Homo-oligomerization facilitates the interferon-antagonist activity of the ebolavirus VP35 protein.
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.
Reid
St Patrick
SP
Department of Microbiology, Box 1124, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, USA.
Cárdenas
Washington B
WB
Basler
Christopher F
CF
D020816:Amino Acid Motifs; D015153:Blotting, Western; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis / Q000235:genetics; D029043:Ebolavirus / Q000737:chemistry* / Q000235:genetics; D017930:Genes, Reporter; D006801:Humans; D047468:Immunoprecipitation; D007372:Interferons / Q000037:antagonists & inhibitors* / Q000235:genetics; D008156:Luciferases / Q000032:analysis / Q000235:genetics; D020125:Mutation, Missense; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion; D014758:Viral Core Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D014758:Viral Core Proteins; C084818:nucleoprotein VP35, Ebola virus; D007372:Interferons; D008156:Luciferases; D015500:Chloramphenicol O-Acetyltransferase