Geballe A P, Leach F S, Mocarski E S
J Virol. 1986 Mar;57(3):864-74. doi: 10.1128/JVI.57.3.864-874.1986.
We investigated the control of human cytomegalovirus (CMV) late (gamma)-gene expression in human fibroblast cells. Transcriptional activity of two gamma genes, encoding ICP27, a structural component (matrix or tegument) of virions, and ICP36, a major DNA-binding protein family, was followed by analysis of steady-state RNA levels during viral infection. Synthesis of the protein products of these genes was analyzed with specific monoclonal antibodies in conjunction with sensitive immunoblot or immunoprecipitation analysis. Although accumulation of ICP27 and ICP36 was not abundant until late times, both late genes were as transcriptionally active at early times (4 h postinfection) as at late times (48 h postinfection). Reduced amounts (less than 5% of late levels) of the protein products were detected at early times, demonstrating that a small proportion of the ICP27 and ICP36 RNA made at this time was translated. These observations establish that expression of at least two CMV gamma genes is regulated through posttranscriptional events. The very early transcriptional activation of late genes and the relative importance of posttranscriptional regulation to late-gene expression distinguishes CMV from other well-studied herpesviruses and does not appear analogous to late-gene regulation in any other DNA animal virus.
我们研究了人巨细胞病毒（CMV）晚期（γ）基因在人成纤维细胞中的表达调控。通过分析病毒感染期间的稳态RNA水平，跟踪了两个γ基因的转录活性，这两个基因分别编码病毒体的结构成分（基质或包膜）ICP27和主要的DNA结合蛋白家族ICP36。使用特异性单克隆抗体结合灵敏的免疫印迹或免疫沉淀分析，对这些基因的蛋白质产物合成进行了分析。尽管ICP27和ICP36的积累直到晚期才丰富起来，但这两个晚期基因在早期（感染后4小时）和晚期（感染后48小时）的转录活性是一样的。在早期检测到的蛋白质产物量减少（不到晚期水平的5%），表明此时产生的一小部分ICP27和ICP36 RNA被翻译了。这些观察结果表明，至少两个CMVγ基因的表达是通过转录后事件调控的。晚期基因的极早期转录激活以及转录后调控对晚期基因表达的相对重要性，使CMV有别于其他经过充分研究的疱疹病毒，并且在任何其他DNA动物病毒中似乎都不存在类似的晚期基因调控情况。
