The kinesin ATK5 functions in early spindle assembly in Arabidopsis
The kinesin ATK5 functions in early spindle assembly in Arabidopsis
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DOI：
10.1105/tpc.106.047613
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发表时间：
2007-01-01
期刊：
影响因子：
11.6
通讯作者：
Cyr, Richard
中科院分区：
文献类型：
--
作者：
Ambrose, J. Christian;Cyr, Richard
在细胞分裂过程中，有丝分裂纺锤体将染色体分裂成子核。在高等植物中，控制纺锤体组装和功能的分子机制在很大程度上仍未被探索。在这里，缺乏激酶-14 （ATK5）的拟南芥植物有丝分裂的活细胞成像揭示了早期纺锤体形成过程中的缺陷。atk5-1植物的纺锤体从前期开始，一直持续到前期中期后期，纺锤体在前期变得异常细长，经常弯曲，并具有分叉的杆。atk5-1细胞前期和中期纺锤体伸长时间延长。黄色荧光蛋白的延时成像：ATK5显示在核膜破裂之前与核周微管共定位，之后它从两极向内移动到中间区域，在反平行微管之间的重叠区域逐渐富集。体外微管运动分析表明，在ATK5的存在下，两个微管以一定角度相遇，可以相互作用和对齐，形成一个线性束。这些数据表明，ATK5参与了反平行极性间微管的搜索和捕获，在那里它有助于产生对齐微管的力，从而影响纺锤体的长度、宽度和完整性。
During cell division, the mitotic spindle partitions chromosomes into daughter nuclei. In higher plants, the molecular mechanisms governing spindle assembly and function remain largely unexplored. Here, live cell imaging of mitosis in Arabidopsis thaliana plants lacking a kinesin-14 (ATK5) reveals defects during early spindle formation. Beginning during prophase and lasting until late prometaphase, spindles of atk5-1 plants become abnormally elongated, are frequently bent, and have splayed poles by prometaphase. The period of spindle elongation during prophase and prometaphase is prolonged in atk5-1 cells. Time-lapse imaging of yellow fluorescent protein: ATK5 reveals colocalization with perinuclear microtubules before nuclear envelope breakdown, after which it congresses inward from the poles to the midzone, where it becomes progressively enriched at regions of overlap between antiparallel microtubules. In vitro microtubule motility assays demonstrate that in the presence of ATK5, two microtubules encountering one another at an angle can interact and coalign, forming a linear bundle. These data indicate that ATK5 participates in the search and capture of antiparallel interpolar microtubules, where it aids in generating force to coalign microtubules, thereby affecting spindle length, width, and integrity.