Architecture of ribonucleoprotein complexes in influenza A virus particles

University of California, Davis, Davis, California, United States
Nature (Impact Factor: 41.46). 02/2006; 439(7075):490-2. DOI: 10.1038/nature04378
Source: PubMed


In viruses, as in eukaryotes, elaborate mechanisms have evolved to protect the genome and to ensure its timely replication and reliable transmission to progeny. Influenza A viruses are enveloped, spherical or filamentous structures, ranging from 80 to 120 nm in diameter. Inside each envelope is a viral genome consisting of eight single-stranded negative-sense RNA segments of 890 to 2,341 nucleotides each. These segments are associated with nucleoprotein and three polymerase subunits, designated PA, PB1 and PB2; the resultant ribonucleoprotein complexes (RNPs) resemble a twisted rod (10-15 nm in width and 30-120 nm in length) that is folded back and coiled on itself. Late in viral infection, newly synthesized RNPs are transported from the nucleus to the plasma membrane, where they are incorporated into progeny virions capable of infecting other cells. Here we show, by transmission electron microscopy of serially sectioned virions, that the RNPs of influenza A virus are organized in a distinct pattern (seven segments of different lengths surrounding a central segment). The individual RNPs are suspended from the interior of the viral envelope at the distal end of the budding virion and are oriented perpendicular to the budding tip. This finding argues against random incorporation of RNPs into virions, supporting instead a model in which each segment contains specific incorporation signals that enable the RNPs to be recruited and packaged as a complete set. A selective mechanism of RNP incorporation into virions and the unique organization of the eight RNP segments may be crucial to maintaining the integrity of the viral genome during repeated cycles of replication.

Download full-text


Available from: Hiroshi Kida,
  • Source
    • "composed mostly of the NP protein, which wraps eight different RNA segments of the influenza A genome. Additionally , RNPs contain about 50 copies per virion of RNA-dependent RNA polymerase, which in case of influenza A virus is a complex of three proteins: PB1, PB2 and PA (Noda et al., 2006; Boivin et al., 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: This minireview presents an overview of current knowledge on virion structure, genome organization and basic events in the development of Influenza A virus. The processes of entry, transcription/replication and viral release are described. In this context, the roles of viral proteins (including recently discovered minor polypeptides) in the subsequent stages of viral development are also discussed.
    Acta biochimica Polonica 09/2014; 61(3). · 1.15 Impact Factor
  • Source
    • "Dimerization occurs via base-pairing of a self-complementary stem-loop structure called the dimerization initiation site, where the base-pairing starts at the loop (formation of a kissing loop complex) and extends into the stem (formation of an extended duplex). Influenza A virus (IAV) possesses an eight-segmented –RNA genome, and the IAV virion contains one copy of each genomic segment (Noda et al., 2006; Chou et al., 2012; Fournier et al., 2012). In each segment, the 5'-and 3'-terminal ~20 nucleotides form a panhandle structure via long-range interaction (LRI) (Suzuki and Kobayashi, 2013), and packaging signals are located in the terminal ~200 nucleotides including the untranslated regions (UTRs) and parts of the open reading frames (ORFs), which are segment-specific but Y. SUZUKI highly conserved (Hutchinson et al., 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Group A rotavirus (RVA), an etiological agent of gastroenteritis in young mammals and birds, possesses a genome of 11 double-stranded RNA segments. Although it is believed that the RVA virion contains one copy of each genomic segment and that the positive-strand RNA (+RNA) is incorporated into the core shell, the packaging mechanisms of RVA are not well understood. Here, packaging signals of RVA were searched for by analyzing genomic sequences of mammalian and avian RVA, which are considered to have evolved independently without reassortment. Assuming that packaging is mediated by direct interaction between +RNA segments via base-pairing, co-evolving complementary nucleotide sites were identified within and between genomic segments. There were two pairs of co-evolving complementary sites within the segment encoding VP7 (the VP7 segment) and one pair between the NSP2 and NSP3 segments. In the VP7 segment, the co-evolving complementary sites appeared to form stem structures in both mammalian and avian RVA, supporting their functionality. In contrast, co-evolving complementary sites between the NSP2 and NSP3 segments tended to be free from base-pairings and constituted loop structures, at least in avian RVA, suggesting that they are involved in a specific interaction between these segments as a packaging signal.
    Genes & Genetic Systems 09/2014; 89(2):81-6. DOI:10.1266/ggs.89.81 · 0.93 Impact Factor
  • Source
    • "Influenza viruses are spherical or filamentous, enveloped, and range in size from 80 to 100 nm [1]. Influenza is a pandemic disease caused by different viral strains, which emerge during seasonal changes. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Discrimination of closely related strains is a key issue, particularly for infectious diseases whose incidence fluctuates according to variations in the season and evolutionary changes. Among infectious diseases, influenza viral infections are a worldwide cause of pandemic disease and mortality. With the emergence of different influenza strains, it is vital to develop a method using antibodies that can differentiate between viral types and subtypes. Ideally, such a system would also be user friendly. In this study, a polyclonal antibody generated against A/Udorn/307/1972 (H3N2) was used as a probe to distinguish between influenza H3N2 viruses based on the interaction between the antibody and hemagglutinin, demonstrating its applicability for viral discrimination. Clear discrimination was demonstrated using an evanescent-field-coupled waveguide-mode sensor, which has appealing characteristics over other methods in the viewpoint of improving the sensitivity, measurement time, portability and usability. Further supporting evidence was obtained using enzyme-linked immunosorbent assays, hemagglutination-inhibition assays, and infectivity neutralization assays. The results obtained indicate that the polyclonal antibody used here is a potential probe for distinguishing influenza viruses and, with the aid of a handheld sensor it could be used for influenza surveillance.
    PLoS ONE 12/2013; 8(12):e81396. DOI:10.1371/journal.pone.0081396 · 3.23 Impact Factor
Show more