Ornelles D A, Fey E G, Penman S
Mol Cell Biol. 1986 May;6(5):1650-62. doi: 10.1128/mcb.6.5.1650-1662.1986.
Cytochalasin D was shown to be a reversible inhibitor of protein synthesis in HeLa cells. The inhibition was detectable at drug levels typically used to perturb cell structure and increased in a dose-dependent manner. The drug also released mRNA from the cytoskeletal framework in direct proportion to the inhibition of protein synthesis. The released mRNA was unaltered in its translatability as measured in vitro but was no longer translated in the cytochalasin-treated HeLa cells. The residual protein synthesis occurred on polyribosomes that were reduced in amount but displayed a normal sedimentation distribution. The results support the hypothesis that mRNA binding to the cytoskeletal framework is necessary although not sufficient for translation. Analysis of the cytoskeletal framework, which binds the polyribosomes, revealed no alterations in composition or amount of protein as a result of treatment with cytochalasin D. Electron microscopy with embedment-free sections shows the framework in great detail. The micrographs revealed the profound reorganization effected by the drug but did not indicate substantial disaggregation of the cytoskeletal elements.
细胞松弛素D被证明是HeLa细胞中蛋白质合成的可逆抑制剂。在通常用于扰乱细胞结构的药物水平下即可检测到抑制作用，且呈剂量依赖性增加。该药物还以与蛋白质合成抑制成正比的比例从细胞骨架框架中释放出mRNA。释放出的mRNA在体外测量时其可翻译性未改变，但在经细胞松弛素处理的HeLa细胞中不再被翻译。残留的蛋白质合成发生在数量减少但沉降分布正常的多核糖体上。这些结果支持了这样一种假说，即mRNA与细胞骨架框架的结合对于翻译是必要的，尽管并不充分。对结合多核糖体的细胞骨架框架的分析表明，用细胞松弛素D处理后，其蛋白质组成或数量没有改变。使用无包埋切片的电子显微镜能非常详细地显示该框架。显微照片揭示了药物引起的深刻重组，但未表明细胞骨架成分有大量解聚。
