Microtubule Organization in Plant Cytokinesis

知识价值。植物细胞在细胞分裂过程中使用一种基于细胞骨架微管（MT）的称为片质体的装置来进行细胞质分裂。在膜质体中，mt向分裂位点聚合，并垂直于分裂面排列。囊泡沿着这些mt运输并融合形成新的细胞壁/细胞板。伴随着细胞板的组装，膜质体MT阵列向外向亲本膜扩展。虽然这个过程表面上被很好地描述了，但关于它是如何发生的机制细节却知之甚少。在本项目中，研究小组旨在了解在细胞分裂过程中，片质体mt是如何组装和重组的，并将以拟南芥为模型系统。这项工作的重点是揭示一个相互作用的蛋白质网络，作用于膜质体中间区，包括纺锤体检查点蛋白，MT交联剂和运动蛋白的参与。计划中的实验将结合高分辨率活细胞成像、生化蛋白质组学和突变分析。这里的新颖之处在于开发了一种范式转换模型，用于phragmoplast扩展，PI对此有坚实的初步数据支持。更广泛的影响。膜质体机制最早出现在高级绿藻中，被认为是与陆生植物发育相关的一个进化里程碑。其工作机制的细节被认为是理解植物进化的关键。除了与细胞生物学的学生分享细胞分裂的各种机制的知识外，PI还将积极招募本科生参与设计的实验。学生们不仅将接受生物化学、细胞生物学和遗传学方面的动手实验训练，他们还将通过实验研究、口头和书面报告他们的发现来建立竞争力。向当地高中生宣传植物生物学基础研究的重要性，激发他们对生物学的兴趣，鼓励他们寻求以科学为导向的职业。

Intellectual Merit. Plant cells employ a cytoskeletal microtubule (MT)-based apparatus called the phragmoplast to execute cytokinesis during cell division. In the phragmoplast, MTs polymerize toward the division site and are organized perpendicularly to the division plane. Vesicles are transported along these MTs and fuse to give rise to a new cell wall/plate. Concomitant with cell plate assembly, the phragmoplast MT array expands outward toward the parental membrane. Although this process is superficially well described, very little mechanistic detail is known on how it occurs. In this project, the research team aims to understand how phragmoplast MTs are assembled and reorganized during cytokinesis, and will use Arabidopsis thaliana as a model system. The work is focused on revealing an interactive protein network that acts in the phragmoplast midzone, including participation of spindle checkpoint proteins, MT crosslinkers, and kinesin motor proteins. Planned experiments will combine high-resolution live cell imaging, biochemical proteomics, and mutation analyses. Novelty here lies in development of a paradigm-shifting model for phragmoplast expansion, for which the PI has solid preliminary data support.Broader Impact. The phragmoplast mechanism first appeared in advanced green algae and is considered to be an evolutionary landmark associated with the development of land plants. Details of its working mechanism are considered critical to understand plant evolution. Besides sharing knowledge of diverse mechanisms of cytokinesis with cell biology students, the PI will actively recruit undergraduates to participate in the designed experiments. The students will not only receive hands-on laboratory training in biochemistry, cell biology, and genetics, they will also build competitiveness through bench research, and oral and written presentations of their discoveries. The importance of the basic plant biology research will be advocated to local high school students to spark their interest in biology and encourage them to seek science-oriented careers.