Kinesin-5-dependent Poleward Flux and Spindle Length Control in Drosophila Embryo Mitosis
Kinesin-5-dependent Poleward Flux and Spindle Length Control in Drosophila Embryo Mitosis
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DOI：
10.1091/mbc.e08-10-1033
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发表时间：
2009-03-15
影响因子：
3.3
通讯作者：
Scholey, Jonathan M.
中科院分区：
文献类型：
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作者：
Brust-Mascher, Ingrid;Sommi, Patrizia;Scholey, Jonathan M.
我们使用抗体显微注射和遗传操作分析了同四聚体动力蛋白-5 KLP61F在恒星状、中心体控制的果蝇胚胎纺锤体中的各种作用，并验证了它能使极性微管（MT）分离，从而控制极性通量和纺锤体长度的假设。在野生型和Ncd零突变体胚胎中，抗KLP61F将马达与纺锤体分离，使不同纺锤体的KLP61F含量呈现空间梯度，这在KLP61F- gfp转基因胚胎中可见。基因剂量实验和活klp61f突变体的延时显微镜支持了由此产生的有丝分裂缺陷，结果表明，在NEB后，klp61f驱动持续的MT捆绑和反平行MT向外滑动，从而促进了几个对皮质破坏不敏感的过程。KLP61F活性对ipMTs和着丝点MTs的极向通量以及中期纺锤体的长度都有贡献。KLP61F活性通过拮抗Ncd和另一个未知的力发生器来维持前期纺锤体，并驱动后期B，尽管纺锤体伸长的速度对马达的浓度相对不敏感。最后，KLP61F活性有助于正常的染色体聚集、着丝点间距和后期A率。因此，klp61f驱动的滑动丝机制有助于该系统中有丝分裂的多个方面。
We used antibody microinjection and genetic manipulations to dissect the various roles of the homotetrameric kinesin-5, KLP61F, in astral, centrosome-controlled Drosophila embryo spindles and to test the hypothesis that it slides apart interpolar (ip) microtubules (MT), thereby controlling poleward flux and spindle length. In wild-type and Ncd null mutant embryos, anti-KLP61F dissociated the motor from spindles, producing a spatial gradient in the KLP61F content of different spindles, which was visible in KLP61F-GFP transgenic embryos. The resulting mitotic defects, supported by gene dosage experiments and time-lapse microscopy of living klp61f mutants, reveal that, after NEB, KLP61F drives persistent MT bundling and the outward sliding of antiparallel MTs, thereby contributing to several processes that all appear insensitive to cortical disruption. KLP61F activity contributes to the poleward flux of both ipMTs and kinetochore MTs and to the length of the metaphase spindle. KLP61F activity maintains the prometaphase spindle by antagonizing Ncd and another unknown force-generator and drives anaphase B, although the rate of spindle elongation is relatively insensitive to the motor's concentration. Finally, KLP61F activity contributes to normal chromosome congression, kinetochore spacing, and anaphase A rates. Thus, a KLP61F-driven sliding filament mechanism contributes to multiple aspects of mitosis in this system.