Mechanisms of vaccinia virus dissemination

描述(申请人提供)：痘病毒科的正痘病毒属既包括天花的病原体天花病毒，也包括用于根除天花的疫苗株牛痘病毒。尽管自然发生的天花已被成功根除，但鉴于潜在的生物恐怖袭击和/或流行性传染病(猴痘)的暴发，我们需要更好地了解支持正痘病毒传播的机制。正痘病毒的生命周期依赖于两种感染形式的产生，即细胞内成熟病毒(IMV)和细胞外病毒(EV)。EV是通过将IMV包裹在来自跨高尔基网络的双膜中而形成的。EV外膜与质膜的融合形成细胞相关EV(CEV)。CEV传播的一个中心事件是病毒蛋白A36被Src家族的非受体酪氨酸激酶磷酸化。酪氨酸残基上的A36磷酸化为接头蛋白Nck 1和Grb2创建了对接位点。这些接头介导N-WASP的募集，后者介导肌动蛋白核转录因子Arp2/3的募集和激活。与导致肌动蛋白尾部形成的分子机制不同，介导Src激活的假定受体酪氨酸激酶的同一性尚不清楚。此外，可能与这种假定受体结合的病毒蛋白的身份也是未知的。为了解决这一知识差距，我们结合了我们在支持基于肌动蛋白的运动性、高通量成像和基于RNAi的大规模基因调查机制方面的广泛专业知识。在这个R21的探索性应用中，我们建议(AIM1)确定参与肌动蛋白尾部形成的受体酪氨酸激酶(S)，以及(AIM2)确定参与质膜上受体酪氨酸激酶信号转导的病毒蛋白(S)。这些探索性研究可能提供与治疗和预防由病原体引起的疾病相关的分子和细胞过程的机械性洞察，这些病原体利用肌动蛋白细胞骨架进行传播。

DESCRIPTION (provided by applicant): The Orthopoxvirus genus of the family Poxviridae includes both the causative agent of smallpox, variola virus, and the vaccine strain used for smallpox eradication, Vaccinia virus. Even though naturally occurring smallpox has been successfully eradicated, we need to better understand the mechanisms supporting Orthopoxviruses dissemination in light of potential bioterrorist attacks and/or outbreaks of epizootic infections (monkeypox). The life cycle of Orthopoxviruses relies on the production of two infectious forms, the intracellular mature viruses (IMV) and the extracellular viruses (EV). EV is formed through wrapping of IMV in double membranes derived from the trans-Golgi network. The fusion of the outer membrane of EV to the plasma membrane leads to formation of cellular-associated EV (CEV). A central event in CEV dissemination is phosphorylation of the viral protein A36 by non-receptor tyrosine kinases of the Src family. A36 phosphorylation on tyrosine residues creates docking sites for the adaptor proteins Nck1 and Grb2. These adaptors mediate the recruitment of N- WASP, which mediates the recruitment and activation of the actin nucleator ARP2/3. In contrast to the molecular machinery leading to actin tail formation, the identity of the putative receptor tyrosine kinase mediating Src activation is unknown. Moreover, the identity of the viral protein that may engage this putative receptor is unknown as well. To address this gap in knowledge, we have combined our extensive expertise in the mechanisms supporting actin-based motility, high-throughput imaging and large-scale RNAi-based genetic investigation. In this R21 exploratory application, we propose (Aim1) to determine the receptor tyrosine kinase(s) involved in actin tail formation and (Aim2) to determine the viral protein(s) engaging receptor tyrosine kinase signaling at the plasma membrane. These exploratory studies may provide mechanistic insight into molecular and cellular processes relevant to the treatment and prevention of diseases caused by pathogens that exploit the actin cytoskeleton for their dissemination.