Goshima Gohta, Vale Ronald D
Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94107, USA.
J Cell Biol. 2003 Sep 15;162(6):1003-16. doi: 10.1083/jcb.200303022.
Kinesins and dyneins play important roles during cell division. Using RNA interference (RNAi) to deplete individual (or combinations of) motors followed by immunofluorescence and time-lapse microscopy, we have examined the mitotic functions of cytoplasmic dynein and all 25 kinesins in Drosophila S2 cells. We show that four kinesins are involved in bipolar spindle assembly, four kinesins are involved in metaphase chromosome alignment, dynein plays a role in the metaphase-to-anaphase transition, and one kinesin is needed for cytokinesis. Functional redundancy and alternative pathways for completing mitosis were observed for many single RNAi knockdowns, and failure to complete mitosis was observed for only three kinesins. As an example, inhibition of two microtubule-depolymerizing kinesins initially produced monopolar spindles with abnormally long microtubules, but cells eventually formed bipolar spindles by an acentrosomal pole-focusing mechanism. From our phenotypic data, we construct a model for the distinct roles of molecular motors during mitosis in a single metazoan cell type.
驱动蛋白和动力蛋白在细胞分裂过程中发挥着重要作用。利用RNA干扰（RNAi）技术去除单个（或多个组合的）马达蛋白，随后进行免疫荧光和延时显微镜观察，我们研究了果蝇S2细胞中胞质动力蛋白和所有25种驱动蛋白的有丝分裂功能。我们发现，有4种驱动蛋白参与双极纺锤体组装，4种驱动蛋白参与中期染色体排列，动力蛋白在中期到后期的转变中发挥作用，还有1种驱动蛋白参与胞质分裂。许多单个RNAi敲低实验观察到了功能冗余和完成有丝分裂的替代途径，只有3种驱动蛋白未能完成有丝分裂。例如，抑制两种微管解聚驱动蛋白最初会产生具有异常长微管的单极纺锤体，但细胞最终通过无中心体极聚焦机制形成双极纺锤体。根据我们的表型数据，我们构建了一个模型，用于描述后生动物单一细胞类型中有丝分裂过程中分子马达的不同作用。
