CAREER: Mechanisms of division plane orientation in plant cells

这项研究试图了解调控植物细胞分裂的机制，植物细胞分裂最终产生地球上大部分的生物量。对细胞内分割位置的精确控制在整体构图和发育中起着至关重要的作用。尽管它很重要，但我们对多细胞生物体中的分裂平面是如何定位的知之甚少。植物是在多细胞环境中理解分裂平面方向的一个很好的模型，因为植物细胞不迁移，并且有明确定义的结构和蛋白质，明确地标记未来的分裂位置。这个项目将研究1)分裂部位定位的蛋白质和微管如何促进新细胞壁的正确定位，2)细胞分裂机械如何被引导到分裂部位，以及3)细胞分裂平面的位置是如何受到来自邻近细胞的局部机械或生化信号的调节。该项目将提供培训，促进美国在植物生物学方面的科学工作者，这是一个国家需要的领域。一名研究生、两名本科生、五名REU学生和一名博士后研究员将进行这项研究，同时获得在地方和国家会议上交流工作、指导他人、项目管理和伦理方面的经验。此外，480名生物学一年级学生将参加这项研究，以增强他们对基因组学和分子生物学方法的技术培训和理解。调查员继续培训和指导来自西班牙裔服务机构UCR的代表不足的第一代本科生和研究生。为了验证分裂部位定位的蛋白质调节微管动力学以定位形成细胞壁的假设，研究人员将使用体外微管蛋白相互作用分析和分裂部位的体内成像相结合的方法。除了评估目前已知的蛋白质在分裂部位的功能外，研究人员还使用正向遗传方法来鉴定在玉米胞质分裂和分裂平面定向方面存在缺陷的突变体。通过测序作图，她将确定这些突变体中的致病突变，并阐明它们与已知的分裂平面定向途径和蛋白质的相互作用。她推测，在拟南芥中，两条功能上冗余的通路参与了分裂平面的定位。她将使用敏化的突变背景来筛选导致分区平面定向缺陷的合成增强子突变。这将通过加州大学河滨分校(UCR)的生物实验室入门课程来进行。最后，她将使用数学建模和生物物理实验相结合的方法来确定改变植物分区平面位置的局部线索。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research seeks to understand the mechanisms regulating proliferative plant cell division, which eventually generates the majority of biomass on the planet. Precise control over the positioning of divisions within cells plays a critical role in overall patterning and development. Despite its fundamental importance, we know relatively little about how division planes are oriented in multicellular organisms. Plants are an excellent model to understand division plane orientation within multicellular contexts because plant cells do not migrate and have clearly defined structures and proteins that unambiguously label the future division site. This project will investigate 1) how division site-localized proteins and microtubules promote proper positioning of the new cell wall 2) how the cell division machinery is guided towards the division site, and 3) how the position of the cell division plane is modulated by local mechanical or biochemical cues from neighboring cells. This project will provide training that advances the U.S. scientific workforce in plant biology, an area of national need. One graduate student, two undergraduates, five REU students, and one postdoctoral researcher will perform this research while gaining experience in communicating their work at local and national conferences, mentoring others, project management, and ethics. In addition, 480 freshman biology students will participate in this research to enhance their technical training and understanding of genomics and molecular biology approaches. The investigator continue to train and mentor under-represented, first-generation undergraduate and graduate students from UCR, a Hispanic Serving Institution. To test the hypothesis that division site localized proteins modulate microtubule dynamics to position the forming cell wall, the investigator will use a combination of in vitro microtubule protein-interaction assays combined with in vivo imaging at the division site. In addition to assessing how currently known proteins function at the division site, the investigator has used a forward genetic approach to identify mutants with defects in cytokinesis and division plane orientation in maize. Using mapping-by-sequencing, she will identify the causative mutations in these mutants, and elucidate their interaction with known division plane orientation pathways and proteins. She hypothesizes that two functionally redundant pathways contribute to division plane positioning in Arabidopsis. She will use a sensitized mutant background to screen for synthetic enhancer mutations that cause defects in division plane orientation. This will be carried out by an introductory biology laboratory course at University of California, Riverside (UCR). Finally, she will use a combination of mathematical modeling and biophysical experiments to identify local cues that alter plant division plane positioning.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.