Comprehensive genetic dissection of poxvirus membrane assembly and function

感染哺乳动物的痘病毒的正痘病毒属（正痘病毒）成员的人畜共患潜力代表了对全球公共卫生的持续威胁。正痘病毒在宿主细胞质中增殖的复杂生物学的标志是产生两种不同的感染形式-细胞内成熟病毒体（IMV），其保持主要与细胞相关，和包膜病毒体（EV），其对于细胞外病毒传播至关重要。EV在其表面具有八种病毒编码的膜蛋白的独特互补，其影响组织嗜性、长距离体内传播并最终影响毒力;为疫苗诱导的和治疗性抗体提供关键靶点;并且是溶瘤痘病毒载体的治疗潜力的重要决定因素。尽管它们的重要性，全面了解电动汽车的挑战是由病毒-宿主和病毒-病毒相互作用的复杂网络，其基础的形态和功能。我们的总体目标是通过遗传学和蛋白质组学方法的结合来解开这些功能蛋白质相互作用网络。使用原型正痘病毒，牛痘病毒（VACV）中任何基因组位点的无偏和深度诱变的新平台，我们在感染性病毒颗粒的背景下对两种EV蛋白A33和A34进行了深度突变扫描（DMS），并确定了增强EV适应性的新型区域特异性突变。我们将阐明这些突变体的作用机制。同时，我们将进行遗传修饰和蛋白质组学筛选，以发现A33/A34与病毒和宿主蛋白质的新功能相互作用。总的来说，这些研究将提供关于EV如何在感染过程中组装、外出和传播到新细胞的新信息，EV对正痘病毒的毒力及其作为溶瘤载体的效用至关重要。

The zoonotic potential of members of the genus Orthopoxvirus (orthopoxviruses) of mammal- infecting poxviruses represent a continued threat to global public health. A hallmark of the complex biology of orthopoxvirus multiplication in the host cell cytoplasm is the generation of two distinct infectious forms—intracellular mature virions (IMV), which remain largely cell- associated, and enveloped virions (EV), which are critical for extracellular viral spread. EVs bear a unique complement of eight virus-encoded membrane proteins at their surface that influence tissue tropism, long-range in vivo dissemination, and ultimately, virulence; provide key targets for vaccine-induced and therapeutic antibodies; and are important determinants of the therapeutic potential of oncolytic poxvirus vectors. Despite their importance, a comprehensive understanding of EVs is challenged by the complex networks of virus-host and virus-virus interactions that underlie their morphogenesis and function. Our overall objective is to unravel these functional protein interaction networks through a combination of genetic and proteomic approaches. Using a new platform for unbiased and deep mutagenesis of any genomic locus in the prototypic orthopoxvirus, vaccinia virus (VACV), we conducted deep-mutational scans (DMS) of two EV proteins, A33 and A34, in the context of infectious viral particles and identified novel regiospecific mutations that enhance EV fitness. We will elucidate the mechanisms of action of these mutants. In parallel, we will perform genetic modifier and proteomic screens to uncover new functional interactions of A33/A34 with viral and host proteins. Collectively, these studies will provide new information on how EVs—critical for both the virulence of orthopoxviruses and their utility as oncolytic vectors—assemble, egress, and spread to new cells during infection.