论文题目：The kinesin motor POS3 and the microtubule polymerase MOR1 coordinate chromosome congression during mitosis in Arabidopsis
论文作者：Yu Chen, Haofeng Liu, Yuanfeng Li, Xiao Shen, Shuting Li, Lan Yang, Xue An, Pei Lei, Xiaomin Wang, Hongchang Zhang,Jen Sheen, Fei Yu, Xiayan Liu
论文摘要：
Faithful chromosome segregation during mitosis is crucial for eukaryotic organisms. Centromere-associated protein E (CENP-E), a kinetochore-localized kinesin motor, facilitates chromosome congression during mitosis in animals. However, it remains unclear whether plants rely on kinesins similar to CENP-E for chromosome alignment. In our genetic screens for Arabidopsis ( Arabidopsis thaliana ) mutants that are hypersensitive to the microtubule-destabilizing drug propyzamide, we identified propyzamide oversensitive3-1 ( pos3-1 ), which harbors a mutation in a kinesin-like protein that shares sequence similarity with the N-terminal region of CENP-E. We demonstrated that POS3 dynamically associates with kinetochores during chromosome congression and segregation in mitosis. Moreover, loss of POS3 results in prolonged mitosis, increased aneuploidy, and misaligned chromosomes near the spindle poles. Unexpectedly, we discovered a direct physical interaction and functional link between POS3 and the microtubule polymerase MICROTUBULE ORGANIZATION1 (MOR1) in regulating chromosome alignment and segregation during mitosis. Finally, we showed that MOR1 is required for the kinetochore localization of POS3 in mitosis. Together, our findings establish the vital role of POS3 in chromosome congression and uncover a functional link between POS3 and MOR1 that is essential for proper chromosome alignment and segregation in plant mitosis.
有丝分裂中染色体的均等分离对真核生物至关重要。在动物细胞中，定位于动粒的驱动蛋白CENP-E促进有丝分裂期间染色体的会聚，然而植物是否依赖类似CENP-E的驱动蛋白来实现染色体的会聚目前尚不清楚。在拟南芥微管解聚药物propyzamide超敏感突变体筛选中鉴定得到的 propyzamide oversensitive3-1 （ pos3-1 ）突变体中,与CENP-E具有序列相似性的驱动蛋白POS3发生突变。有丝分裂中，POS3在染色体会聚和分离过程中动态地定位于动粒。POS3功能缺失导致有丝分裂期持续时间增长、非整倍体细胞增多以及染色体滞留在两极无法在赤道板列队等有丝分裂缺陷。出乎意料的是，发现POS3与微管聚合酶MICROTUBULE ORGANIZATION1（MOR1）在染色体会聚和分离的调控中存在直接的物理互作和功能互作。MOR1促进POS3在有丝分裂中定位于动粒。综上所述，这些研究结果确立了POS3在有丝分裂中调控染色体会聚的关键作用，揭示了POS3-MOR1功能单元调控染色体会聚和分离的分子机制。
原文链接：https://doi.org/10.1093/plcell/koaf053