Control of Translation in Herpesvirus Infected Cells

在翻译水平上调节基因表达对于控制细胞的正常生长、发育、分化、学习、记忆以及对环境胁迫，包括病毒感染的反应是至关重要的。特别是，许多真核细胞有帽的、多腺化的mRNAs的翻译在起始步骤受到控制，在这个步骤中，需要一个专门的多蛋白复合体的受调控的组装，以将小的核糖体亚基招募到mRNA5‘末端。该复合体的翻译起始因子组分能够对不同的细胞信号级联反应，从而对不同的生理效应器做出快速反应。病毒模型系统已被证明在阐述细胞翻译控制策略方面特别有用，因为它们的成功复制绝对需要病毒mRNA的翻译。在捕获和参与细胞蛋白质合成机制的持续努力中，病毒必须有效地控制调节翻译的细胞信号级联。本研究以疱疹病毒家族成员人巨细胞病毒(HCMV)为探针，探索调控mRNA翻译起始的复杂回路。虽然对大多数健康人无害，但HCMV是一种广泛存在的机会性病原体，在免疫功能受损的人中会导致严重疾病，包括骨髓和实体器官移植接受者以及艾滋病患者。此外，先天性巨细胞病毒感染是导致新生儿出生缺陷的主要病毒原因。我们的长期总体目标是了解HCMV是如何操纵细胞翻译控制通路的，以确保病毒mRNAs能够有效地与细胞mRNAs竞争获得翻译起始因子。由于这一过程对于有效复制和从潜伏期重新激活至关重要，我们的研究可能会揭示干扰病毒复制的新目标，以及创造对疫苗开发有用的减弱、减毒株的新策略。此外，这些研究将提供对翻译控制的基本机制的洞察，这些机制可能在许多人类疾病中被证明是重要的，包括癌症和糖尿病，在这些疾病中，蛋白质产生的调节是异常的。我们特别建议：1)确定巨细胞病毒感染如何影响eIF4F核心和相关成分；2)确定在巨细胞病毒感染的细胞中PABP丰度被翻译控制的机制(S)；以及3)评估细胞内eIF4E-激酶和eIF4E磷酸化在病毒复制和致病中的作用

Regulation of gene expression at the level of translation is fundamentally important for the control of normal cell growth, development, differentiation, learning, memory, and the response to environmental stress, including viral infection. In particular, the translation of many eukaryotic capped, polyadenylated mRNAs is controlled at the initiation step, where the regulated assembly of a specialized, multiprotein complex is required to recruit the small ribosome subunit to the mRNA 5' terminus. The translation initiation factor components of this complex are capable of responding to different cellular signaling cascades, enabling a rapid response to diverse physiological effectors. Viral model systems have proven to be particularly useful in elaborating cellular translational control strategies because their successful replication absolutely requires viral mRNA translation. In their continued efforts to capture and engage the cellular protein synthesis machinery, viruses must effectively control the cellular signaling cascades that regulate translation. This investigation utilizes a herpes virus family member, human cytomegalovirus (HCMV), as a probe to explore the complex circuitry regulating the initiation of mRNA translation. Although innocuous in most healthy individuals, HCMV is a widespread, opportunistic pathogen responsible for severe disease among the immunocompromised, including bone marrow and solid organ transplant recipients along with AIDS patients. In addition, congenital HCMV infection is the leading viral cause of birth defects in newborns. Our long-term overall objective is to understand how HCMV manipulates cellular translational control pathways to ensure that viral mRNAs can compete effectively with cellular mRNAs for access to translation initiation factors. As this process is critical for productive replication and reactivation from latency, our investigation is likely to reveal new targets for interfering with viral replication and new strategies for creating weakened, attenuated strains useful for vaccine development. In addition, these studies will provide insight into basic mechanisms of translational control that are likely to prove important in many human diseases, including cancer and diabetes, where the regulation of protein production is abnormal. We specifically propose to i) determine how HCMV infection affects eIF4F-core and associated components; ii) define the mechanism(s) by which PABP abundance is controlled translationally in HCMV-infected cells; and iii) evaluate the role of cellular eIF4E-kinases & eIF4E phosphorylation on viral replication & pathogenesis