TRANSLATIONAL CONTROL OF CYTOMEGALOVIRUS GENE EXPRESSION

本研究的目的是描述顺式作用信号，识别反式作用因子，并阐明在翻译水平上调节人巨细胞病毒(CMV)基因表达的机制。对CMV翻译控制的分子基础的研究将揭示病毒特有的过程，这可能有助于作为抗病毒干预的靶标，以及对真核溶解翻译的基本原理的新见解。本项目的重点是CMV gpUL4蛋白，其合成受gpUL4 mRNA中的一个短上游开放阅读框架(UORF2)调控。突变病毒将被用来评估uORF2改变对gpUL4表达调控和病毒复制的影响。结合对异位gpUL4后果的研究，这些研究将阐明gpUL4翻译调控在病毒生命周期中的重要性。第二系列实验将阐明uORF2调控基因表达的详细分子机制。利用S.cerevisaie进行的遗传学研究，辅之以哺乳动物细胞和细胞提取物中的分子生物学和生化分析，将描绘由uORF2控制的翻译终止过程中的准确步骤，并将识别参与这一特殊调控机制的反式作用因子。

The goals of this research are to delineate the cis-acting signals, identify the trans-acting factors and elucidate the mechanisms that regulate human cytomegalovirus (CMV) gene expression at the translational level. Investigations of the molecular basis of CMV translational control will reveal both viral-specific processes, potentially useful as targets for antiviral interventions, as well as new insights into fundamentals of eukayrotic translation. This project focuses on the CMV gpUL4 protein, synthesis of which is regulated by a short upstream open reading frame (uORF2) in the gpUL4 mRNA. Mutant viruses will be used to evaluate the effects of uORF2 alterations on regulation of gpUL4 expression and on viral replication. In conjunction with investigations of the consequences of ectopic gpUL4, these studies will illuminate the significance of gpUL4 translational regulation in the viral life cycle. A second series of experiments will elucidate the detailed molecular mechanism by which uORF2 regulates gene expression. Genetic studies using S. cerevisaie, complemented by molecular biological and biochemical assays in mammalian cells and cell extracts will delineate the precise step during translation termination that is controlled by uORF2 and will identify trans-acting factors that participate in this extraordinary regulatory mechanism.