Belmont L D, Hyman A A, Sawin K E, Mitchison T J
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Cell. 1990 Aug 10;62(3):579-89. doi: 10.1016/0092-8674(90)90022-7.
Using Xenopus egg extracts arrested in interphase or mitosis, we directly observed differences in microtubule dynamics at different stages of the cell cycle. Interphase extracts were prepared from eggs in the first interphase after meiosis. Mitotic extracts were prepared by addition of purified cyclin to interphase extracts. Microtubules were nucleated by the addition of centrosomes and visualized by fluorescence video-microscopy in extracts to which rhodamine-labeled tubulin had been added. We found a striking difference in microtubule dynamics in mitotic versus interphase extracts. Quantitative analysis revealed that the rates of polymerization and depolymerization are similar in interphase and mitosis and that within the spatial and temporal resolution of our experiments the difference in dynamics is due almost entirely to an increase in the frequency of transition from growing to shrinking (catastrophe frequency) in the mitotic extracts.
利用停滞在间期或有丝分裂期的非洲爪蟾卵提取物，我们直接观察到了细胞周期不同阶段微管动力学的差异。间期提取物是从减数分裂后的第一次间期的卵中制备的。有丝分裂提取物是通过向间期提取物中添加纯化的细胞周期蛋白来制备的。通过添加中心体使微管成核，并在添加了罗丹明标记微管蛋白的提取物中通过荧光视频显微镜进行观察。我们发现在有丝分裂提取物与间期提取物中微管动力学存在显著差异。定量分析表明，聚合和解聚速率在间期和有丝分裂期相似，并且在我们实验的空间和时间分辨率范围内，动力学差异几乎完全是由于有丝分裂提取物中从生长到收缩转变的频率增加（灾难频率）所致。
