Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Plant Cell Physiol. 2013 Mar;54(3):333-42. doi: 10.1093/pcp/pcs175. Epub 2012 Dec 17.
Formative cell divisions utilizing precise rotations of cell division planes generate and spatially place asymmetric daughters to produce different cell layers. Therefore, by shaping tissues and organs, formative cell divisions dictate multicellular morphogenesis. In animal formative cell divisions, the orientation of the mitotic spindle and cell division planes relies on intrinsic and extrinsic cortical polarity cues. Plants lack known key players from animals, and cell division planes are determined prior to the mitotic spindle stage. Therefore, it appears that plants have evolved specialized mechanisms to execute formative cell divisions. Despite their profound influence on plant architecture, molecular players and cellular mechanisms regulating formative divisions in plants are not well understood. This is because formative cell divisions in plants have been difficult to track owing to their submerged positions and imprecise timings of occurrence. However, by identifying a spatiotemporally inducible cell division plane switch system applicable for advanced microscopy techniques, recent studies have begun to uncover molecular modules and mechanisms for formative cell divisions. The identified molecular modules comprise developmentally triggered transcriptional cascades feeding onto microtubule regulators that now allow dissection of the hierarchy of the events at better spatiotemporal resolutions. Here, we survey the current advances in understanding of formative cell divisions in plants in the context of embryogenesis, stem cell functionality and post-embryonic organ formation.
有丝分裂通过精确旋转细胞分裂面进行，从而产生和空间定位非对称的子细胞，以产生不同的细胞层。因此，通过塑造组织和器官，有丝分裂决定了多细胞形态发生。在动物的有丝分裂中，有丝分裂纺锤体和细胞分裂面的取向依赖于内在和外在的皮质极性线索。植物缺乏动物中已知的关键因子，并且细胞分裂面在有丝分裂纺锤体阶段之前确定。因此，植物似乎已经进化出了专门的机制来执行有丝分裂。尽管它们对植物结构有深远的影响，但调节植物有丝分裂的分子参与者和细胞机制还没有被很好地理解。这是因为植物的有丝分裂难以追踪，因为它们处于水下位置，并且发生的时间不准确。然而，通过鉴定一种适用于先进显微镜技术的时空诱导的细胞分裂面转换系统，最近的研究开始揭示有丝分裂的分子模块和机制。已鉴定的分子模块包括发育触发的转录级联反应，这些反应反馈到微管调节剂上，现在可以在更好的时空分辨率下解析事件的层次结构。在这里，我们调查了在胚胎发生、干细胞功能和胚胎后器官形成背景下，植物有丝分裂的最新理解进展。
