Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Cell. 2012 Apr 13;149(2):383-96. doi: 10.1016/j.cell.2012.02.051.
Despite their pivotal role in plant development, control mechanisms for oriented cell divisions have remained elusive. Here, we describe how a precisely regulated cell division orientation switch in an Arabidopsis stem cell is controlled by upstream patterning factors. We show that the stem cell regulatory PLETHORA transcription factors induce division plane reorientation by local activation of auxin signaling, culminating in enhanced expression of the microtubule-associated MAP65 proteins. MAP65 upregulation is sufficient to reorient the cortical microtubular array through a CLASP microtubule-cell cortex interaction mediator-dependent mechanism. CLASP differentially localizes to cell faces in a microtubule- and MAP65-dependent manner. Computational simulations clarify how precise 90° switches in cell division planes can follow self-organizing properties of the microtubule array in combination with biases in CLASP localization. Our work demonstrates how transcription factor-mediated processes regulate the cellular machinery to control orientation of formative cell divisions in plants.
尽管在植物发育中起着关键作用，但定向细胞分裂的控制机制仍然难以捉摸。在这里，我们描述了拟南芥干细胞中如何通过上游模式形成因子来精确调控细胞分裂方向的开关。我们表明，干细胞调节转录因子 PLETHORA 通过局部激活生长素信号诱导分裂平面重定向，最终导致微管相关 MAP65 蛋白的表达增强。MAP65 的上调足以通过 CLASP 微管-细胞皮层相互作用介体依赖性机制使皮层微管阵列重新定向。CLASP 以微管和 MAP65 依赖的方式在细胞面上差异定位。计算模拟阐明了如何通过微管阵列的自组织特性与 CLASP 定位的偏差相结合，精确地实现细胞分裂平面 90°的转换。我们的工作表明，转录因子介导的过程如何调节细胞机制来控制植物中形成性细胞分裂的方向。
