Repair of HCMV-Induced DNA Damage in Infected Cells

人巨细胞病毒（HCMV）是导致出生缺陷的主要病毒，感染所有新生儿的1- 2 每年。大约5-10%的这些先天性感染的婴儿将表现出严重的症状， 出生时的神经系统损伤，可能包括耳聋、失明、智力迟钝和小头畸形。 另有10-15%的人将在头10年内出现感觉神经性听力损失和/或学习障碍 生命我们的长期目标是了解发病率发展背后的机制， 先天性感染HCMV的婴儿死亡率。在过去的几年里，我们研究了 HCMV与允许感染细胞的细胞周期和DNA修复机制的相互作用。我们有 发现HCMV将许多关键的调节和修复蛋白隔离到其病毒复制中心。 然而，它似乎将几个复合物的组分分开，使得所有蛋白质都存在 在复制中心内，但不是所有的都可用于细胞基因组。我们还确定， HCMV可在S期诱导1号染色体特异性损伤。 当结合关于感染后晚期诱导的非特异性损伤的文献时， 数据更清楚地强调了HCMV的遗传毒性作用。我们假设长期有害的 如果1）最初的特异性损伤被传播或2）损伤 在感染后较晚时间发生的损伤由于修复机械的隔离而未被修复。来测试我们 假设，我们提出了三个具体目标。首先，我们将彻底定义染色体的参数 HCMV感染细胞中lq断裂与诱导速度和细胞周期时相有关， 感染我们认为我们的结果必须转移到更临床相关的细胞类型中，特别是 神经系细胞，因为这些细胞在先天性感染期间受病毒影响最严重。 其次，我们还将确定这些临床相关的1号染色体损伤的后果， 细胞，以及是否在半许可的环境中，我们可以观察到1号染色体的繁殖 损伤而不是愈合细胞的破裂或向凋亡的运动。最后，我们将 表征HCMV感染的细胞在接种后晚期修复外源性引入的损伤的能力， 感染，病毒复制中心组装后。

Human Cytomegalovirus (HCMV) is the major viral cause of birth defects, infecting 1-2% of all newborns annually. Approximately 5-10% of these congenitally infected infants will manifest signs of serious neurological damage at birth, which can include deafness, blindness, mental retardation and microcephaly. Another 10-15% will develop sensori-neural hearing loss and/or learning disabilities within the first 10 years of life. Our long-term goat is to understand the mechanism behind the development of morbidity and mortality in infants congenitally infected with HCMV. Over the last several years we have studied the interaction of HCMV with the cell cycle and DNA repair machinery of the permissively infected cell. We have discerned that HCMV sequesters many key regulatory and repair proteins into its viral replication centers. However, it appears to partition the components of several complexes so that all the proteins are present within the replication centers, but not all are available to the cellular genome. We have also determined that HCMV can induce specific damage on chromosome 1 during S-phase. When coupled with the literature regarding nonspecific damage induced at late times post infection our data more clearly highlights the genotoxic effects of HCMV. We hypothesize that long-term detrimental consequences to the cellular genome may occur if 1) the initial specific damage is propagated or 2) damage incurred at late times post infection is not repaired due to sequestration of the repair machinery. To test our hypothesis, we propose three specific aims. First, we will thoroughly define the parameters of chromosome lq breakage in HCMV-infected cells with regard to rapidity of induction and cell cycle phase at time of infection. We think it is imperative that our results be moved into more clinically relevant cell types, especially cells of neural lineage, as these are the cells most severely affected by the virus during congenital infection. Second, we also will determine the consequences of chromosome 1 damage in these clinically relevant cells, and whether in a semi-permissive environment we can observe propagation of the chromosome 1 damage instead of healing of the break or movement of the cell toward apoptosis. Lastly, we will characterize the ability of HCMV-infected cells to repair exogenously introduced damage at late times post infection, after viral replication centers are assembled.