Role of DNA damage in the early steps of HSV infection and latency in neurons

描述（由申请人提供）：1型单纯疱疹病毒（HSV-1）是一种人类DNA病毒，可引起许多涉及人类神经系统的疾病，包括角膜炎和脑炎。该病毒的特征在于其能够在周围神经系统的神经元中形成潜伏感染，由此可以重新激活以引起复发性疾病。我们的长期目标是了解有助于建立HSV-1潜伏期的细胞反应，特别是在神经元中。潜伏基因组在宿主的一生中持续处于附加体染色质化状态，而没有可检测的蛋白质表达。再激活可以自发发生，也可以由各种形式的压力诱导。病毒立即早期蛋白ICP 0是一种多功能蛋白质，对于刺激裂解周期的启动以及潜伏或静止基因组的有效再激活非常重要。ICP 0如何在裂解复制过程中创造有利的细胞环境并促进潜伏期的再激活尚不清楚，但对ICP 0中RING指结构域的E3泛素连接酶活性的依赖性表明涉及其底物的降解。我们的实验室和其他实验室已经表明，HSV-1感染激活并利用细胞DNA损伤信号级联的各个方面。我们还表明，DNA损伤机制可以作为一种内在的细胞防御，通过ICP 0降解特定的DNA修复蛋白而失活。我们的中心假设是，DNA损伤反应和ICP 0的行为在神经元细胞中是不同的，并且这两个因素有助于建立神经元特异性的潜伏期。本提案的目的是确定在感染的最早阶段，DNA损伤反应在传入病毒基因组上的环化和核小体沉积中的作用，并确定这如何影响在神经元中形成裂解或潜伏HSV感染的决定。我们将研究ICP 0如何控制这些过程，并将确定为什么ICP 0蛋白不积累在受感染的神经元的细胞核中。该方法将采用新技术来确定细胞反应如何影响培养物和动物模型中人类神经元的感染。这些神经病毒学研究是重要的，因为它们有望提供对HSV-1感染过程中病毒-宿主相互作用以及决定神经元和非神经元细胞感染结果的早期反应的见解。HSV-1神经潜伏期的知识将为开发针对这种重要的人类病原体的抗病毒药物提供新的靶点。

DESCRIPTION (provided by applicant): Herpes Simplex Virus type 1 (HSV-1) is a human DNA virus that causes a number of diseases involving the human nervous system, including keratitis and encephalitis. The virus is characterized by its ability to form latent infections in neurons of the peripheral nervous system, from which it can reactivate to cause recurrent disease. Our long-term goal is to understand the cellular responses that contribute to establishment of HSV-1 latency specifically in neurons. The latent genome persists in an episomal chromatinized state for the lifetime of the host without detectable protein expression. Reactivation can occur spontaneously or be induced by various forms of stress. The viral immediate early protein ICP0 is a multifunctional protein important for stimulating the initiation f the lytic cycle and also efficient reactivation of latent or quiescent genomes. Exactly how ICP0 creates a favorable cellular environment during lytic replication and promotes reactivation from latency remains unclear, but dependence on the E3 ubiquitin ligase activity of the RING finger domain in ICP0 suggests that degradation of its substrates is involved. Our labs and others have shown that HSV-1 infection activates and exploits aspects of the cellular DNA damage signaling cascade. We have also shown that the DNA damage machinery can act as an intrinsic cellular defense that is inactivated through degradation of specific DNA repair proteins by ICP0. Our central hypothesis is that both the DNA damage response and the behavior of ICP0 are different in neuronal cells, and that these two factors contribute to establishment of latency specifically in neurons. The objective of this proposal is to define the role of the DNA damage response in circularization and nucleosome deposition on the incoming viral genome at the earliest stages of infection, and to determine how this impacts the decision to form lytic or laten HSV infections in neurons. We will examine how ICP0 controls these processes and will determine why the ICP0 protein does not accumulate in the nucleus of infected neurons. The approach will employ novel techniques to determine how cellular responses impact infection in human neurons in culture and in animal models. These neurovirological studies are significant because they are expected to provide insights into virus-host interactions during HSV-1 infection and the early responses that determine the outcome of infection in neurons and non-neuronal cells. Knowledge of HSV-1 neuronal latency will suggest novel targets for developing antivirals against this significant human pathogen.