Conserved Eukaryotic Fusogens Can Fuse Viral Envelopes to Cells

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Science  24 Mar 2011:
DOI: 10.1126/science.1202333


Caenorhabditis elegans AFF-1 and EFF-1 (CeFFs) proteins are essential for developmental cell-to-cell fusion and can merge insect cells. To study the structure and function of AFF-1, we constructed vesicular stomatitis virus (VSV) displaying AFF-1 on the viral envelope, substituting the native fusogen VSVG. Electron microscopy and tomography revealed that AFF-1 formed distinct supercomplexes resembling pentameric and hexameric flowers on pseudoviruses. Viruses carrying AFF-1 infected mammalian cells only when CeFFs were on the target cell surface. Furthermore, we identified fusion family proteins (FFs) within and beyond nematodes and divergent members from the human parasitic nematode Trichinella spiralis and the chordate Branchiostoma floridae could also fuse mammalian cells. Thus, FFs comprise an ancient family of cellular fusogens that can promote fusion when expressed on a viral particle.

  • * Present address: Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.