title: Three-dimensional analysis of ribonucleoprotein complexes in influenza A virus.
abstract: The influenza A virus genome consists of eight single-stranded negative-sense RNA (vRNA) segments. Although genome segmentation provides advantages such as genetic reassortment, which contributes to the emergence of novel strains with pandemic potential, it complicates the genome packaging of progeny virions. Here we elucidate, using electron tomography, the three-dimensional structure of ribonucleoprotein complexes (RNPs) within progeny virions. Each virion is packed with eight well-organized RNPs that possess rod-like structures of different lengths. Multiple interactions are found among the RNPs. The position of the eight RNPs is not consistent among virions, but a pattern suggests the existence of a specific mechanism for assembly of these RNPs. Analyses of budding progeny virions suggest two independent roles for the viral spike proteins: RNP association on the plasma membrane and the subsequent formation of the virion shell. Our data provide further insights into the mechanisms responsible for segmented-genome packaging into virions.
authors.affiliation: Department of Special Pathogens, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan. t-noda@ims.u-tokyo.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Noda
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Sugita
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Aoyama
authors.forename: Ai
authors.initials: A
authors.lastname: Hirase
authors.forename: Eiryo
authors.initials: E
authors.lastname: Kawakami
authors.forename: Atsuo
authors.initials: A
authors.lastname: Miyazawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sagara
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawaoka
mesh_terms: D000818:Animals; D002460:Cell Line; D004285:Dogs; D016678:Genome; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D009980:Influenza A virus / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D011336:Probability; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry* / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism; D014771:Virion / Q000235:genetics / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D012367:RNA, Viral; D012261:Ribonucleoproteins; D014764:Viral Proteins