title: Mutational study of sapovirus expression in insect cells.
abstract: Human sapovirus (SaV), an agent of human gastroenteritis, cannot be grown in cell culture, but expression of the recombinant capsid protein (rVP1) in a baculovirus expression system results in the formation of virus-like particles (VLPs). In this study we compared the time-course expression of two different SaV rVP1 constructs. One construct had the native sequence (Wt construct), whereas the other had two nucleotide point mutations in which one mutation caused an amino acid substitution and one was silent (MEG-1076 construct). While both constructs formed VLPs morphologically similar to native SaV, Northern blot analysis indicated that the MEG-1076 rVP1 mRNA had increased steady-state levels. Furthermore, Western blot analysis and an antigen enzyme-linked immunosorbent assay showed that the MEG-1076 construct had increased expression levels of rVP1 and yields of VLPs. Interestingly, the position of the mutated residue was strictly conserved residue among other human SaV strains, suggesting an important role for rVP1 expression.
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan. ghansman@nih.go.jp
authors.forename: Grant S
authors.initials: GS
authors.lastname: Hansman
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Katayama
authors.forename: Tomoichiro
authors.initials: T
authors.lastname: Oka
authors.forename: Katsuro
authors.initials: K
authors.lastname: Natori
authors.forename: Naokazu
authors.initials: N
authors.lastname: Takeda
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D006801:Humans; D007313:Insecta / Q000166:cytology / Q000821:virology*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins; D029341:Sapovirus / Q000235:genetics* / Q000502:physiology*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D011994:Recombinant Proteins; D014764:Viral Proteins
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