A double-stranded RNA platform is required for the interaction between a host restriction factor and the NS1 protein of influenza A virus

Nucleic Acids Res. 2020 Jan 10;48(1):304-315. doi: 10.1093/nar/gkz1094.


Influenza A viruses cause widespread human respiratory disease. The viral multifunctional NS1 protein inhibits host antiviral responses. This inhibition results from the binding of specific cellular antiviral proteins at various positions on the NS1 protein. Remarkably, binding of several proteins also requires the two amino-acid residues in the NS1 N-terminal RNA-binding domain (RBD) that are required for binding double-stranded RNA (dsRNA). Here we focus on the host restriction factor DHX30 helicase that is countered by the NS1 protein, and establish why the dsRNA-binding activity of NS1 is required for its binding to DHX30. We show that the N-terminal 152 amino-acid residue segment of DHX30, denoted DHX30N, possesses all the antiviral activity of DHX30 and contains a dsRNA-binding domain, and that the NS1-DHX30 interaction in vivo requires the dsRNA-binding activity of both DHX30N and the NS1 RBD. We demonstrate why this is the case using bacteria-expressed proteins: the DHX30N-NS1 RBD interaction in vitro requires the presence of a dsRNA platform that binds both NS1 RBD and DHX30N. We propose that a similar dsRNA platform functions in interactions of the NS1 protein with other proteins that requires these same two amino-acid residues required for NS1 RBD dsRNA-binding activity.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Binding Sites
  • Cloning, Molecular
  • Dogs
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Host-Pathogen Interactions / genetics*
  • Humans
  • Madin Darby Canine Kidney Cells
  • Models, Molecular
  • Nucleic Acid Conformation
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Interaction Domains and Motifs
  • RNA Helicases / chemistry
  • RNA Helicases / genetics*
  • RNA Helicases / metabolism
  • RNA, Double-Stranded / chemistry
  • RNA, Double-Stranded / genetics*
  • RNA, Double-Stranded / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Signal Transduction
  • Viral Nonstructural Proteins / chemistry
  • Viral Nonstructural Proteins / genetics*
  • Viral Nonstructural Proteins / metabolism


  • INS1 protein, influenza virus
  • RNA, Double-Stranded
  • Recombinant Proteins
  • Viral Nonstructural Proteins
  • DHX30 protein, human
  • RNA Helicases