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腾讯登录Science：有丝分裂过程中动粒的结构变化
| 导读 | 6月21日，<em>Science</em>在线报道了动粒在细胞有丝分裂运动过程中的结构变化的研究进展。
动粒在有丝分裂中调节染色体分离。它们被认为与微管之间既存在主动地产力的相互作用，也存在被动地摩擦的界面。而在这种相互作用中，微管的相对位置一直不清楚。
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通过测量在正进行有丝分裂的活细胞中荧光标记的动粒亚基之间平均距离... |
6月21日，<em>Science</em>在线报道了动粒在细胞有丝分裂运动过程中的结构变化的研究进展。
动粒在有丝分裂中调节染色体分离。它们被认为与微管之间既存在主动地产力的相互作用，也存在被动地摩擦的界面。而在这种相互作用中，微管的相对位置一直不清楚。
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通过测量在正进行有丝分裂的活细胞中荧光标记的动粒亚基之间平均距离，研究者推断在中期振荡过程中单个动粒内存在机械变形。动粒亚基间距离在动粒朝向细胞两极运动时较短，而在背向两极运动时较长。动粒切换到朝向两极方向移动时，其亚基间距离突然下降，并随着拉力增加而进一步减少。这提示，向极方向移动过程中的主动力量压缩着动粒。数据还显示，在动粒内部存在一个主动力的产生界面，和一个距离细胞两极至少20 nm，独立的被动摩擦界面。总之，这些界面导致动粒亚基之间持续的接触和相互作用，这为产生间歇性的主动动力创造了条件。
动粒在有丝分裂中的运动细节的进一步揭示，为研究许多有丝分裂异常相关的重要疾病，如肿瘤，某些染色体核型异常遗传病，提供了重要的参考。
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<img src="http://www.bioon.com/biology/UploadFiles/201206/2012062312203309.gif" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://dx.doi.org/10.1016/j.cell.2011.10.017" target="_blank">doi:</a><a title="" href="http://www.sciencemag.org/content/early/2012/06/20/science.1221886.abstract" target="_blank">10.1016/j.cell.2011.10.017</a>
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<br/><strong>Deformations Within Moving Kinetochores Reveal Different Sites of Active and Passive Force Generation</strong><br/>
Sophie Dumont1,*,?, E. D. Salmon2, Timothy J. Mitchison1
Kinetochores mediate chromosome segregation at mitosis. They are thought to contain both active, force-producing and passive, frictional interfaces with microtubules whose relative locations have been unclear. We inferred mechanical deformation within single kinetochores during metaphase oscillations by measuring average separations between fluorescently labeled kinetochore subunits in living cells undergoing mitosis. Intersubunit distances were shorter in kinetochores moving toward poles than those moving away. Intersubunit separation decreased abruptly when kinetochores switched to poleward movement, and decreased further when pulling force increased, suggesting that active force generation during poleward movement compresses kinetochores. The data revealed an active force-generating interface within kinetochores, and a separate passive frictional interface located at least 20 nm away poleward. Together, these interfaces allow persistent attachment with intermittent active force generation.
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动粒在有丝分裂中调节染色体分离。它们被认为与微管之间既存在主动地产力的相互作用，也存在被动地摩擦的界面。而在这种相互作用中，微管的相对位置一直不清楚。
<!--more-->
通过测量在正进行有丝分裂的活细胞中荧光标记的动粒亚基之间平均距离，研究者推断在中期振荡过程中单个动粒内存在机械变形。动粒亚基间距离在动粒朝向细胞两极运动时较短，而在背向两极运动时较长。动粒切换到朝向两极方向移动时，其亚基间距离突然下降，并随着拉力增加而进一步减少。这提示，向极方向移动过程中的主动力量压缩着动粒。数据还显示，在动粒内部存在一个主动力的产生界面，和一个距离细胞两极至少20 nm，独立的被动摩擦界面。总之，这些界面导致动粒亚基之间持续的接触和相互作用，这为产生间歇性的主动动力创造了条件。
动粒在有丝分裂中的运动细节的进一步揭示，为研究许多有丝分裂异常相关的重要疾病，如肿瘤，某些染色体核型异常遗传病，提供了重要的参考。
<div id="ztload">
<div> </div>
<div>
<div>
<img src="http://www.bioon.com/biology/UploadFiles/201206/2012062312203309.gif" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://dx.doi.org/10.1016/j.cell.2011.10.017" target="_blank">doi:</a><a title="" href="http://www.sciencemag.org/content/early/2012/06/20/science.1221886.abstract" target="_blank">10.1016/j.cell.2011.10.017</a>
PMC:
PMID:
</div>
<div>
<br/><strong>Deformations Within Moving Kinetochores Reveal Different Sites of Active and Passive Force Generation</strong><br/>
Sophie Dumont1,*,?, E. D. Salmon2, Timothy J. Mitchison1
Kinetochores mediate chromosome segregation at mitosis. They are thought to contain both active, force-producing and passive, frictional interfaces with microtubules whose relative locations have been unclear. We inferred mechanical deformation within single kinetochores during metaphase oscillations by measuring average separations between fluorescently labeled kinetochore subunits in living cells undergoing mitosis. Intersubunit distances were shorter in kinetochores moving toward poles than those moving away. Intersubunit separation decreased abruptly when kinetochores switched to poleward movement, and decreased further when pulling force increased, suggesting that active force generation during poleward movement compresses kinetochores. The data revealed an active force-generating interface within kinetochores, and a separate passive frictional interface located at least 20 nm away poleward. Together, these interfaces allow persistent attachment with intermittent active force generation.
</div>
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