Nilsen T W, Maroney P A, Baglioni C
J Biol Chem. 1982 Dec 25;257(24):14593-6.
Protein synthesis was inhibited in one line of interferon-treated HeLa cells (line 2) upon infection with reovirus, but not in different HeLa cells (line 1) treated in the same way. The inhibition resulted in polysome runoff, suggesting that it was due to an impairment of peptide chain initiation. Interferon induces the synthesis of a protein kinase, which is activated in cell-free systems by double-stranded RNA and phosphorylates the alpha subunit of eukaryotic initiation factor 2, thus inhibiting the initiation of protein synthesis. Therefore, we measured the level of this protein kinase in extracts prepared from the two HeLa cell lines. Cells of line 2 showed about 3-4 times more protein kinase activity than cells of line 1. The inhibition of protein synthesis upon infection with reovirus was correlated with an increased phosphorylation of the alpha subunit of eukaryotic initiation factor 2 in interferon-treated cells labeled with 32P. The kinase was presumably activated in intact cells by viral double-stranded RNA, but this activation resulted in inhibition of protein synthesis only in cells with elevated levels of the kinase.
在用呼肠孤病毒感染时，干扰素处理过的一组海拉细胞系（2系）中的蛋白质合成受到抑制，但同样处理的不同海拉细胞系（1系）中却未受抑制。这种抑制导致多核糖体解聚，提示其原因在于肽链起始的损伤。干扰素诱导一种蛋白激酶的合成，该激酶在无细胞体系中被双链RNA激活，并使真核起始因子2的α亚基磷酸化，从而抑制蛋白质合成的起始。因此，我们测定了从这两个海拉细胞系制备的提取物中这种蛋白激酶的水平。2系细胞显示出的蛋白激酶活性比1系细胞高约3至4倍。在用32P标记的干扰素处理的细胞中，感染呼肠孤病毒后蛋白质合成的抑制与真核起始因子2的α亚基磷酸化增加相关。该激酶可能在完整细胞中被病毒双链RNA激活，但这种激活仅在激酶水平升高的细胞中导致蛋白质合成的抑制。
