Micromanipulation of chromosomes reveals that cohesion release during cell division is gradual and does not require tension
Micromanipulation of chromosomes reveals that cohesion release during cell division is gradual and does not require tension
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DOI：
10.1016/j.cub.2004.11.052
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发表时间：
2004-12-14
期刊：
影响因子：
9.2
通讯作者：
Nicklas, RB
中科院分区：
文献类型：
--
作者：
Paliulis, LV;Nicklas, RB
在有丝分裂中，内聚力似乎沿着染色体的整个长度、着丝粒之间和沿着染色体臂存在。到了中期，姐妹染色单体表现为两个相邻但明显不同的杆体 [1-4]。姐妹染色单体在后期通过释放所有染色体内聚力而彼此分离。这与减数分裂 1 不同，减数分裂 1 中一对姐妹染色单体彼此分离，通过仅释放姐妹染色单体臂之间的内聚力移动到每个纺锤体极 [5-8]。然后，在后期 11，姐妹染色单体通过释放着丝粒内聚力而分离。我们的目标是找出有丝分裂和减数分裂中染色体上存在或不存在内聚力的位置以及它何时以及如何释放。我们通过用两个显微操作针拉动染色体来直接确定内聚力。因此，我们第一次可以区分显微镜下观察到的明显双重性和物理可分离性。我们发现，明显的双重性可能具有欺骗性：明显不同的姐妹染色单体通常无法分开。我们还证明了内聚力在后期逐渐释放，染色体看起来就像被拉开或拉开一样。这意味着需要来自纺锤体力的张力，但我们直接证明不需要张力即可将染色单体拉开。
In mitosis, cohesion appears to be present along the entire length of the chromosome, between centromeres and along chromosome arms. By metaphase, sister chromatids appear as two adjacent but visibly distinct rods [1-4]. Sister chromatids separate from one another in anaphase by releasing all chromosome cohesion. This is different from meiosis 1, in which pairs of sister chromatids separate from one another, moving to each spindle pole by releasing cohesion only between sister chromatid arms [5-8]. Then, in anaphase 11, sister chromatids separate by releasing centromere cohesion. Our objective was to find where cohesion is present or absent on chromosomes in mitosis and meiosis and when and how it is released. We determined cohesion directly by pulling on chromosomes with two micromanipulation needles. Thus, we could distinguish for the first time between apparent doubleness as seen in the microscope and physical separability. We found that apparent doubleness can be deceiving: Visibly distinct sister chromatids often cannot be separated. We also demonstrated that cohesion is released gradually in anaphase, with chromosomes looking as if they were unzipped or pulled apart. This implied that tension from spindle forces was required, but we showed directly that no tension was necessary to pull chromatids apart.