title: Conformational maturation of the nucleoprotein synthesized in influenza C virus-infected cells.
abstract: The conformational maturation of the influenza C virus nucleoprotein (NP) synthesized in infected cells was investigated. Monoclonal antibodies (mAbs) that have previously been characterized [Sugawara, K., Nishimura, H., Hongo, S., Kitame, F., Nakamura, K., 1991. Antigenic characterization of the nucleoprotein and matrix protein of influenza C virus with monoclonal antibodies. J. Gen. Virol. 72, 103-109] enabled this molecular maturation to be detected. Both pulse-labeled and chased NPs could equally retain high reactivity with H31 mAb recognizing a linear epitope on the NP molecule. However, pulse-labeled NP showed three- to four-fold lower reactivity with H27 mAb recognizing a conformational epitope, compared to chased NP. Sedimentation analyses by sucrose gradient centrifugation revealed that the mature NP could readily participate in nucleocapsid formation while the immature NP was free. The immature NP was rapidly transported into the nucleus and its maturation seemed to occur after or during translocation into the nucleus. A single expression of NP cDNA in COS-1 cells demonstrated that the NP maturation was an intrinsic feature of the NP molecule without relation to other viral components.
authors.affiliation: Department of Infectious Diseases, Yamagata University School of Medicine, Iida-Nishi, Yamagata 990-9585, Japan. ksugawar@med.idiyamagata-u.ac.jp
authors.forename: Kanetsu
authors.initials: K
authors.lastname: Sugawara
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Muraki
authors.forename: Emi
authors.initials: E
authors.lastname: Takashita
authors.forename: Yoko
authors.initials: Y
authors.lastname: Matsuzaki
authors.forename: Seiji
authors.initials: S
authors.lastname: Hongo
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D002499:Centrifugation, Density Gradient; D002522:Chlorocebus aethiops; D004285:Dogs; D000939:Epitopes / Q000276:immunology; D009982:Gammainfluenzavirus / Q000502:physiology*; D019251:Nucleocapsid / Q000096:biosynthesis; D009698:Nucleoproteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D014764:Viral Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000939:Epitopes; D009698:Nucleoproteins; D014764:Viral Proteins