The motor for poleward chromosome movement in anaphase is in or near the kinetochore.
The motor for poleward chromosome movement in anaphase is in or near the kinetochore.
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DOI：
10.1083/jcb.109.5.2245
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发表时间：
1989-11
期刊：
影响因子：
--
通讯作者：
Nicklas RB
中科院分区：
文献类型：
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作者：
Nicklas RB
我已经检验了关于后期染色体到极点运动的两种相互矛盾的观点。染色体可能被由着丝点微管和相关马达组成的牵引纤维拉向两极，或者它们可能由着丝点内的马达推动自己。我切断了位于染色体和一极之间的去膜蚱蜢精母细胞的纺锤体，把极区扫掉，去掉了一部分可能的牵引纤维。染色体继续运动，在最好的例子中，染色体移动到距离切割边缘1微米的范围内。在边缘之外没有任何东西来支持运动，而来自后面的推力是不太可能的，因为在分裂的染色体后面的区域间的切割并没有阻止运动。因此，我得出结论，马达一定在着丝点内或离着丝点1微米以内。不那么确凿的证据表明着丝点本身是马达。另一种方法是外部马达拉着着丝点微管或直接拉着着丝点。牵引马达会使着丝点微管随染色体移动，因此在切割的半纺锤体中，当染色体向着丝点移动时，微管会从切割边缘伸出。没有看到突出的东西；然而，微管在挤压过程中解聚的可能性虽然不大，但也不能排除。可以肯定的是，后期染色体向极运动的马达一定在着丝点或离着丝点很近。
I have tested two contending views of chromosome-to-pole movement in anaphase. Chromosomes might be pulled poleward by a traction fiber consisting of the kinetochore microtubules and associated motors, or they might propel themselves by a motor in the kinetochore. I cut through the spindle of demembranated grasshopper spermatocytes between the chromosomes and one pole and swept the polar region away, removing a portion of the would-be traction fiber. Chromosome movement continued, and in the best examples, chromosomes moved to within 1 micron of the cut edge. There is nothing beyond the edge to support movement, and a push from the rear is unlikely because cuts in the interzone behind the separating chromosomes did not stop movement. Therefore, I conclude that the motor must be in the kinetochore or within 1 micron of it. Less conclusive evidence points to the kinetochore itself as the motor. The alternative is an external motor pulling on the kinetochore microtubules or directly on the kinetochore. A pulling motor would move kinetochore microtubules along with the chromosome, so that in a cut half-spindle, the microtubules should protrude from the cut edge as chromosomes move toward it. No protrusion was seen; however, the possibility that microtubules depolymerize as they are extruded, though unlikely, is not ruled out. What is certain is that the motor for poleward chromosome movement in anaphase must be in the kinetochore or very close to it.