Laser microsurgery reveals conserved viscoelastic behavior of the kinetochore.
Laser microsurgery reveals conserved viscoelastic behavior of the kinetochore.
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DOI：
10.1083/jcb.201506011
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发表时间：
2016-03-28
期刊：
影响因子：
--
通讯作者：
Gregan J
中科院分区：
文献类型：
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作者：
Cojoc G;Roscioli E;Zhang L;García-Ulloa A;Shah JV;Berns MW;Pavin N;Cimini D;Tolić IM;Gregan J
本研究为研究动粒的力学反应提供了一种新的实验模型。酵母和哺乳动物细胞的激光显微手术和活细胞成像显示动粒的保守粘弹性反应。正确的染色体分离依赖于适当的着丝粒-微管附着。在微管相互作用时，动粒受到微管产生的力的作用。在这项工作中，我们使用激光烧蚀切断微管附着到merotelic动粒，这是横向拉伸由微管施加的拉力相反，并推断其长度变化的动粒的机械响应。在哺乳动物PtK 1细胞和裂殖酵母裂殖酵母，着丝粒缩短微管切断后。有趣的是，内部的动粒-着丝粒比外部的动粒放松得更快。而在分裂酵母中，所有的动粒都放松到相似的长度，在PtK 1细胞中，伸展的动粒仍然更伸展。简单的模型表明，这些差异的出现是因为哺乳动物动粒的机械结构更加复杂。我们的研究建立了merotelic动粒作为研究活细胞中动粒的机械响应的实验模型，并揭示了在酵母和哺乳动物细胞中保守的动粒的粘弹性行为。
This study establishes merotelic kinetochores as a new experimental model for studying the mechanical response of the kinetochore. Laser microsurgery and live-cell imaging in yeast and mammalian cells show a conserved viscoelastic response of the kinetochore. Accurate chromosome segregation depends on proper kinetochore–microtubule attachment. Upon microtubule interaction, kinetochores are subjected to forces generated by the microtubules. In this work, we used laser ablation to sever microtubules attached to a merotelic kinetochore, which is laterally stretched by opposing pulling forces exerted by microtubules, and inferred the mechanical response of the kinetochore from its length change. In both mammalian PtK1 cells and in the fission yeast Schizosaccharomyces pombe, kinetochores shortened after microtubule severing. Interestingly, the inner kinetochore–centromere relaxed faster than the outer kinetochore. Whereas in fission yeast all kinetochores relaxed to a similar length, in PtK1 cells the more stretched kinetochores remained more stretched. Simple models suggest that these differences arise because the mechanical structure of the mammalian kinetochore is more complex. Our study establishes merotelic kinetochores as an experimental model for studying the mechanical response of the kinetochore in live cells and reveals a viscoelastic behavior of the kinetochore that is conserved in yeast and mammalian cells.