Wathen M W, Thomsen D R, Stinski M F
J Virol. 1981 May;38(2):446-59. doi: 10.1128/JVI.38.2.446-459.1981.
The immediate early transcripts of human cytomegalovirus originated from restricted regions of the viral genome. In contrast, transcription at early times was complementary to all regions of the viral genome that were fractionated by restriction endonuclease treatment followed by agarose gel electrophoresis. The viral genome was also extensively transcribed when 2 h of protein synthesis or longer was permitted after infection in permissive cells treated with an inhibitor of viral DNA replication or in nonpermissive cells of animal origin that permit little or no viral DNA replication. The size and in vitro translation products of the cytomegalovirus-specified mRNA's at immediate early and early times after infection were determined. Discrete size classes of virus-specified polyadenylated RNA accumulated on the polyribosomes of cells infected in the presence of an inhibitor of protein synthesis. When 2 or 24 h of protein synthesis occurred after infection, there were changes in the relative abundance of the virus-specified RNAs that accumulated on polyribosomes. Treatment of nonpermissive cells had little effect on the size classes of viral RNA found associated with the polyribosomes at early times after infection. These viral mRNA's were assumed to represent early viral gene expression. In vitro translation of the viral mRNA isolated from polyribosomes at immediate early and early times after infection identified many of the virus-specified gene products and demonstrated (i) a switch from immediate early to early viral gene expression and (ii) a prolonged phase of early viral gene expression. The data also indicated that the initiation of viral RNA synthesis does not depend on the formation of viral protein, but that de novo viral protein synthesis may influence the extent of transcription of the viral genome.
人类巨细胞病毒的即刻早期转录本源自病毒基因组的特定区域。相比之下，早期转录与病毒基因组的所有区域互补，这些区域经限制性内切酶处理后再通过琼脂糖凝胶电泳进行分离。在用病毒DNA复制抑制剂处理的允许性细胞中感染后，或在几乎不发生或不发生病毒DNA复制的动物源性非允许性细胞中感染后，若允许2小时或更长时间的蛋白质合成，病毒基因组也会大量转录。测定了感染后即刻早期和早期巨细胞病毒特异性mRNA的大小及体外翻译产物。在存在蛋白质合成抑制剂的情况下感染的细胞的多核糖体上，积累了不同大小类别的病毒特异性多聚腺苷酸化RNA。感染后若发生2小时或24小时的蛋白质合成，多核糖体上积累的病毒特异性RNA的相对丰度会发生变化。在感染后早期，处理非允许性细胞对与多核糖体相关的病毒RNA大小类别影响不大。这些病毒mRNA被认为代表早期病毒基因表达。对感染后即刻早期和早期从多核糖体分离的病毒mRNA进行体外翻译，鉴定出许多病毒特异性基因产物，并证明了（i）从即刻早期病毒基因表达向早期病毒基因表达的转变，以及（ii）早期病毒基因表达的延长阶段。数据还表明，病毒RNA合成的起始不依赖于病毒蛋白的形成，但病毒蛋白的从头合成可能会影响病毒基因组的转录程度。
