PRC1-labeled microtubule bundles and kinetochore pairs show one-to-one association in metaphase.
PRC1-labeled microtubule bundles and kinetochore pairs show one-to-one association in metaphase.
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DOI：
10.15252/embr.201642650
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发表时间：
2017-02
期刊：
影响因子：
7.7
通讯作者：
Tolić IM
中科院分区：
文献类型：
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作者：
Polak B;Risteski P;Lesjak S;Tolić IM
在有丝分裂纺锤体中，动粒微管形成k-纤维，而重叠或极间微管形成反平行阵列，其中包含胞质分裂的交联物蛋白调节因子1(Prc1)。我们最近发现，一种被称为桥接纤维的重叠束连接着最外层的姐妹k纤维。然而，重叠束和贯穿纺锤体的k纤维之间的关系仍不清楚。在这里，我们表明，在中期纺锤体中，超过90%的重叠束在姐妹k纤维之间起到了桥梁作用。我们发现，每个纺锤体的PRC1-GFP标记的束的数量几乎与动粒对的数量相同。活细胞成像显示，纺锤体赤道平面上的动粒运动与连接的Prc1-GFP标记纤维的运动高度相关，而与其他纤维的相关性随着距离的增加而减小。内源性PRC1的定位分析证实了用PrC1-GFP获得的结果。Prc1基因敲除减少了纺锤体中桥接纤维的厚度和动粒间距离，提示Prc1在中期纺锤体中起着桥接微管组织和力平衡的作用。
In the mitotic spindle, kinetochore microtubules form k‐fibers, whereas overlap or interpolar microtubules form antiparallel arrays containing the cross‐linker protein regulator of cytokinesis 1 (PRC1). We have recently shown that an overlap bundle, termed bridging fiber, links outermost sister k‐fibers. However, the relationship between overlap bundles and k‐fibers throughout the spindle remained unknown. Here, we show that in a metaphase spindle more than 90% of overlap bundles act as a bridge between sister k‐fibers. We found that the number of PRC1‐GFP‐labeled bundles per spindle is nearly the same as the number of kinetochore pairs. Live‐cell imaging revealed that kinetochore movement in the equatorial plane of the spindle is highly correlated with the movement of the coupled PRC1‐GFP‐labeled fiber, whereas the correlation with other fibers decreases with increasing distance. Analysis of endogenous PRC1 localization confirmed the results obtained with PRC1‐GFP. PRC1 knockdown reduced the bridging fiber thickness and interkinetochore distance throughout the spindle, suggesting a function of PRC1 in bridging microtubule organization and force balance in the metaphase spindle.