The interactomes of influenza virus NS1 and NS2 proteins identify new host factors and provide insights for ADAR1 playing a supportive role in virus replication

PLoS Pathog. 2013;9(7):e1003440. doi: 10.1371/journal.ppat.1003440. Epub 2013 Jul 4.

Abstract

Influenza A NS1 and NS2 proteins are encoded by the RNA segment 8 of the viral genome. NS1 is a multifunctional protein and a virulence factor while NS2 is involved in nuclear export of viral ribonucleoprotein complexes. A yeast two-hybrid screening strategy was used to identify host factors supporting NS1 and NS2 functions. More than 560 interactions between 79 cellular proteins and NS1 and NS2 proteins from 9 different influenza virus strains have been identified. These interacting proteins are potentially involved in each step of the infectious process and their contribution to viral replication was tested by RNA interference. Validation of the relevance of these host cell proteins for the viral replication cycle revealed that 7 of the 79 NS1 and/or NS2-interacting proteins positively or negatively controlled virus replication. One of the main factors targeted by NS1 of all virus strains was double-stranded RNA binding domain protein family. In particular, adenosine deaminase acting on RNA 1 (ADAR1) appeared as a pro-viral host factor whose expression is necessary for optimal viral protein synthesis and replication. Surprisingly, ADAR1 also appeared as a pro-viral host factor for dengue virus replication and directly interacted with the viral NS3 protein. ADAR1 editing activity was enhanced by both viruses through dengue virus NS3 and influenza virus NS1 proteins, suggesting a similar virus-host co-evolution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Deaminase / chemistry
  • Adenosine Deaminase / genetics
  • Adenosine Deaminase / metabolism*
  • Biological Transport
  • Cell Line
  • Dengue Virus / enzymology
  • Host-Pathogen Interactions*
  • Humans
  • Influenza A Virus, H1N1 Subtype / physiology
  • Influenza A virus / physiology*
  • Influenza, Human / metabolism
  • Influenza, Human / pathology
  • Influenza, Human / virology
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • Recombinant Proteins / metabolism
  • Respiratory Mucosa / metabolism
  • Respiratory Mucosa / pathology
  • Respiratory Mucosa / virology
  • Ribonucleoproteins / genetics
  • Ribonucleoproteins / metabolism
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism
  • Species Specificity
  • Two-Hybrid System Techniques
  • Viral Nonstructural Proteins / genetics
  • Viral Nonstructural Proteins / metabolism*
  • Virulence Factors / genetics
  • Virulence Factors / metabolism*
  • Virus Replication*

Substances

  • INS1 protein, influenza virus
  • NS2 protein, influenza virus A
  • RNA-Binding Proteins
  • Recombinant Proteins
  • Ribonucleoproteins
  • Viral Nonstructural Proteins
  • Virulence Factors
  • NS3 protease, dengue virus
  • Serine Endopeptidases
  • ADARB1 protein, human
  • Adenosine Deaminase

Grants and funding

This work was funded by ANR, ANRS, Inserm and the FUI from the French Ministry of Industry. RB was supported by the Deutsche Forschungsgemeinschaft (FOR1202, TP1). RB and VL are also supported by the European Union's 7th program (FP7/2007-2013) under grant agreement no 267429 (SysPatho). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.