The polypyrimidine tract binding protein is required for efficient picornavirus gene expression and propagation
The polypyrimidine tract binding protein is required for efficient picornavirus gene expression and propagation
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DOI：
10.1128/jvi.79.10.6172-6179.2005
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发表时间：
2005-05-01
影响因子：
5.4
通讯作者：
Garcia-Blanco, MA
中科院分区：
文献类型：
--
作者：
Florez, PM;Sessions, OM;Garcia-Blanco, MA
病毒基因高效表达和繁殖所需的哺乳动物宿主因子经常被遗传分析所忽视。一个恰当的例子是反式激活内部核糖体进入位点（IRES）驱动的翻译的细胞因子的功能，这在许多正链RNA病毒中起作用，包括所有的小核糖核酸病毒。这些IRES反式作用因子已经在体外进行了很好的研究，但它们在体内对病毒基因表达和繁殖的重要性还没有得到广泛的实验证实。在这里，我们使用RNA干扰，以消除哺乳动物细胞的一个这样的因素，聚嘧啶道结合蛋白，并测试其在小RNA病毒基因表达和繁殖的要求。耗尽的聚嘧啶道结合蛋白导致颗粒传播的显着延迟，并显着降低脊髓灰质炎病毒和脑心肌炎病毒的病毒蛋白的合成和积累。这些影响可以部分恢复的RNA干扰抗性外源性多聚嘧啶道结合蛋白的表达。这些数据表明，在小核糖核酸病毒基因表达的多聚嘧啶道结合蛋白的关键作用，并强烈建议有效的IRES依赖的翻译的要求。
Mammalian host factors required for efficient viral gene expression and propagation have been often recalcitrant to genetic analysis. A case in point is the function of cellular factors that trans-activate internal ribosomal entry site (IRES)-driven translation, which is operative in many positive-stranded RNA viruses, including all picomaviruses. These IRES trans-acting factors have been elegantly studied in vitro, but their in vivo importance for viral gene expression and propagation has not been widely confirmed experimentally. Here we use RNA interference to deplete mammalian cells of one such factor, the polypyrimidine tract binding protein, and test its requirement in picornavirus gene expression and propagation. Depletion of the polypyrimidine tract binding protein resulted in a marked delay of particle propagation and significantly decreased synthesis and accumulation of viral proteins of poliovirus and encephalomyocarditis virus. These effects could be partially restored by expression of an RNA interference-resistant exogenous polypyrimidine tract binding protein. These data indicate a critical role for the polypyrimidine tract binding protein in picornavirus gene expression and strongly suggest a requirement for efficient IRES-dependent translation.