Antagonistic spindle motors and MAPs regulate metaphase spindle length and chromosome segregation.
Antagonistic spindle motors and MAPs regulate metaphase spindle length and chromosome segregation.
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DOI：
10.1016/j.cub.2013.10.023
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发表时间：
2013-12-02
期刊：
影响因子：
--
通讯作者：
Tran PT
中科院分区：
文献类型：
--
作者：
Syrovatkina V;Fu C;Tran PT
中期描述了有丝分裂的一个阶段，其中染色体附着并定向在双极纺锤体上，以便随后在后期分离。在不同的细胞类型中，中期纺锤体保持特征性的恒定长度。中期纺锤体长度被认为是由不同的纺锤体微管（MT）及其与马达和MT相关蛋白（MAP）的相互作用所产生的推力和拉力的平衡来调节的。纺锤体长度被进一步提出是重要的染色体分离保真度，细胞短或长于正常中期纺锤体，通过删除或抑制个别有丝分裂马达或MAP，显示染色体分离缺陷。为了测试纺锤体长度控制的力平衡模型及其对染色体分离的影响，我们应用具有活细胞成像的快速微流体温度控制来监测在分裂酵母中期纺锤体中删除或关闭拮抗力贡献者的不同组合的效果。我们发现，纺锤体中间区蛋白驱动蛋白-5 cut 7 p和MT pallerase 1 p有助于向外的推力，和纺锤体动粒蛋白驱动蛋白-8 klp 5/6p和dam 1 p有助于向内的拉力。单独去除这些蛋白质会导致异常的中期纺锤体长度和染色体分离缺陷。在拮抗组合中去除这些蛋白质挽救了有缺陷的纺锤体长度，并且在一些组合中，还部分挽救了染色体分离缺陷。
Metaphase describes a phase of mitosis where chromosomes are attached and oriented on the bipolar spindle for subsequent segregation at anaphase. In diverse cell types, the metaphase spindle is maintained at characteristic constant length. Metaphase spindle length is proposed to be regulated by a balance of pushing and pulling forces generated by distinct sets of spindle microtubules (MTs) and their interactions with motors and MT-associated proteins (MAPs). Spindle length is further proposed to be important for chromosome segregation fidelity, as cells with shorter or longer than normal metaphase spindles, generated through deletion or inhibition of individual mitotic motors or MAPs, showed chromosome segregation defects. To test the force-balance model of spindle length control and its effect on chromosome segregation, we applied fast microfluidic temperature-control with live-cell imaging to monitor the effect of deleting or switching off different combinations of antagonistic force contributors in the fission yeast metaphase spindle. We show that spindle midzone proteins kinesin-5 cut7p and MT bundler ase1p contribute to outward pushing forces, and spindle kinetochore proteins kinesin-8 klp5/6p and dam1p contribute to inward pulling forces. Removing these proteins individually led to aberrant metaphase spindle length and chromosome segregation defects. Removing these proteins in antagonistic combination rescued the defective spindle length and, in some combinations, also partially rescued chromosome segregation defects.