Translational Control of Cytomegalovirus Gene Expression

描述(申请人提供)：这项研究的长期目标是阐明在翻译水平上调节人类巨细胞病毒(HCMV)基因表达的机制。被HCMV感染的细胞继续合成蛋白质，尽管激活了旨在关闭翻译从而阻止病毒复制的宿主机制。这些研究将阐明在HCMV感染的细胞中保持强大的蛋白质合成能力的生化和遗传学基础。HCMV挽救了缺少双链RNA结合蛋白基因E3L(VVdeltaE3L)的痘苗病毒突变体的复制。在没有HCMV的情况下，感染VVdeltaE3L的细胞含有高水平的磷酸化eIF2-α和RNASE活性，以及低水平的蛋白质合成、病毒晚期基因表达和病毒产量。巨细胞病毒感染会逆转这些特性中的每一个。使用VVdeltaE3L作为激活宿主细胞抗病毒反应的手段，实验将描绘导致eIF2-α磷酸化和RNASEL激活的通路中被HCMV感染阻断的步骤。负责挽救VVdeltaE3L晚期基因表达和复制的巨细胞病毒基因(S)将被鉴定并划定其功能结构域。补充基因(S)的作用机制将被阐明，其表达特性、不同毒株之间的保守性以及在复制周期中的作用将被确定。这些研究将揭示宿主-病毒相互作用的新见解，这些相互作用可能是巨细胞病毒病发病机制的关键决定因素。

DESCRIPTION (provided by applicant): The long-range goals of this research are to elucidate mechanisms that regulate human cytomegalovirus (HCMV) gene expression at the translational level. Cells infected by HCMV continue to synthesize proteins, despite activation of host mechanisms designed to shut off translation and thereby prevent viral replication. These studies will clarify the biochemical and genetic basis for the preservation of the robust protein synthetic capacity in HCMV-infected cells. HCMV rescues replication of a vaccinia virus mutant lacking the double-stranded RNA binding protein gene E3L (VVdeltaE3L). In the absence of HCMV, cells infected with the VVdeltaE3L contain high levels of phosphorylated eIF2-alpha and RNaseL activity, and low levels of protein synthesis, viral late gene expression and viral production. HCMV infection reverses each of these properties. Using VVdeltaE3L as a means to activate the host cell antiviral responses, experiments will delineate the steps in the pathways leading to eIF2-alpha phosphorylation and RNaseL activation that are blocked by HCMV infection. The HCMV gene(s) responsible for the rescue of late gene expression and replication of VVdeltaE3L will be identified and its functional domains will be delineated. The mechanism of action of the complementing gene(s) will be elucidated and its expression properties, conservation among HCMV isolates and role in the replicative cycle will be determined. These studies will reveal new insights into the host-virus interactions that are likely to be critical determinants of the pathogenesis of HCMV disease.