 (eVP24) disrupts interferon (IFN) signaling pathways and interacts with select karyopherin a proteins (KPNAs), thereby blocking nuclear accumulation of tyrosine-phosphorylated STAT1 (Mateo et al., 2010; Reid et al., 2006, 2007). "
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