1. Microbiology and Infectious Disease
Download icon

pp32 and APRIL are host cell-derived regulators of influenza virus RNA synthesis from cRNA

  1. Kenji Sugiyama
  2. Atsushi Kawaguchi
  3. Mitsuru Okuwaki
  4. Kyosuke Nagata  Is a corresponding author
  1. University of Tsukuba, Japan
Research Article
  • Cited 41
  • Views 2,322
  • Annotations
Cite this article as: eLife 2015;4:e08939 doi: 10.7554/eLife.08939

Abstract

Replication of influenza viral genomic RNA (vRNA) is catalyzed by viral RNA-dependent RNA polymerase (vRdRP). Complementary RNA (cRNA) is first copied from vRNA, and progeny vRNAs are then amplified from the cRNA. Although vRdRP and viral RNA are minimal requirements, efficient cell-free replication could not be reproduced using only these viral factors. Using a biochemical complementation assay system, we found a novel activity in the nuclear extracts of uninfected cells, designated IREF-2, that allows robust unprimed vRNA synthesis from a cRNA template. IREF-2 was shown to consist of host-derived proteins, pp32 and APRIL. IREF-2 interacts with a free form of vRdRP and preferentially upregulates vRNA synthesis rather than cRNA synthesis. Knockdown experiments indicated that IREF-2 is involved in in vivo viral replication. On the basis of these results and those of previous studies, a plausible role(s) for IREF-2 during the initiation processes of vRNA replication is discussed.

Article and author information

Author details

  1. Kenji Sugiyama

    Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
    Competing interests
    The authors declare that no competing interests exist.

  2. Atsushi Kawaguchi

    Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
    Competing interests
    The authors declare that no competing interests exist.

  3. Mitsuru Okuwaki

    Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
    Competing interests
    The authors declare that no competing interests exist.

  4. Kyosuke Nagata

    Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
    For correspondence
    knagata@md.tsukuba.ac.jp
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Stephen P Goff, Howard Hughes Medical Institute, Columbia University, United States

Publication history

  1. Received: May 26, 2015
  2. Accepted: October 20, 2015
  3. Accepted Manuscript published: October 29, 2015 (version 1)
  4. Version of Record published: January 7, 2016 (version 2)
  5. Version of Record updated: February 21, 2017 (version 3)

Copyright

© 2015, Sugiyama et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 2,322
    Page views
  • 608
    Downloads
  • 41
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, Scopus, PubMed Central.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Categories and tags

Research organism

Further reading

    1. Biochemistry and Chemical Biology
    2. Microbiology and Infectious Disease

    Glycine acylation and trafficking of a new class of bacterial lipoprotein by a composite secretion system

    Christopher Icke et al.
    Research Article

    Protein acylation is critical for many cellular functions across all domains of life. In bacteria, lipoproteins have important roles in virulence and are targets for the development of antimicrobials and vaccines. Bacterial lipoproteins are secreted from the cytosol via the Sec pathway and acylated on an N-terminal cysteine residue through the action of three enzymes. In Gram-negative bacteria, the Lol pathway transports lipoproteins to the outer membrane. Here we demonstrate that the Aat secretion system is a composite system sharing similarity with elements of a type I secretion systems and the Lol pathway. During secretion, the AatD subunit acylates the substrate CexE on a highly conserved N-terminal glycine residue. Mutations disrupting glycine acylation interfere with membrane incorporation and trafficking. Our data reveal CexE as the first member of a new class of glycine-acylated lipoprotein, while Aat represents a new secretion system that displays the substrate lipoprotein on the cell surface.

    1. Genetics and Genomics
    2. Microbiology and Infectious Disease

    An interbacterial DNA deaminase toxin directly mutagenizes surviving target populations

    Marcos H de Moraes et al.
    Research Article Updated

    When bacterial cells come in contact, antagonism mediated by the delivery of toxins frequently ensues. The potential for such encounters to have long-term beneficial consequences in recipient cells has not been investigated. Here, we examined the effects of intoxication by DddA, a cytosine deaminase delivered via the type VI secretion system (T6SS) of Burkholderia cenocepacia. Despite its killing potential, we observed that several bacterial species resist DddA and instead accumulate mutations. These mutations can lead to the acquisition of antibiotic resistance, indicating that even in the absence of killing, interbacterial antagonism can have profound consequences on target populations. Investigation of additional toxins from the deaminase superfamily revealed that mutagenic activity is a common feature of these proteins, including a representative we show targets single-stranded DNA and displays a markedly divergent structure. Our findings suggest that a surprising consequence of antagonistic interactions between bacteria could be the promotion of adaptation via the action of directly mutagenic toxins.

    1. Genetics and Genomics
    2. Microbiology and Infectious Disease

    Bacterial Warfare: Toxins, mutations and adaptations

    Maarten De Jong, Neal M Alto
    Insight

    The toxins that some bacteria secrete to kill off rival species can also generate mutations that help toxin-resistant populations adapt to new environments.