Induction of IRF-3/-7 kinase and NF-kappaB in response to double-stranded RNA and virus infection: common and unique pathways

Genes Cells. 2001 Apr;6(4):375-88. doi: 10.1046/j.1365-2443.2001.00426.x.

Abstract

Background: Infection by virus or treatment with double-stranded RNA (dsRNA) results in the activation of transcription factors including IRF-3, IRF-7 and a pleiotropic regulator NF-kappaB by specific phosphorylation. These factors are important in triggering a cascade of antiviral responses. A protein kinase that is yet to be identified is responsible for the activation of these factors and plays a key role in the responses.

Results: The signal cascade was analysed using sensitive assays for the activation of IRF-3 and NF-kappaB, and various inhibitors. We found that the activation of IRF-3 and NF-kappaB by dsRNA or virus involves a process that is sensitive to Geldanamycin. Although the induction of NF-kappaB by dsRNA/virus and TNF-alpha involves common downstream pathways including IKK activation, the upstream, Geldanamycin-sensitive process was unique to the dsRNA/virus-induced signal. By an in vitro assay using cell extract, we found an inducible protein kinase activity with physiological specificity of IRF-3 phosphorylation. Furthermore, the same extract specifically phosphorylated IRF-7 in a similar manner.

Conclusions: Double-stranded RNA or virus triggers a specific signal cascade that results in the activation of the IRF-3/-7 kinase we detected, which corresponds to the long-sought signalling machinery that is responsible for triggering the early phase of innate response. The signal branches to a common NF-kappaB activation cascade, thus resulting in the activation of a set of critical transcription factors for the response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoquinones
  • DNA-Binding Proteins / antagonists & inhibitors
  • DNA-Binding Proteins / biosynthesis*
  • DNA-Binding Proteins / genetics
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation / drug effects
  • Enzyme Induction
  • Enzyme-Linked Immunosorbent Assay
  • Gene Expression Regulation, Enzymologic
  • Genetic Vectors
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Interferon Regulatory Factor-3
  • Interferon Regulatory Factor-7
  • Lactams, Macrocyclic
  • NF-kappa B / biosynthesis*
  • Newcastle disease virus / metabolism*
  • Phosphorylation
  • Poly I-C / pharmacology
  • Protein-Serine-Threonine Kinases / metabolism
  • Quinones / pharmacology
  • RNA, Double-Stranded / pharmacology*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Serine Proteinase Inhibitors / pharmacology
  • Signal Transduction
  • Tosylphenylalanyl Chloromethyl Ketone / pharmacology
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / biosynthesis*
  • Transcription Factors / genetics
  • Tumor Cells, Cultured
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Benzoquinones
  • DNA-Binding Proteins
  • IRF3 protein, human
  • IRF7 protein, human
  • Interferon Regulatory Factor-3
  • Interferon Regulatory Factor-7
  • Lactams, Macrocyclic
  • NF-kappa B
  • Quinones
  • RNA, Double-Stranded
  • Recombinant Proteins
  • Serine Proteinase Inhibitors
  • Transcription Factors
  • Tumor Necrosis Factor-alpha
  • Tosylphenylalanyl Chloromethyl Ketone
  • Protein-Serine-Threonine Kinases
  • Poly I-C
  • geldanamycin