Anaphase A: Disassembling Microtubules Move Chromosomes toward Spindle Poles.
Anaphase A: Disassembling Microtubules Move Chromosomes toward Spindle Poles.
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DOI：
10.3390/biology6010015
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发表时间：
2017-02-17
期刊：
影响因子：
4.2
通讯作者：
Asbury CL
中科院分区：
文献类型：
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作者：
Asbury CL
姐妹染色单体在后期的分离是有丝分裂的顶峰，也是细胞运动最引人注目的美丽例子之一。它由两个不同的过程组成：后期 A，通过缩短连接纤维，染色体向纺锤极移动；以及后期 B，通过纺锤体伸长，使两个极彼此分离。我在这里重点关注后期 A 染色体到极的运动。本章首先总结了染色体运动的经典观察，这些观察支持了当前对后期机制的理解。活细胞荧光显微镜研究表明，染色体向极的运动与连接染色体与极的着丝粒附着的微管纤维的分解有关。微管标记技术证实，着丝粒纤维解体通常是由于附着于着丝粒的正端的微管蛋白亚基丢失而发生的。此外，许多细胞中着丝粒纤维的分解部分是通过“通量”发生的，其中微管不断流向两极，微管蛋白亚基从负端丢失。讨论了如何维持承载附件以拆卸微管末端的分子机制模型，以及如何产生力来驱动这些拆卸耦合运动。
The separation of sister chromatids during anaphase is the culmination of mitosis and one of the most strikingly beautiful examples of cellular movement. It consists of two distinct processes: Anaphase A, the movement of chromosomes toward spindle poles via shortening of the connecting fibers, and anaphase B, separation of the two poles from one another via spindle elongation. I focus here on anaphase A chromosome-to-pole movement. The chapter begins by summarizing classical observations of chromosome movements, which support the current understanding of anaphase mechanisms. Live cell fluorescence microscopy studies showed that poleward chromosome movement is associated with disassembly of the kinetochore-attached microtubule fibers that link chromosomes to poles. Microtubule-marking techniques established that kinetochore-fiber disassembly often occurs through loss of tubulin subunits from the kinetochore-attached plus ends. In addition, kinetochore-fiber disassembly in many cells occurs partly through ‘flux’, where the microtubules flow continuously toward the poles and tubulin subunits are lost from minus ends. Molecular mechanistic models for how load-bearing attachments are maintained to disassembling microtubule ends, and how the forces are generated to drive these disassembly-coupled movements, are discussed.