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

摘要: The assembly of influenza A virus at the plasma membrane infected cells leads to release enveloped virions that are typically round in tissue culture-adapted strains but filamentous isolated from patients. viral proteins hemagglutinin (HA), neuraminidase (NA), matrix protein 1 (M1), and M2 ion channel all contribute assembly. When expressed individually or combination cells, they can all, under certain conditions, mediate membrane-enveloped particles, their relative roles assembly, release, morphology remain unclear. To investigate these roles, we produced particles by plasmid-derived expression combinations HA, NA, M (M1 M2) infection with virus. We monitored particle morphology, using biochemical methods, electron microscopy, tomography, cryo-electron tomography. Our data suggest HANA (HA plus NA) through nonspecific induction curvature. In contrast, coexpression clusters glycoproteins into protrusions, which be released as formation a constricted neck base. HA NA preferentially distributed differently curved membranes within particles. Both budding intermediates morphologically similar those during Together, our provide new insights show segment together either is minimal requirement assemble truly virus-like. IMPORTANCE Influenza major respiratory pathogen. It assembles whose shapes vary spherical filamentous. Here examine individual mediating determining shape. do this, used range microscopy techniques obtain compare two- three-dimensional images virus-like after were different proteins. Among results, found one both surface (hemagglutinin neuraminidase) membrane-associated encoded results manner very virions. These novel played