Imbert J, Lawrence J J, Coulier F, Jeunet E, Billotey V, Birg F
EMBO J. 1984 Nov;3(11):2587-91. doi: 10.1002/j.1460-2075.1984.tb02178.x.
SV40-transformed FR 3T3 rat cells were previously shown to exhibit different patterns of accumulation of the virus-coded T-antigen. One group of transformants accumulates T-antigen throughout the cell cycle, whereas in another group, only the cells in the G2 phase of the cell cycle are stained by immunofluorescence with anti-T antigen antibodies. We investigated the mechanism involved by determining the amounts of early SV40 RNA during the cell cycle. Cells in the various phases of the cell cycle were sorted from an asynchronously growing population using a flow cytofluorimeter. Determination of the amounts of viral RNA in the different nuclear and cytoplasmic RNA fractions showed that in transformants with a G2-restricted accumulation of T-antigen, viral RNA was present in G2, to some extent in S, but could not be detected in cells in G1. In contrast, equivalent amounts of viral RNA were detected in all the phases of the cell cycle in the other group of transformants. Cell sorting, performed after pulse-labeling the cells for 2 h with [35S]methionine, confirmed that translation of the viral mRNAs occurred only in G2 in the first group of transformants, and throughout the cell cycle in the second group.
先前已表明，SV40转化的FR 3T3大鼠细胞表现出病毒编码的T抗原的不同积累模式。一组转化体在整个细胞周期中积累T抗原，而在另一组中，只有处于细胞周期G2期的细胞能用抗T抗原抗体通过免疫荧光染色。我们通过测定细胞周期中早期SV40 RNA的量来研究其中涉及的机制。使用流式细胞荧光仪从异步生长的群体中分离出处于细胞周期不同阶段的细胞。对不同核RNA和细胞质RNA组分中病毒RNA量的测定表明，在T抗原积累受G2期限制的转化体中，病毒RNA存在于G2期，在S期有一定程度的存在，但在G1期细胞中无法检测到。相比之下，在另一组转化体的细胞周期所有阶段都检测到等量的病毒RNA。在用[35S]甲硫氨酸对细胞进行2小时脉冲标记后进行的细胞分选证实，第一组转化体中病毒mRNA的翻译仅发生在G2期，而第二组在整个细胞周期中都有翻译。
