Simultaneous cytoplasmic redistribution of ribosomal protein L32 mRNA and phosphorylation of eukaryotic initiation factor 4E after mitogenic stimulation of Swiss 3T3 cells.
Simultaneous cytoplasmic redistribution of ribosomal protein L32 mRNA and phosphorylation of eukaryotic initiation factor 4E after mitogenic stimulation of Swiss 3T3 cells.
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DOI：
10.1016/s0021-9258(19)39637-1
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发表时间：
1990-03
期刊：
影响因子：
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通讯作者：
R. Kaspar;W. Rychlik;M. White;R. Rhoads;D. Morris
中科院分区：
文献类型：
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作者：
R. Kaspar;W. Rychlik;M. White;R. Rhoads;D. Morris
静止的 Swiss 3T3 细胞的血清激活后，核糖体蛋白 L32 mRNA 从信使核糖核蛋白颗粒转移到多聚核糖体中。 mRNA 重新分布到翻译活性状态在激活后 1 小时开始，并在 3 小时完成。相比之下，肌动蛋白 mRNA 没有表现出翻译控制，主要存在于静止和激活培养物的多核糖体中。平行检查了结合 mRNA 帽的真核起始因子 (eIF) 4E 的磷酸化状态。 eIF-4E 磷酸化在血清激活后 1 小时升高，并在 3-5 小时达到峰值。用佛波酯处理静息细胞也同时刺激 eIF-4E 磷酸化和 L32 mRNA 移动到多聚核糖体中。这些结果与丝裂原诱导的磷酸化增加了活性 eIF-4E 分子库的模型一致，这反过来又导致翻译控制的 mRNA 被募集以主动合成核糖体。
Ribosomal protein L32 mRNA moved from messenger ribonucleoprotein particles into polysomes following serum activation of quiescent Swiss 3T3 cells. This redistribution of the mRNA into a translationally active state began by 1 h and was complete by 3 h after activation. In contrast, actin mRNA showed no translational control, being found predominantly in polysomes in both quiescent and activated cultures. The phosphorylation state of eukaryotic initiation factor (eIF) 4E, which binds mRNA caps, was examined in parallel. eIF-4E phosphorylation was elevated by 1 h following serum activation and reached a peak by 3-5 h. Treatment of resting cells with phorbol ester also simultaneously stimulated eIF-4E phosphorylation and the movement of L32 mRNA into polysomes. These results are consistent with a model in which mitogen-induced phosphorylation increases the pool of active eIF-4E molecules, which in turn cause the recruitment of translationally controlled mRNAs to actively synthesizing ribosomes.