title: Replication-competent influenza A virus that encodes a split-green fluorescent protein-tagged PB2 polymerase subunit allows live-cell imaging of the virus life cycle.
abstract: Studies on the intracellular trafficking of influenza virus ribonucleoproteins are currently limited by the lack of a method enabling their visualization during infection in single cells. This is largely due to the difficulty of encoding fluorescent fusion proteins within the viral genome. To circumvent this limitation, we used the split-green fluorescent protein (split-GFP) system (S. Cabantous, T. C. Terwilliger, and G. S. Waldo, Nat. Biotechnol. 23:102-107, 2005) to produce a quasi-wild-type recombinant A/WSN/33/influenza virus which allows expression of individually fluorescent PB2 polymerase subunits in infected cells. The viral PB2 proteins were fused to the 16 C-terminal amino acids of the GFP, whereas the large transcomplementing GFP fragment was supplied by transient or stable expression in cultured cells that were permissive to infection. This system was used to characterize the intranuclear dynamics of PB2 by fluorescence correlation spectroscopy and to visualize the trafficking of viral ribonucleoproteins (vRNPs) by dynamic light microscopy in live infected cells. Following nuclear export, vRNPs showed a transient pericentriolar accumulation and intermittent rapid (∼1 μm/s), directional movements in the cytoplasm, dependent on both microtubules and actin filaments. Our data establish the potential of split-GFP-based recombinant viruses for the tracking of viral proteins during a quasi-wild-type infection. This new virus, or adaptations of it, will be of use in elucidating many aspects of influenza virus host cell interactions as well as in screening for new antiviral compounds. Furthermore, the existence of cell lines stably expressing the complementing GFP fragment will facilitate applications to many other viral and nonviral systems.
authors: European Molecular Biology Laboratory, Grenoble Outstation, Grenoble, France.
authors: Sergiy V
authors: SV
authors: Avilov
authors: Dorothée
authors: D
authors: Moisy
authors: Sandie
authors: S
authors: Munier
authors: Oliver
authors: O
authors: Schraidt
authors: Nadia
authors: N
authors: Naffakh
authors: Stephen
authors: S
authors: Cusack
mesh_terms: D002460:Cell Line; D019084:Fluorescent Antibody Technique, Indirect; D049452:Green Fluorescent Proteins / Q000235:genetics*; D006801:Humans; D009980:Influenza A virus / Q000235:genetics / Q000502:physiology*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics*; D014779:Virus Replication
chemical_list: C057027:PB2 protein, Influenzavirus A; D014764:Viral Proteins; D049452:Green Fluorescent Proteins; D012324:RNA-Dependent RNA Polymerase