Translational Control of Cytomegalovirus Gene Expression

描述（由申请人提供）：本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，尽管宿主机制被激活来关闭翻译，从而阻止病毒复制。这些研究将阐明hcmv感染细胞保持强大的蛋白质合成能力的生化和遗传基础。HCMV挽救了缺乏双链RNA结合蛋白基因E3L （VVdeltaE3L）的牛痘病毒突变体的复制。在没有HCMV的情况下，被VVdeltaE3L感染的细胞含有高水平的磷酸化eif2 - α和RNaseL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生。HCMV感染逆转了这些特性。使用VVdeltaE3L作为激活宿主细胞抗病毒反应的手段，实验将描述导致eif2 - α磷酸化和RNaseL激活的途径中的步骤，这些途径被HCMV感染阻断。将确定负责挽救VVdeltaE3L晚期基因表达和复制的HCMV基因，并描绘其功能域。将阐明互补基因的作用机制，并确定其表达特性、在HCMV分离株中的保守性及其在复制周期中的作用。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HCMV疾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.