Stenberg R M, Depto A S, Fortney J, Nelson J A
Department of Microbiology, West Virginia University Health Sciences Center, Morgantown 26506.
J Virol. 1989 Jun;63(6):2699-708. doi: 10.1128/JVI.63.6.2699-2708.1989.
Expression of RNA and protein from the human cytomegalovirus immediate-early (IE) gene region (map units 0.732 to 0.751) was analyzed at early and late times after infection. The level of RNA present at late times (48 to 72 h after infection) was significantly higher than that present at IE times (5 h after infection). The profile of IE RNA in the cytoplasm of infected cells was different from that previously reported on polysomes (R. M. Stenberg, P. R. Witte, and M. F. Stinski, J. Virol. 56:665-675, 1985). The data indicate that the 1.95-kilobase (kb) major IE region 1 mRNA, which codes for the 72-kilodalton (kDa) protein, and the 1.7-kb IE region 2 (IE2) spliced mRNA, which codes for the IE2 55-kDa protein, may be preferentially associated with polysomes. However, the IE2 2.2-kb unspliced mRNA, which codes for an 86-kDa protein, may be preferentially excluded. This RNA was abundant in the cytoplasm under IE conditions but was not present on polysomes in significant quantities. This indicates that IE gene products may be involved in translational control of cytomegalovirus RNA. At late times, new transcription takes place within region 2. A 1.5-kb RNA is transcribed from a late promoter in region 2 that apparently does not function in cells infected with DNA-negative mutant ts66. These results demonstrate that the IE gene region is transcribed throughout infection and that multiple levels of regulation exist.
在感染后的早期和晚期，对人巨细胞病毒立即早期（IE）基因区域（图谱单位0.732至0.751）的RNA和蛋白质表达进行了分析。晚期（感染后48至72小时）存在的RNA水平显著高于IE期（感染后5小时）存在的RNA水平。感染细胞细胞质中IE RNA的分布情况与先前在多核糖体上报道的不同（R.M.斯滕伯格、P.R.威特和M.F.斯廷斯基，《病毒学杂志》56:665 - 675，1985）。数据表明，编码72千道尔顿（kDa）蛋白质的1.95千碱基（kb）主要IE区域1 mRNA，以及编码IE2 55-kDa蛋白质的1.7-kb IE区域2（IE2）剪接mRNA，可能优先与多核糖体相关联。然而，编码86-kDa蛋白质的IE2 2.2-kb未剪接mRNA可能被优先排除。这种RNA在IE条件下的细胞质中丰富，但在多核糖体上数量不多。这表明IE基因产物可能参与了巨细胞病毒RNA的翻译控制。在晚期，区域2内发生新的转录。从区域2中的一个晚期启动子转录出一种1.5-kb RNA，该启动子在感染DNA阴性突变体ts66的细胞中显然不起作用。这些结果表明，IE基因区域在整个感染过程中都有转录，并且存在多种调控水平。
