Microtubule Motility on Reconstituted Meiotic Chromatin
Microtubule Motility on Reconstituted Meiotic Chromatin
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DOI：
10.1016/j.cub.2010.02.067
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发表时间：
2010-04-27
期刊：
影响因子：
9.2
通讯作者：
Surrey, Thomas
中科院分区：
文献类型：
--
作者：
Bieling, Peter;Kronja, Iva;Surrey, Thomas
在细胞分裂过程中，染色体在有丝分裂和减数分裂纺锤体中的正确定位取决于微管与着丝点的相互作用，特别是在高等真核生物中，与染色体臂的相互作用[1,2]。染色质激酶高度集中在有丝分裂和减数分裂染色质上，被认为积极地将染色体臂推向纺锤体中心，从而有助于有丝分裂早期中期板上的染色体排列[1-9]。有多少不同种类的染色质蛋白存在，以及它们如何合作形成一个可运动的染色质-微管界面尚不清楚。利用非洲爪蟾卵提取物重组的非着丝点染色质的新实验分析，我们证明了染色质上产生的微管运动是连续的和正端定向的。通过特异性抗体消耗，我们鉴定了两种不同的染色体驱动蛋白，激酶10 (Xkid)[8,10,11]和激酶4 (Xklp1)[12,13]，作为介导减数分裂染色质与微管相互作用的主要活性。有趣的是，我们发现，在染色质的接近生理环境和最小的体外实验中，较慢的运动，运动蛋白-10，更有效地招募微管，并在集体微管运输中占主导地位。我们的研究结果为运动蛋白介导的染色体臂运动的产生提供了分子活性的鉴定，并对两种主要染色体动蛋白的合作机制有了深入的了解。
During cell division, correct positioning of chromosomes in mitotic and meiotic spindles depends on interactions of microtubules with kinetochores and, especially in higher eukaryotes, with the chromosome arms [1, 2]. Chromokinesins, highly concentrated on mitotic and meiotic chromatin, are thought to actively push the chromosome arms toward the spindle center, thereby contributing to chromosome alignment at the metaphase plate in early mitosis [1-9]. How many distinct classes of chromokinesins exist and how they cooperate to form a motile chromatin-microtubule interface are not known. Using a novel experimental assay with nonkinetochore chromatin reconstituted from Xenopus egg extract, we demonstrate that the microtubule motility generated on chromatin is continuous and plus-end directed. Using specific antibody depletions, we identify two distinct chromokinesins, kinesin-10 (Xkid) [8, 10, 11] and kinesin-4 (Xklp1) [12, 13], as the major activities mediating the interaction of meiotic chromatin with microtubules. Interestingly, we find that the slower motor, kinesin-10, more efficiently recruits microtubules and also dominates in collective microtubule transport both in the close-to-physiological environment of chromatin and also in a minimal in vitro assay. Our results provide an identification of the molecular activities involved in the generation of motor protein-mediated chromosome arm motility and yield mechanistic insight into the cooperation of the two major chromokinesins.