Evolution and mechanisms of cytomegalovirus antagonism of host cell defenses

巨细胞病毒拮抗宿主细胞防御的进化和机制

基本信息

批准号：
10376227
负责人：
ADAM P. GEBALLE
金额：
$ 44.01万
依托单位：
FRED HUTCHINSON CANCER CENTER
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10376227
关键词：
African Green Monkey Alleles Amino Acids Binding Cebidae Cells Cercopithecidae Clinical Codon Nucleotides Complement Conflict (Psychology)Consequentialism Cyclic AMP-Dependent Protein Kinases Cytomegalovirus Cytomegalovirus Infections DNA DNA Viruses Defect Disease Dissection Endothelium Epithelial Event Evolution Experimental Models Fibroblasts Gene Amplification Gene Duplication Gene Family Genes Genetic Genetic Recombination Genome Genomics Goals High-Throughput DNA Sequencing Horizontal Gene Transfer Host Defense Hot Spot Human IRS1 gene Immunocompromised Host Infection Integration Host Factors Interferons Life Measures Mediating Medical Modeling Molecular Mutate Mutation Neurofibromin 2 Neurologic Neurologic Deficit Pathogenesis Pathway interactions Patients Phenotype Phosphotransferases Physiological Play Predisposition Process Protein Biosynthesis Protein Region Proteins RNA Research Rhesus Role Saimiri Serial Passage Side Signal Transduction Site Structure System Techniques Testing Transgenes Transgenic Organisms Variant Viral Viral Genome Viral Proteins Virus Virus Diseases Virus Replication antagonist arms race cell type disability experimental study immune system function improved infant infection inflammatory milieu inhibitor insight monocyte mutant mutation screening neonatal infection nonhuman primate overexpression preference pressure prevent protein kinase R response viral fitness

项目摘要

Project Summary/Abstract Human cytomegalovirus (HCMV) causes life-threatening diseases in patients with poor immune system function and long-lasting neurological disabilities in congenitally-infected newborns. In addition to its medical importance, HCMV and related viruses provide a powerful experimental model for investigating how viruses evolve to elude host cell defense systems. The long-term goal of this research is to discover evolutionary and molecular mechanisms by which viruses like HCMV control the host cell's protein synthesis machinery to allow viral replication. One of the defense systems that inhibits many viruses is mediated by protein kinase R (PKR). HCMV encodes two protein antagonists of PKR, TRS1 and IRS1, at least one of which is absolutely essential for the virus to replicate in human cells. Aim 1 seeks to understand why HCMV, like several other large DNA viruses, has two genes that serve the same function. Studies of mutant viruses that have only one of the genes will be used to determine why viruses lacking TRS1 have a replication defect not observed with viruses lacking just IRS1. Other experiments will reveal whether the combination of both genes confers a benefit to the virus under conditions that more closely model natural infections than previous studies, such as when clinical strains of HCMV infect different types of cells, and when they encounter an inflammatory environment. Aim 2 will elucidate mechanisms by which CMV can adapt to overcome PKR using gene duplication and horizontal gene transfer, two processes that have had major impacts on the evolution of large DNA viruses. Aim 3 will dissect how a domain in PKR that is critical for its activity has adapted to maintain its function in defending the host, while changing enough to evade viral factors. Comparisons of variants of this domain in humans, Old World monkeys, and New World monkeys, using the powerful technique of “deep mutational scanning” in which each amino acid in a protein is mutated to all of the other 19 alternatives, will reveal how this region of PKR has evolved and how in turn CMVs have evolved to adapt to the changes. These studies will reveal insights into the mechanisms and evolution of both viral and host factors that are in conflict and that determine whether the virus replicates or is successfully blocked by host defenses.

项目概要/摘要人类巨细胞病毒 (HCMV) 会导致免疫系统较差的患者罹患危及生命的疾病除了医学之外，先天性感染新生儿的功能和长期神经系统疾病。重要的是，HCMV 和相关病毒为研究病毒如何进化以逃避宿主细胞防御系统这项研究的长期目标是发现进化和 HCMV 等病毒控制宿主细胞蛋白质合成机制的分子机制抑制许多病毒的防御系统之一是由蛋白激酶 R (PKR) 介导的。 HCMV编码PKR的两种蛋白拮抗剂，TRS1和IRS1，至少其中一种是绝对必需的目标 1 旨在了解 HCMV 与其他几种大 DNA 一样如何在人类细胞中复制。病毒，有两个具有相同功能的基因研究仅具有其中一个基因的突变病毒。将用于确定为什么缺乏 TRS1 的病毒具有复制缺陷，而缺乏 TRS1 的病毒则没有观察到这种缺陷。只是 IRS1，其他实验将揭示这两个基因的组合是否会给病毒带来好处。在比以前的研究更接近地模拟自然感染的条件下，例如当临床菌株时 HCMV 会感染不同类型的细胞，当它们遇到炎症环境时，Aim 2 就会出现这种情况。阐明 CMV 通过基因复制和水平复制克服 PKR 的机制基因转移，这两个过程对大型 DNA 病毒的进化产生了重大影响。剖析 PKR 中对其活动至关重要的域如何适应以维持其功能保护宿主，同时进行足够的改变以逃避病毒因素。在人类、旧世界猴子和新世界猴子中，使用“深度突变”的强大技术扫描”，其中蛋白质中的每个氨基酸都突变为所有其他 19 种替代品，将揭示这种情况是如何发生的 PKR 区域已经进化，CMV 又如何进化以适应这些变化。揭示对冲突的病毒和宿主因素的机制和进化的见解确定病毒是否复制或是否被宿主防御成功阻止。