Tiercy J M, Weil R
Eur J Biochem. 1983 Mar 1;131(1):47-55. doi: 10.1111/j.1432-1033.1983.tb07230.x.
Transition of 3T3 mouse fibroblasts from a quiescent to a growing state was induced by the addition of 10% fresh bovine serum to the culture medium. The number of DNA-synthesizing cells began to increase 10-11 h after the addition of serum and reached a maximum of 70-80% around 24 h. In quiescent cells, maintained in 0.5% serum, residual RNA synthesis represented mainly nucleoplasmic transcription (hnRNA, 5-S RNA and tRNA). Synthesis of tRNA was 2-3-fold increased by 1-2 h after addition of serum; however, a significant stimulation of hnRNA, 5-S RNA and 45-S pre-rRNA synthesis could only be observed around 4h. The experimental data also revealed a close temporal relationship between the onset of serum-stimulated hnRNA and overall protein synthesis. Determined colorimetrically, the cellular RNA and protein content began to increase by 4-5 h and had doubled by 24 h. Virtually the same results on RNA and protein synthesis were obtained when the experiments were performed in the presence of cytosine arabinoside, an inhibitor of DNA synthesis. From our results we concluded that serum-stimulated overall RNA and protein synthesis preceded by several hours serum-induced S phase and was independent of DNA replication.
向培养基中添加10%新鲜牛血清可诱导3T3小鼠成纤维细胞从静止状态转变为生长状态。添加血清后10 - 11小时，DNA合成细胞数量开始增加，约24小时时达到最大值70 - 80%。在含有0.5%血清的静止细胞中，残留的RNA合成主要代表核质转录（核不均一RNA、5 - S RNA和转运RNA）。添加血清后1 - 2小时，转运RNA的合成增加了2 - 3倍；然而，只有在大约4小时时才能观察到核不均一RNA、5 - S RNA和45 - S前体核糖体RNA合成的显著刺激。实验数据还揭示了血清刺激的核不均一RNA起始与总体蛋白质合成之间密切的时间关系。通过比色法测定，细胞RNA和蛋白质含量在4 - 5小时开始增加，到24小时时增加了一倍。当在DNA合成抑制剂阿糖胞苷存在的情况下进行实验时，在RNA和蛋白质合成方面获得了几乎相同的结果。从我们的结果中我们得出结论，血清刺激的总体RNA和蛋白质合成比血清诱导的S期提前数小时，并且独立于DNA复制。
