Control of translation by VSV

描述（由申请人提供）：翻译的控制在许多病毒的发病机制中起着至关重要的作用。抑制宿主蛋白合成对抑制宿主抗病毒反应很重要，而病毒mrna的选择性翻译对病毒在宿主内的繁殖很重要。水疱性口炎病毒（VSV）是横纹肌病毒的原型，是非分节负链RNA病毒中研究得最好的例子之一。先前的实验已经清楚地表明，VSV使用新的机制来控制翻译，这与其他已经得到充分研究的RNA病毒（如小核糖核酸病毒和流感病毒）不同。该项目的目的是确定VSV抑制宿主蛋白合成和促进病毒蛋白合成的这些机制。先前的研究表明，由于蛋白激酶r的磷酸化，翻译因子elF2alpha在vsv感染的细胞中失活。然而，我们已经证明，帽结合的elF4F复合物在vsv感染的细胞中也失活。目的1是确定elF4F是如何失活的，以及在vsv感染细胞中，elF4F与elF2alpha失活在抑制宿主蛋白合成方面的相对贡献。目的2是确定负责诱导抑制宿主蛋白质合成的病毒成分。这些研究将使用新的重组病毒来绘制VSV突变体的基因图谱，这些突变体在抑制宿主翻译方面比野生型VSV更有效或更不有效。目的3是确定病毒mrna对翻译抑制的抗性基础。这些实验将使用含有病毒或宿主5‘和3’非翻译区的嵌合mrna来测试是否存在增强病毒mrna翻译的顺式作用序列。我们还将测试表达这些嵌合mRNA的重组病毒，以确定由病毒转录酶合成的mRNA是否能抵抗翻译抑制。在完成这些实验后，我们将获得关于病毒如何抑制宿主抗病毒反应以及它们如何促进自身基因产物表达的重要新信息。这些实验的结果将是新颖的，因为VSV使用的机制与其他得到充分研究的原型病毒有很大不同。最后，很可能存在宿主mrna使用与VSV mrna类似的机制来增强其在应激等条件下的翻译。因此，我们期望在翻译起始因子活性受到抑制的其他条件下对细胞翻译的调节获得新的见解。

DESCRIPTION (provided by applicant): The control of translation plays a critical role in the pathogenesis of many viruses. The inhibition of host protein synthesis is important for suppression of the host antiviral response, while the selective translation of viral mRNAs is important for virus propagation in the host. Translational control by vesicular stomatitis virus (VSV), the prototype rhabdovirus, is one of the best studied examples among the nonsegmented negative stranded RNA viruses. Previous experiments have made it clear that VSV uses novel mechanisms to control translation that are distinct from those of other well-studied RNA viruses, such as picornaviruses and influenza viruses. The goal of this project is to determine these mechanisms by which VSV inhibits host protein synthesis and promotes viral protein synthesis. Previous work has shown that the translation factor elF2alpha is inactivated in VSV-infected cells as a result of phosphorylation by protein kinase R. However, we have shown that the cap-binding elF4F complex is also inactivated in VSV-infected cells. Aim 1 is to determine how elF4F is inactivated, and the relative contribution of elF4F versus elF2alpha inactivation in the inhibition of host protein synthesis in VSV-infected cells. Aim 2 is to determine the viral components responsible for inducing the inhibition of host protein synthesis. These studies will use new recombinant viruses to map the genes of VSV mutants that are either more effective or less effective than wild-type VSV in the inhibition of host translation. Aim 3 is to determine the basis of resistance of viral mRNAs to the inhibition of translation. These experiments will use chimeric mRNAs containing viral or host 5' and 3' untranslated regions to test for the presence of cis-acting sequences that enhance translation of viral mRNAs. We will also test recombinant viruses that express these chimeric mRNAs to determine whether mRNA synthesis by the viral transcriptase confers the resistance to the inhibition of translation. Upon completion of these experiments we will have important new information about how viruses suppress the antiviral response in the host, and how they promote expression of their own gene products. The results of these experiments will be novel, because the mechanisms used by VSV differ substantially from those of other well-studied prototype viruses. Finally, it is very likely that there are host mRNAs that use mechanisms similar to those of VSV mRNAs to enhance their translation under conditions such as stress. Thus we expect to gain new insight into regulation of cellular translation under other conditions where the activities of translation initiation factors are inhibited.