Pericentric chromatin is an elastic component of the mitotic spindle
Pericentric chromatin is an elastic component of the mitotic spindle
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DOI：
10.1016/j.cub.2007.03.033
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发表时间：
2007-05-01
期刊：
影响因子：
9.2
通讯作者：
Bloom, Kerry
中科院分区：
文献类型：
--
作者：
Bouck, David C.;Bloom, Kerry
背景：在染色体分离之前，有丝分裂纺锤体使姐妹染色单体沿着中期板双向排列。在中期，纺锤体长度保持不变，这表明纺锤体力（向内和向外）是平衡的。微管马达、微管动力学调节剂和粘附素对纺锤体稳定性的贡献以前已经被研究过。在这项研究中，我们研究了染色质结构的贡献动粒定位和纺锤体长度的控制。核小体耗尽后，无论是组蛋白H3或H4镇压，纺锤体组织进行了检查，通过活细胞荧光microscopic.Results：组蛋白镇压导致姐妹着丝粒分离的2倍增加，并在中期纺锤体长度相等的增加。组蛋白H3的抑制不损害动粒，而H4的抑制破坏适当的动粒功能。删除向外的力发生器，驱动蛋白Cin8p和Kip1p，缩短了长纺锤体观察组蛋白抑制细胞。振荡运动的个别姐妹染色单体对组蛋白repression.Conclusions后没有改变：增加纺锤体长度后组蛋白阻遏和恢复野生型纺锤体长度的损失，加上端定向电机表明，在中期，着丝粒分离和纺锤体长度部分由臂间染色质的拉伸。染色质是一种弹性分子，其拉伸方向与向外的力发生器Cin8p和Kip1p相反。因此，我们分配一个新的角色，染色质包装作为一个不可分割的生物物理组成部分的有丝分裂装置。
Background: Prior to chromosome segregation, the mitotic spindle bi-orients and aligns sister chromatids along the metaphase plate. During metaphase, spindle length remains constant, which suggests that spindle forces (inward and outward) are balanced. The contribution of microtubule motors, regulators of microtubule dynamics, and cohesin to spindle stability has been previously studied. In this study, we examine the contribution of chromatin structure on kinetochore positioning and spindle-length control. After nucleosome depletion, by either histone H3 or H4 repression, spindle organization was examined by live-cell fluorescence microscopy.Results: Histone repression led to a 2-fold increase in sister-centromere separation and an equal increase in metaphase spindle length. Histone H3 repression does not impair kinetochores, whereas H4 repression disrupts proper kinetochore function. Deletion of outward force generators, kinesins Cin8p and Kip1p, shortens the long spindles observed in histone-repressed cells. Oscillatory movements of individual sister chromatid pairs are not altered after histone repression.Conclusions: The increase in spindle length upon histone repression and restoration of wild-type spindle length by the loss of plus-end-directed motors suggests that during metaphase, centromere separation and spindle length are governed in part by the stretching of pericentric chromatin. Chromatin is an elastic molecule that is stretched in direct opposition to the outward force generators Cin8p and Kip1p. Thus, we assign a new role to chromatin packaging as an integral biophysical component of the mitotic apparatus.