Novel Translational Control Mechanisms in Host Range Restriction of Poxvirus

所有的病毒都依赖宿主的翻译机制来合成蛋白质。因此，翻译 控制构成了对病毒的通用宿主防御。关于如何主持的新认识 调节翻译对病毒感染的反应以及病毒如何逃避这种宿主反应 为病毒发病机制提供基本见解，有利于新型抗病毒药物的开发 战略。 痘病毒包括一些危险的新兴病原体以及一些有希望的疫苗。 向量。与许多其他病毒不同，痘病毒的宿主范围不受进入步骤的影响，但 受细胞内过程的限制。特别是，细胞翻译控制通路有一个 对痘病毒宿主范围的深刻影响，以及这些途径的痘病毒抑制剂可能 表现为关键的宿主范围因素。最著名的例子是PKR介导的控制 两种痘苗病毒(VACV)宿主范围蛋白E3的翻译启动及其拮抗作用 和K3。对于两个关键的靶向的PKR非依赖性通路的了解要少得多 VACV宿主范围蛋白K1和C7。在K1和C7中都有缺失的VACV无法复制 在大多数哺乳动物细胞中，由于病毒和宿主蛋白质合成的中断。有趣的是， 翻译关闭独立于PKR和RNASL，似乎不涉及任何 翻译启动因素。一对类似的干扰素刺激基因SAMD9和 SAMD9L(SAMD9和L)最近被我们和其他人确定为K1的特异性靶标 和C7。然而，它们调节蛋白质合成和限制痘病毒宿主范围的方式是 未知，也是这项提案的重点。 我们为理解K1/C7及其细胞学做出了持续的贡献 十多年来的目标，包括确定K1/C7和 SAMD9L作为K1/C7细胞靶点的鉴定此外，我们已经获得了令人信服的 导致我们的新假设的初步数据，这些假设将与 遵循特定的目标。 目的1.确定SAMD9是如何被激活以抑制蛋白质合成的。 目的2.确定活化的SAMD9如何抑制蛋白质合成。 目的3.确定寄主种特异性SAMD9和L的分子基础 OPXV抑制剂的抑制作用。

All viruses rely on host translational machinery for protein synthesis. As such, translation control constitutes a universal host defense against viruses. A new understanding on how host regulates translation in response to viral infection and how viruses evade this host response will provide fundamental insight into viral pathogenesis and benefit the development of new antiviral strategies. Poxviruses include some dangerous emerging pathogens as well as some promising vaccine vectors. Unlike many other viruses, poxvirus host range is not affected by the entry step but restricted by intracellular processes. Particularly, cellular translational control pathways have a profound impact on poxvirus host range, and poxvirus inhibitors of these pathways could manifest as critical host-range factors. The best-known example is PKR-mediated control of translation initiation and its antagonism by two vaccinia virus (VACV) host-range proteins E3 and K3. Much less is understood about a PKR-independent pathway targeted by two critical VACV host-range proteins, K1 and C7. VACV with deletion in both K1 and C7 fails to replicate in most mammalian cells due to a shut-off of viral and host protein synthesis. Intriguingly, the translational shut-off is independent of PKR and RNaseL and appears not to involve any translation initiation factors. A paralogous pair of interferon-stimulated genes, SAMD9 and SAMD9L (SAMD9&L), were recently identified by us and others as the specific targets of K1 and C7. However, how they regulate protein synthesis and restrict poxvirus host range is unknown and is the focus of this proposal. We have made sustained contributions to the understanding of K1/C7 and their cellular targets for over a decade, including the determination of the structures of K1/C7 and the identification of SAMD9L as a cellular target of K1/C7. In addition, we have obtained compelling preliminary data that led to our novel hypotheses, which will be addressed separately with the following specific aims. Aim 1. To determine how SAMD9 is activated to inhibit protein synthesis. Aim 2. To determine how activated SAMD9 inhibits protein synthesis. Aim 3. To determine the molecular basis underlying the host species-specific SAMD9&L inhibition by OPXV inhibitors.