University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, Ohnhorststrasse 18, D-22609 Hamburg, Germany.
University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, Ohnhorststrasse 18, D-22609 Hamburg, Germany.
Dev Cell. 2017 Oct 23;43(2):172-185.e5. doi: 10.1016/j.devcel.2017.09.017.
The spindle assembly checkpoint (SAC) in animals and yeast assures equal segregation of chromosomes during cell division. The prevalent occurrence of polyploidy in flowering plants together with the observation that many plants can be readily forced to double their genomes by application of microtubule drugs raises the question of whether plants have a proper SAC. Here, we provide a functional framework of the core SAC proteins in Arabidopsis. We reveal that Arabidopsis will delay mitosis in a SAC-dependent manner if the spindle is perturbed. However, we also show that the molecular architecture of the SAC is unique in plants. Moreover, the SAC is short-lived and cannot stay active for more than 2 hr, after which the cell cycle is reset. This resetting opens the possibility for genome duplications and raises the hypothesis that a rapid termination of a SAC-induced mitotic arrest provides an adaptive advantage for plants impacting plant genome evolution.
动物和酵母中的纺锤体装配检查点（SAC）可确保细胞分裂过程中染色体的均等分离。开花植物中多倍体的普遍存在，以及许多植物可以通过应用微管药物轻易地促使其基因组加倍的观察结果，提出了植物是否具有适当的 SAC 的问题。在这里，我们提供了拟南芥中核心 SAC 蛋白的功能框架。我们揭示，如果纺锤体受到干扰，拟南芥将以 SAC 依赖性方式延迟有丝分裂。然而，我们还表明，SAC 的分子结构在植物中是独特的。此外，SAC 的寿命很短，不能超过 2 小时保持活跃，之后细胞周期被重置。这种重置为基因组重复提供了可能性，并提出了一个假设，即 SAC 诱导的有丝分裂阻滞的快速终止为影响植物基因组进化的植物提供了适应性优势。
