The chromokinesin, KLP3A, drives mitotic spindle pole separation during prometaphase and anaphase and facilitates chromatid motility
The chromokinesin, KLP3A, drives mitotic spindle pole separation during prometaphase and anaphase and facilitates chromatid motility
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DOI：
10.1091/mbc.e03-07-0489
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发表时间：
2004-01-01
影响因子：
3.3
通讯作者：
Scholey, JM
中科院分区：
文献类型：
--
作者：
Kwon, M;Morales-Mulia, S;Scholey, JM
有丝分裂需要多个基于微管（MT）的运动蛋白协同活动。在这里，我们研究了染色体驱动蛋白KLP3A对果蝇胚胎和培养的S2细胞有丝分裂纺锤体形态发生和染色体运动的贡献。通过免疫荧光，KLP3A与非纤维小点相关，这些小点集中在细胞核中，并与纺锤体显示mt依赖性关联。这些点集中在与染色体和中央纺锤体相关的模糊区域，并形成与末期中间体相关的明显带。胚胎中的抗体或显性负蛋白或S2细胞中的RNA干扰（RNAi）对KLP3A的功能破坏不会阻断有丝分裂，但会在有丝分裂纺锤体中产生缺陷。活胚胎有丝分裂的延时共聚焦观察表明，KLP3A抑制会破坏极性间mt的组织并产生短纺锤体。动力学分析表明，KLP3A在前期到中期转变（当它对抗Ncd时）和后期B期间有助于纺锤极分离，在后期A期间有助于染色单体运动的正常速率，并在末期有助于子核的适当间距。我们认为KLP3A作用于与染色体臂和中央纺锤体相关的mt，组织ipMT束，驱动纺锤杆分离，促进染色单体运动。
Mitosis requires the concerted activities of multiple microtubule (MT)-based motor proteins. Here we examined the contribution of the chromokinesin, KLP3A, to mitotic spindle morphogenesis and chromosome movements in Drosophila embryos and cultured S2 cells. By immunofluorescence, KLP3A associates with nonfibrous punctae that concentrate in nuclei and display MT-dependent associations with spindles. These punctae concentrate in indistinct domains associated with chromosomes and central spindles and form distinct bands associated with telophase midbodies. The functional disruption of KLP3A by antibodies or dominant negative proteins in embryos, or by RNA interference (RNAi) in S2 cells, does not block mitosis but produces defects in mitotic spindles. Time-lapse confocal observations of mitosis in living embryos reveal that KLP3A inhibition disrupts the organization of interpolar (ip) MTs and produces short spindles. Kinetic analysis suggests that KLP3A contributes to spindle pole separation during the prometaphase-to-metaphase transition (when it antagonizes Ncd) and anaphase B, to normal rates of chromatid motility during anaphase A, and to the proper spacing of daughter nuclei during telophase. We propose that KLP3A acts on MTs associated with chromosome arms and the central spindle to organize ipMT bundles, to drive spindle pole separation and to facilitate chromatid motility.