Xu Ke, Zheng Bo-Jian, Zeng Rong, Lu Wei, Lin Yong-Ping, Xue Liang, Li Li, Yang Lei-Lei, Xu Chen, Dai Jie, Wang Fei, Li Qing, Dong Qing-Xi, Yang Rui-Fu, Wu Jia-Rui, Sun Bing
Laboratory of Molecular Virology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai Institutes of Biological Sciences, 225 South Chongqing Road, Shanghai 200025, China.
Virology. 2009 Jun 5;388(2):279-85. doi: 10.1016/j.virol.2009.03.032. Epub 2009 Apr 25.
Eight accessory proteins have been identified in severe acute respiratory syndrome-associated coronavirus (SARS-CoV). They are believed to play roles in the viral life cycle and may contribute to the pathogenesis and virulence. ORF9b as one of these accessory proteins is located in subgenomic mRNA9 and encodes a 98 amino acid protein. However, whether 9b protein is a structural component of SARS-CoV particles remains unknown. In this study, we demonstrate that 9b protein is translated from bicistronic mRNA9 via leaky ribosome scanning and it is incorporated into both virus-like particles (VLPs) and purified SARS-CoV virions. Further analysis shows that sufficient incorporation of 9b protein into VLPs is dependent upon the co-expression of E and M proteins, but not upon the presence of either S or N protein. Our data indicate that 9b protein of SARS-CoV is another virion-associated accessory protein. This finding will lead to a better understanding of the properties of the SARS-CoV 9b protein.
在严重急性呼吸综合征相关冠状病毒（SARS-CoV）中已鉴定出8种辅助蛋白。它们被认为在病毒生命周期中发挥作用，并可能导致发病机制和毒力。作为这些辅助蛋白之一的ORF9b位于亚基因组mRNA9中，编码一种98个氨基酸的蛋白质。然而，9b蛋白是否是SARS-CoV颗粒的结构成分仍不清楚。在本研究中，我们证明9b蛋白通过核糖体渗漏扫描从双顺反子mRNA9翻译而来，并被整合到病毒样颗粒（VLP）和纯化的SARS-CoV病毒粒子中。进一步分析表明，9b蛋白充分整合到VLP中依赖于E蛋白和M蛋白的共表达，而不依赖于S蛋白或N蛋白的存在。我们的数据表明，SARS-CoV的9b蛋白是另一种与病毒粒子相关的辅助蛋白。这一发现将有助于更好地理解SARS-CoV 9b蛋白的特性。
