Evolutionary potential of a model poxvirus

描述（由申请人提供）：病原体产生各种各样的因子，这些因子与宿主成分相互作用以促进感染。许多这类因子类似或模仿宿主蛋白。参与这些宿主-病原体相互作用的蛋白质是基因组中进化最快的一些因素。然而，人们对这种快速进化对宿主-病原体关系的影响知之甚少。本研究项目旨在研究宿主和病原体相互作用蛋白的快速进化，重点研究痘苗模型痘病毒。Aim 1将在项目的K99阶段完成，研究一种称为K3L的快速进化痘病毒蛋白的起源和进化，K3L模仿抗病毒蛋白激酶R （PKR）的底物来破坏抗病毒活性。进化分析将指导祖先K3L变异的重建，而细胞分析和实验病毒感染将测试这些重建进化步骤的效力。目的2研究K3L从天花的进化，一种毁灭性的人类病原体。重点关注啮齿类动物对PKR的K3L敏感性的实验将验证天花起源于特定啮齿动物宿主的假设。该计划的目标3涉及牛痘病毒在不同宿主细胞系中的实验进化。牛痘将在受控条件下在细胞系中反复传代，并监测基因组变化和潜在的适应性。这一目标和目标2将在项目的K99阶段启动，并将提供宿主和病原体相互作用因素之间进化适应的广泛数据。从这些实验中产生的数据将成为Aim 3中提出的持续项目的基础，这些项目将在项目的独立阶段进行。本课程的所有实验目标都将培养建立独立研究实验室的重要技能。对宿主和病原体相互作用因素之间进化动力学的研究将为痘病毒的进化策略提供新的见解，痘病毒是一类潜在的危险病原体，有望成为自然流行病和/或用作生物恐怖主义的媒介。

DESCRIPTION (provided by applicant): Pathogens produce an enormous variety of factors that interact with host components to promote infections. Many such factors resemble or mimic host proteins. Proteins involved in these host-pathogen interactions are some of the most rapidly evolving factors in genomes. Yet little is known about the consequences of this rapid evolution on host-pathogen relationships. This research program aims to examine rapid evolution of interacting host and pathogen proteins by focusing on the model poxvirus, vaccinia. Aim 1, which will be completed in the K99 phase of the project, investigates the origins and evolution of a fast evolving poxvirus protein called K3L that mimics the substrate of the anti-viral Protein kinase R (PKR) to disrupt anti-viral activity. Evolutionary analysis will guide the reconstruction of ancestral K3L variants, while cellular assays and experimental viral infections will test the potency of these reconstructed evolutionary steps. Aim 2 investigates the evolution of K3L from smallpox, a devastating human pathogen. Experiments focusing on K3L sensitivity to PKR from rodents will test the hypothesis that smallpox emerged from a specific rodent host. Aim 3 of this program entails experimental evolution of vaccinia virus in different host cell lines. Vaccinia will be repeatedly passaged in cell lines under controlled conditions and monitored for genomic changes and potential adaptations. This aim, along with Aim 2, will be initiated during the K99 phase of the project, and will provide extensive data on evolutionary adaptations between interacting host and pathogen factors. The data generated from these experiments will be the foundation of continuing projects proposed in Aim 3 that will be conducted during the independent phase of the project. All the experimental aims of this program will develop important skills for establishing an independent research laboratory. This investigation of the evolutionary dynamics between interacting host and pathogen factors will provide new insights into the evolutionary strategies of poxviruses, a potentially dangerous class of pathogens poised for natural epidemics and/or use as agents of bio-terrorism. Public Health Relevance: Poxviruses are large DNA viruses that infect animals and humans. Smallpox is a Center for Disease Control high-threat (Category A) agent and monkeypox may be poised for epidemic infections of human populations. This project takes an evolutionary approach to understanding how poxviruses adapt to exploit their hosts, so that these evolutionary strategies might be counteracted for the protection of human health.