Mitotic spindle assembly by two different pathways in vitro
Mitotic spindle assembly by two different pathways in vitro
复制标题
体外有丝分裂纺锤体通过两种不同途径组装
DOI：
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发表时间：
1991
影响因子：
7.8
通讯作者：
T. Mitchison
中科院分区：
文献类型：
--
作者：
K. Sawin;T. Mitchison
我们使用非洲爪哇的卵子提取物来研究无细胞系统中纺锤体的形态发生，并使用荧光模拟细胞化学的方法在体外鉴定了纺锤体组装的两条途径。当去膜的精子核被加入到停止在有丝分裂状态的卵子提取液中时，单个核指导极化的微管阵列的组装，我们称之为半纺锤体；然后半纺锤体成对融合形成双极纺锤体。相反，当精子核加入被诱导进入间期并在随后的有丝分裂中停止的提取物中时，单个精子核可以指导完整纺锤体的组装。我们发现体外的微管阵列强烈偏向染色质，但这并不依赖于特定的动粒-微管相互作用。事实上，尽管我们已经在体外组装的纺锤体中确定了形态上的和可能具有功能的动点，但动点似乎并不在两种组装途径中建立稳定的、双极微管阵列方面发挥必要的作用。这两条途径的特点表明，纺锤体组装涉及一系列选择性微管稳定，包括染色质-微管相互作用和反平行微管-微管相互作用，基本的分子相互作用在两条途径中可能是相同的。这一体外重建系统对于识别调控不对称微管阵列生成的分子以及了解纺锤体的形态发生都是有用的。
We have used Xenopus egg extracts to study spindle morphogenesis in a cell-free system and have identified two pathways of spindle assembly in vitro using methods of fluorescent analogue cytochemistry. When demembranated sperm nuclei are added to egg extracts arrested in a mitotic state, individual nuclei direct the assembly of polarized microtubule arrays, which we term half-spindles; half-spindles then fuse pairwise to form bipolar spindles. In contrast, when sperm nuclei are added to extracts that are induced to enter interphase and arrested in the following mitosis, a single sperm nucleus can direct the assembly of a complete spindle. We find that microtubule arrays in vitro are strongly biased towards chromatin, but this does not depend on specific kinetochore-microtubule interactions. Indeed, although we have identified morphological and probably functional kinetochores in spindles assembled in vitro, kinetochores appear not to play an obligate role in the establishment of stable, bipolar microtubule arrays in either assembly pathway. Features of the two pathways suggest that spindle assembly involves a hierarchy of selective microtubule stabilization, involving both chromatin-microtubule interactions and antiparallel microtubule-microtubule interactions, and that fundamental molecular interactions are probably the same in both pathways. This in vitro reconstitution system should be useful for identifying the molecules regulating the generation of asymmetric microtubule arrays and for understanding spindle morphogenesis in general.
DOI：
10.1073/pnas.85.9.3009
发表时间：
1988-05-01
影响因子：
11.1
作者：
LOHKA, MJ;HAYES, MK;MALLER, JL
通讯作者：
MALLER, JL