Department of Genetics, University of Cambridge, Cambridge, UK.
Cell Cycle. 2013 Aug 15;12(16):2643-55. doi: 10.4161/cc.25671. Epub 2013 Jul 16.
Spindle orientation defines the plane of cell division and, thereby, the spatial position of all daughter cells. Here, we develop a live cell microscopy-based methodology to extract spindle movements in human epithelial cell lines and study how spindles are brought to a pre-defined orientation. We show that spindles undergo two distinct regimes of movements. Spindles are first actively rotated toward the cells' long-axis and then maintained along this pre-defined axis. By quantifying spindle movements in cells depleted of LGN, we show that the first regime of rotational movements requires LGN that recruits cortical dynein. In contrast, the second regime of movements that maintains spindle orientation does not require LGN, but is sensitive to 2ME2 that suppresses microtubule dynamics. Our study sheds first insight into spatially defined spindle movement regimes in human cells, and supports the presence of LGN and dynein independent cortical anchors for astral microtubules.
纺锤体的取向决定了细胞分裂的平面，从而决定了所有子细胞的空间位置。在这里，我们开发了一种基于活细胞显微镜的方法来提取人上皮细胞系中的纺锤体运动，并研究如何将纺锤体引导到一个预先确定的方向。我们发现纺锤体经历了两种不同的运动状态。纺锤体首先被主动旋转到细胞的长轴上，然后沿着这个预先确定的轴保持。通过在 LGN 缺失的细胞中定量测量纺锤体的运动，我们表明第一阶段的旋转运动需要募集皮层动力蛋白的 LGN。相比之下，维持纺锤体取向的第二阶段运动不需要 LGN，但对抑制微管动力学的 2ME2 敏感。我们的研究首次揭示了人类细胞中空间定义的纺锤体运动状态，并支持了星体微管存在 LGN 和动力蛋白独立的皮层锚定。
