Chromosome 1 Damage in HCMV Infected Cells

描述(申请人提供)：人巨细胞病毒(HCMV)是主要的 病毒导致出生缺陷，每年感染1%-2%的新生儿。 大约5%-10%的先天感染婴儿将出现 出生时有严重神经损伤的迹象，包括耳聋， 失明、智力低下和小头畸形。另有10%-15%的人会 发展感觉神经性听力损失和/或学习障碍 生命的头10年。我们的长期目标是了解这一机制 婴儿先天发病率和死亡率发展的背后 感染了人巨细胞病毒。为此，我们研究了人巨细胞病毒与病毒的相互作用 允许感染细胞的细胞周期和DNA修复机制 在过去几年里。我们已经了解到的是，HCMV隔离了许多 维护和维修的主要参与者进入其病毒复制中心。 然而，它似乎分割了几个复合体的成分，以便 所有的蛋白质都存在于复制中心，但并不是所有的都存在 可用于细胞基因组。我们还确定了人巨细胞病毒可以诱导 当细胞在1q21和1q42位置时，非常特异的遗传毒性损伤 感染时间为S期。 再加上其他人关于晚些时候造成的非特定损害的报告 在感染之后，越来越明显的是，人巨细胞病毒确实具有遗传毒性 寄主细胞基因组。我们假设长期的有害后果 对细胞基因组的损伤可能发生在1)这种最初的特异性损伤是 传播的或2)在感染后晚期造成的损害没有修复 由于维修机械的封存。为了检验我们的假设，我们 提出三个具体目标。首先，我们将彻底定义 人巨细胞病毒感染细胞染色体1q断裂与染色体断裂速度的关系 感染时的诱导和细胞周期时相。我们还将确定 破解诱导需要哪些病毒粒子成分。我们认为它是 当务之急是将我们的结果转移到更多临床相关的细胞类型中， 尤其是神经系的细胞，因为这些细胞是最严重的 在先天性感染期间受到病毒的影响。第二，我们还将 确定1号染色体损伤在这些临床相关疾病中的后果 细胞，以及我们是否能在半允许的环境中观察到传播 而不是修复1号染色体的断裂或运动 细胞走向凋亡。最后，我们将描述 人巨细胞病毒感染细胞修复外源性损伤后的后期 感染，在病毒复制中心组装后。我们相信 我们在培养中获得的结果将有助于我们理解中央 观察到先天性感染婴儿的神经系统问题。

DESCRIPTION (provided by applicant): Human Cytomegalovirus (HCMV) is the major viral cause of birth defects, infecting 1-2 percent of all newborns annually. Approximately 5-10 percent 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 percent will develop sensori-neural hearing loss and/or learning disabilities within the first 10 years of life. Our long-term goal is to understand the mechanism behind the development of morbidity and mortality in infants congenitally infected with HCMV. To this end, we have studied the interaction of HCMV with the cell cycle and DNA repair machinery of the permissively infected cell over the last several years. What we have discerned is that HCMV sequesters many of the key players of maintenance and repair 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 very specific genotoxic damage at positions 1q21 and 1q42 when cells are infected during S-phase. Coupled with reports of others regarding the nonspecific damage induced at late times post infection, it is becoming more clear that HCMV is indeed genotoxic to the host cell genome. We hypothesize that long-term detrimental consequences to the cellular genome may occur if 1) this 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 1q breakage in HCMV-infected cells with regard to rapidity of induction and cell cycle phase at time of infection. We will also determine what virion components are required for break induction. 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. It is our belief that results we obtain in culture will aid in our understanding of the central nervous system problems observed in congenitally infected infants.