siRNA targeting vaccinia virus double-stranded RNA binding protein [E3L] exerts potent antiviral effects

Virology. 2006 May 10;348(2):489-97. doi: 10.1016/j.virol.2006.01.013. Epub 2006 Feb 9.


The Vaccinia virus gene, E3L, encodes a double-stranded RNA [dsRNA]-binding protein. We hypothesized that, owing to the critical nature of dsRNA in triggering host innate antiviral responses, E3L-specific small-interfering RNAs [siRNAs] should be effective antiviral agents against pox viruses, for which Vaccinia virus is an appropriate surrogate. In this study, we have utilized two human cell types, namely, HeLa and 293T, one which responds to interferon [IFN]-beta and the other produces and responds to IFN-beta, respectively. The antiviral effects were equally robust in HeLa and 293T cells. However, in the case of 293T cells, several distinct features were observed, when IFN-beta is activated in these cells. Vaccinia virus replication was inhibited by 97% and 98% as compared to control infection in HeLa and 293T cells transfected with E3L-specific siRNAs, respectively. These studies demonstrate the utility of E3L-specific siRNAs as potent antiviral agents for small pox and related pox viruses.

MeSH terms

  • Antiviral Agents / pharmacology*
  • Base Sequence
  • Cell Line
  • Down-Regulation
  • Genes, Viral
  • HeLa Cells
  • Humans
  • Immunity, Innate / drug effects
  • Immunity, Innate / genetics
  • Interferon Type I / pharmacology
  • Interferon-beta / biosynthesis
  • Models, Biological
  • RNA, Small Interfering / genetics*
  • RNA, Small Interfering / pharmacology*
  • RNA-Binding Proteins / antagonists & inhibitors*
  • RNA-Binding Proteins / genetics*
  • Recombinant Proteins
  • Transcription, Genetic
  • Transfection
  • Vaccinia virus / drug effects*
  • Vaccinia virus / genetics*
  • Vaccinia virus / immunology
  • Vaccinia virus / physiology
  • Variola virus / drug effects
  • Variola virus / genetics
  • Variola virus / immunology
  • Viral Proteins / antagonists & inhibitors*
  • Viral Proteins / genetics*
  • Virus Replication / drug effects


  • Antiviral Agents
  • E3L protein, Vaccinia virus
  • Interferon Type I
  • RNA, Small Interfering
  • RNA-Binding Proteins
  • Recombinant Proteins
  • Viral Proteins
  • Interferon-beta