TPX2 levels modulate meiotic spindle size and architecture in Xenopus egg extracts.
TPX2 levels modulate meiotic spindle size and architecture in Xenopus egg extracts.
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DOI：
10.1083/jcb.201401014
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发表时间：
2014-08-04
期刊：
影响因子：
--
通讯作者：
Heald R
中科院分区：
文献类型：
--
作者：
Helmke KJ;Heald R
TPX 2水平通过Eg 5调节纺锤体结构，在促进纺锤体扩张的平铺的反平行阵列和将微管集中在纺锤体极点的交联的平行结构之间划分微管。纺锤体在分裂的真核细胞中分离染色体，并且其组装途径和形态在生物体和细胞类型中不同。我们研究了两种青蛙卵提取物中形成的减数分裂纺锤体之间差异的机制。小非洲爪蟾纺锤体抵制抑制两个重要因素的组装较大的非洲爪蟾纺锤体：RanGTP，其功能在染色质驱动的纺锤体组装，和驱动蛋白-5电机Eg 5，驱动反平行微管（MT）滑动。这表明MT相关蛋白TPX 2（非洲爪蟾驱动蛋白样蛋白2的靶向因子）的作用，其受Ran调节并结合Eg 5。事实上，TPX 2在X中的丰度是X的三倍。tropicalis提取物，并在X.光滑草提取物降低纺锤体长度和对Ran和Eg 5抑制的敏感性。较高的TPX 2水平招募Eg 5到极点，MT密度增加。我们建议，TPX 2水平调制主轴架构通过Eg 5，分区MT之间的平铺，反平行阵列，促进主轴扩张和交联，平行架构，集中在主轴极MT。
TPX2 levels modulate spindle architecture through Eg5, partitioning microtubules between a tiled, antiparallel array that promotes spindle expansion and a cross-linked, parallel architecture that concentrates microtubules at spindle poles. The spindle segregates chromosomes in dividing eukaryotic cells, and its assembly pathway and morphology vary across organisms and cell types. We investigated mechanisms underlying differences between meiotic spindles formed in egg extracts of two frog species. Small Xenopus tropicalis spindles resisted inhibition of two factors essential for assembly of the larger Xenopus laevis spindles: RanGTP, which functions in chromatin-driven spindle assembly, and the kinesin-5 motor Eg5, which drives antiparallel microtubule (MT) sliding. This suggested a role for the MT-associated protein TPX2 (targeting factor for Xenopus kinesin-like protein 2), which is regulated by Ran and binds Eg5. Indeed, TPX2 was threefold more abundant in X. tropicalis extracts, and elevated TPX2 levels in X. laevis extracts reduced spindle length and sensitivity to Ran and Eg5 inhibition. Higher TPX2 levels recruited Eg5 to the poles, where MT density increased. We propose that TPX2 levels modulate spindle architecture through Eg5, partitioning MTs between a tiled, antiparallel array that promotes spindle expansion and a cross-linked, parallel architecture that concentrates MTs at spindle poles.
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影响因子：
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影响因子：
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