title: Nuclear trafficking of influenza virus ribonuleoproteins in heterokaryons.
abstract: The influenza virus nucleoprotein (NP), matrix protein (M1), and ribonucleoproteins (vRNPs) undergo regulated nuclear import and export during infection. Their trafficking was analyzed by using interspecies heterokaryons containing nuclei from infected and uninfected cells. Under normal conditions, it was demonstrated that the vRNPs which were assembled in the nucleus and transported to the cytosol were prevented from reimport into the nucleus. To be import competent, they must first assemble into virions and enter by the endosomal entry pathway. In influenza virus mutant ts51, in which M1 is defective, direct reimport took place but was inhibited by heterologous expression of wild-type M1. These data confirm M1's role as the inhibitor of premature nuclear import and as the main regulator of nuclear transport of vRNPs. In addition to this vRNP shuttling, M1 also shuttled between the nucleus and the cytoplasm in ts51-infected cells. When NP was expressed in the absence of virus infection, it was also found to be a shuttling protein.
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA.
authors.forename: G
authors.initials: G
authors.lastname: Whittaker
authors.forename: M
authors.initials: M
authors.lastname: Bui
authors.forename: A
authors.initials: A
authors.lastname: Helenius
mesh_terms: D000818:Animals; D002417:Cattle; D002459:Cell Fusion; D002460:Cell Line; D002467:Cell Nucleus / Q000502:physiology* / Q000648:ultrastructure / Q000821:virology; D003600:Cytosol / Q000502:physiology; D004285:Dogs; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D009980:Influenza A virus / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D018613:Microscopy, Confocal; D012261:Ribonucleoproteins / Q000378:metabolism*; D014763:Viral Matrix Proteins / Q000378:metabolism*; D014771:Virion / Q000502:physiology*; D014779:Virus Replication
chemical_list: D012261:Ribonucleoproteins; D014763:Viral Matrix Proteins