Structural analysis of the roles of influenza A virus membrane-associated proteins in assembly and morphology

Chlanda, Petr, Schraidt, Oliver, Kummer, Susann, Riches, James, Oberwinkler, Heike, Prinz, Simone, Kräusslich, Hans-Georg, Briggs, John A.G., & (2015) Structural analysis of the roles of influenza A virus membrane-associated proteins in assembly and morphology. Journal of Virology, 89(17), pp. 8957-8966.

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The assembly of influenza A virus at the plasma membrane of infected cells leads to release of enveloped virions that are typically round in tissue culture-adapted strains but filamentous in strains isolated from patients. The viral proteins hemagglutinin (HA), neuraminidase (NA), matrix protein 1 (M1), and M2 ion channel all contribute to virus assembly. When expressed individually or in combination in cells, they can all, under certain conditions, mediate release of membrane-enveloped particles, but their relative roles in virus assembly, release, and morphology remain unclear. To investigate these roles, we produced membrane-enveloped particles by plasmid-derived expression of combinations of HA, NA, and M proteins (M1 and M2) or by infection with influenza A virus. We monitored particle release, particle morphology, and plasma membrane morphology by using biochemical methods, electron microscopy, electron tomography, and cryo-electron tomography. Our data suggest that HA, NA, or HANA (HA plus NA) expression leads to particle release through nonspecific induction of membrane curvature. In contrast, coexpression with the M proteins clusters the glycoproteins into filamentous membrane protrusions, which can be released as particles by formation of a constricted neck at the base. HA and NA are preferentially distributed to differently curved membranes within these particles. Both the budding intermediates and the released particles are morphologically similar to those produced during infection with influenza A virus. Together, our data provide new insights into influenza virus assembly and show that the M segment together with either of the glycoproteins is the minimal requirement to assemble and release membrane-enveloped particles that are truly virus-like.

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11 citations in Web of Science®
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ID Code: 94938
Item Type: Journal Article
Refereed: Yes
Keywords: Influenza, cryo electron tomography
DOI: 10.1128/JVI.00592-15
ISSN: 1098-5514
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > MICROBIOLOGY (060500) > Virology (060506)
Divisions: Current > Schools > School of Earth, Environmental & Biological Sciences
Current > Institutes > Institute for Future Environments
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Deposited On: 18 Apr 2016 00:44
Last Modified: 18 Apr 2016 22:20

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