Homo-oligomerization Facilitates the Interferon-Antagonist Activity of the Ebolavirus VP35 Protein

Virology. 2005 Oct 25;341(2):179-89. doi: 10.1016/j.virol.2005.06.044. Epub 2005 Aug 10.

Abstract

We have identified a putative coiled-coil motif within the amino-terminal half of the ebolavirus VP35 protein. Cross-linking studies demonstrated the ability of VP35 to form trimers, consistent with the presence of a functional coiled-coil motif. VP35 mutants lacking the coiled-coil motif or possessing a mutation designed to disrupt coiled-coil function were defective in oligomerization, as deduced by co-immunoprecipitation studies. VP35 inhibits signaling that activates interferon regulatory factor 3 (IRF-3) and inhibits (IFN)-alpha/beta production. Experiments comparing the ability of VP35 mutants to block IFN responses demonstrated that the VP35 amino-terminus, which retains the putative coiled-coil motif, was unable to inhibit IFN responses, whereas the VP35 carboxy-terminus weakly inhibited the activation of IFN responses. IFN-antagonist function was restored when a heterologous trimerization motif was fused to the carboxy-terminal half of VP35, suggesting that an oligomerization function at the amino-terminus facilitates an "IFN-antagonist" function exerted by the carboxy-terminal half of VP35.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Motifs
  • Blotting, Western
  • Cell Line
  • Chloramphenicol O-Acetyltransferase / analysis
  • Chloramphenicol O-Acetyltransferase / genetics
  • Ebolavirus / chemistry*
  • Ebolavirus / genetics
  • Genes, Reporter
  • Humans
  • Immunoprecipitation
  • Interferons / antagonists & inhibitors*
  • Interferons / genetics
  • Luciferases / analysis
  • Luciferases / genetics
  • Mutation, Missense
  • Nucleoproteins / chemistry
  • Nucleoproteins / genetics
  • Nucleoproteins / metabolism
  • Nucleoproteins / physiology*
  • Protein Structure, Tertiary
  • Sequence Deletion
  • Viral Core Proteins / chemistry
  • Viral Core Proteins / genetics
  • Viral Core Proteins / metabolism
  • Viral Core Proteins / physiology*

Substances

  • Nucleoproteins
  • Viral Core Proteins
  • nucleoprotein VP35, Ebola virus
  • Interferons
  • Luciferases
  • Chloramphenicol O-Acetyltransferase