Hansman Grant S, Katayama Kazuhiko, Oka Tomoichiro, Natori Katsuro, Takeda Naokazu
Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
Virol J. 2005 Feb 23;2:13. doi: 10.1186/1743-422X-2-13.
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.
人札幌病毒（SaV）是引起人类肠胃炎的病原体，无法在细胞培养中生长，但在杆状病毒表达系统中重组衣壳蛋白（rVP1）的表达会导致病毒样颗粒（VLP）的形成。在本研究中，我们比较了两种不同的SaV rVP1构建体的时间进程表达。一种构建体具有天然序列（野生型构建体），而另一种具有两个核苷酸点突变，其中一个突变导致氨基酸替换，另一个是沉默突变（MEG-1076构建体）。虽然两种构建体形成的VLP在形态上与天然SaV相似，但Northern印迹分析表明MEG-1076 rVP1 mRNA的稳态水平有所增加。此外，蛋白质印迹分析和抗原酶联免疫吸附测定表明，MEG-1076构建体的rVP1表达水平和VLP产量有所增加。有趣的是，突变残基的位置在其他人类SaV毒株中是严格保守的残基，这表明rVP1表达具有重要作用。
