title: Architecture of respiratory syncytial virus revealed by electron cryotomography.
abstract: 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 envelope-associated 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.
authors.affiliation: Department of Biosciences and Institute of Biotechnology, University of Helsinki, FIN-00790, Helsinki, Finland.
authors.forename: Lassi
authors.initials: L
authors.lastname: Liljeroos
authors.forename: Magdalena Anna
authors.initials: MA
authors.lastname: Krzyzaniak
authors.forename: Ari
authors.initials: A
authors.lastname: Helenius
authors.forename: Sarah Jane
authors.initials: SJ
authors.lastname: Butcher
mesh_terms: D002460:Cell Line; D020285:Cryoelectron Microscopy; D055032:Electron Microscope Tomography; D006801:Humans; D011487:Protein Conformation; D018113:Respiratory Syncytial Virus, Human / Q000737:chemistry / Q000648:ultrastructure*; D012261:Ribonucleoproteins / Q000737:chemistry / Q000648:ultrastructure; D014760:Viral Fusion Proteins / Q000737:chemistry / Q000648:ultrastructure
chemical_list: C526850:F protein, human respiratory syncytial virus; D012261:Ribonucleoproteins; D014760:Viral Fusion Proteins
keywords: cryo-ET; paramyxovirus; virus structure