Structural organization of a filamentous influenza A virus

Calder, Lesley J.; Wasilewski, Sebastian; Berriman, John; Rosenthal, Peter B.

doi:10.1073/pnas.1002123107

Cited by 219 publications

(329 citation statements)

References 50 publications

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“…For a more detailed structural analysis, we used cryo-ET, a method of choice for 3D reconstruction of pleomorphic, membrane-containing particles (5,(18)(19)(20). In a total of 41 tomograms from three separate preparations of A2 virus collected from the cell culture supernatant, we analyzed 103 virions.…”

Section: Resultsmentioning

confidence: 99%

Architecture of respiratory syncytial virus revealed by electron cryotomography

Liljeroos

Krzyzaniak²,

Helenius³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

177

173

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Human respiratory syncytial virus is a human pathogen that causes severe infection of the respiratory tract. Current information about the structure of the virus and its interaction with host cells is limited. We carried out an electron cryotomographic characterization of cell culture-grown human respiratory syncytial virus to determine the architecture of the virion. The particles ranged from 100 nm to 1,000 nm in diameter and were spherical, filamentous, or a combination of the two. The filamentous morphology correlated with the presence of a cylindrical matrix protein layer linked to the inner leaflet of the viral envelope and with local ordering of the glycoprotein spikes. Recombinant viruses with only the fusion protein in their envelope showed that these glycoproteins were predominantly in the postfusion conformation, but some were also in the prefusion form. The ribonucleocapsids were left-handed, randomly oriented, and curved inside the virions. In filamentous particles, they were often adjacent to an intermediate layer of protein assigned to M2-1 (an envelopeassociated protein known to mediate association of ribonucleocapsids with the matrix protein). Our results indicate important differences in structure between the Paramyxovirinae and Pneumovirinae subfamilies within the Paramyxoviridae, and provide fresh insights into host cell exit of a serious pathogen.cryo-ET | paramyxovirus | virus structure H uman respiratory syncytial virus (HRSV) causes severe disease, especially in children and the elderly (1, 2). In a study covering data from 2005, it was found that HRSV was responsible for 22% of acute lower respiratory infections worldwide and 66,000-199,000 deaths in children under the age of 5 y (2). Treatment is currently limited to purine analogs (Ribavirin) and passive immune-prophylaxis with humanized monoclonal antibodies (Palivizumab) (3).RSV belongs to the Paramyxoviridae, a large family of enveloped, negative-sense RNA viruses with many members from humans and animals. Together with human metapneumovirus, it constitutes the Pneumovirinae subfamily. Like other paramyxoviruses, it has a plasma-membrane-derived lipid envelope and a helical ribonucleocapsid (RNP) that contains a single viral RNA molecule associated with nucleoproteins (N), and an RNA-dependent RNA polymerase. The virion contains, in addition, a matrix protein (M) (4-7) and a transcription antiterminator, M2-1 (an envelopeassociated protein known to mediate association of RNPs with the M protein) (8-11). The lipid envelope contains two transmembrane glycoproteins: the fusion protein, F, and a glycoprotein, G, used for attachment to host cells. In addition, HRSV contains a small hydrophobic protein, SH, of unclear function and proteins of cellular origin, such as actin and chaperones (12). The RNP and F have been analyzed using 3D-EM and X-ray crystallography (13,14).HRSV particles are pleomorphic with both spherical and filamentous particles of different sizes (15). Early electron microscopy studies showed the presence of a helical p...

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Section: Resultsmentioning

confidence: 99%

Architecture of respiratory syncytial virus revealed by electron cryotomography

Liljeroos

Krzyzaniak²,

Helenius³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

177

173

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“…We also derived density maps of HA-C179 complexes displayed on filamentous virions to address the issue of whether primary isolates and certain strains of influenza that have a more filamentous population of virions (22,(29)(30)(31) can also bind to stem antibodies in the same manner as observed for spherical H1N1 virions. Density maps and fits obtained from spikes on filamentous H1N1 virions demonstrate that C179 binds HA trimers to form complexes that are essentially the same as those seen for spherical virions (Fig.…”

Section: Resultsmentioning

confidence: 99%

Structure and accessibility of HA trimers on intact 2009 H1N1 pandemic influenza virus to stem region-specific neutralizing antibodies

Harris

Meyerson

Matsuoka³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

105

113

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Rapid antigenic variation of HA, the major virion surface protein of influenza A virus, remains the principal challenge to the development of broader and more effective vaccines. Some regions of HA, such as the stem region proximal to the viral membrane, are nevertheless highly conserved across strains and among most subtypes. A fundamental question in vaccine design is the extent to which HA stem regions on the surface of the virus are accessible to broadly neutralizing antibodies. Here we report 3D structures derived from cryoelectron tomography of HA on intact 2009 H1N1 pandemic virions in the presence and absence of the antibody C179, which neutralizes viruses expressing a broad range of HA subtypes, including H1, H2, H5, H6, and H9. By fitting previously derived crystallographic structures of trimeric HA into the density maps, we deduced the locations of the molecular surfaces of HA involved in interaction with C179. Using computational methods to distinguish individual unliganded HA trimers from those that have bound C179 antibody, we demonstrate that ∼75% of HA trimers on the surface of the virus have C179 bound to the stem domain. Thus, despite their close packing on the viral membrane, the majority of HA trimers on intact virions are available to bind anti-stem antibodies that target conserved HA epitopes, establishing the feasibility of universal influenza vaccines that elicit such antibodies.envelope glycoproteins | subvolume averaging | virus structure | hemagglutunin | cryo-electron microscopy

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“…This information is critical to define the interaction among RNPs during the encapsidation mediated by the packaging signals. The convergence of cryo-EM of viral RNPs, 34 cryo-tomography of virions 41,42 and genetic analysis of RNP packaging (reviewed in ref. 43) should provide a clearer view of the influenza genome encapsidation into infectious virus.…”

confidence: 99%