Synchronizing chromosome segregation by flux-dependent force equalization at kinetochores
Synchronizing chromosome segregation by flux-dependent force equalization at kinetochores
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DOI：
10.1083/jcb.200904153
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发表时间：
2009-07-13
影响因子：
7.8
通讯作者：
Maiato, Helder
中科院分区：
文献类型：
--
作者：
Matos, Irina;Pereira, Antonio J.;Maiato, Helder
后期染色体的同步运动保证了每次细胞分裂时染色体的正确遗传。这反映了作用在染色体上的纺锤体力的均匀性和它们同时进入后期。虽然后期的开始是由纺锤体组装检查点控制的，但纺锤体力如何均匀分布在不同的染色体上仍然是未知的。在这篇论文中，我们发现纺锤体微管通量促进了果蝇S2细胞中期着丝点的张力均匀性和随后的后期同步。这些结果可以用纺锤体的力学模型来解释，在纺锤体中，与通量相关的微管向两极移位事件反映了着丝点微管界面的松弛，这解释了着丝点张力在与典型中期持续时间相当的时间尺度上的重新分配和收敛。正如模型所预测的那样，有丝分裂的实验加速排除了张力均衡和后期同步。我们提出，通量依赖的着丝点张力均衡确保了着丝点-微管界面的及时和均匀成熟，这是后期染色体无差错和协调分离所必需的。
The synchronous movement of chromosomes during anaphase ensures their correct inheritance in every cell division. This reflects the uniformity of spindle forces acting on chromosomes and their simultaneous entry into anaphase. Although anaphase onset is controlled by the spindle assembly checkpoint, it remains unknown how spindle forces are uniformly distributed among different chromosomes. In this paper, we show that tension uniformity at metaphase kinetochores and subsequent anaphase synchrony in Drosophila S2 cells are promoted by spindle microtubule flux. These results can be explained by a mechanical model of the spindle where microtubule poleward translocation events associated with flux reflect relaxation of the kinetochore microtubule interface, which accounts for the redistribution and convergence of kinetochore tensions in a timescale comparable to typical metaphase duration. As predicted by the model, experimental acceleration of mitosis precludes tension equalization and anaphase synchrony. We propose that flux-dependent equalization of kinetochore tensions ensures a timely and uniform maturation of kinetochore-microtubule interfaces necessary for error-free and coordinated segregation of chromosomes in anaphase.