Polarization of Plant Cell Division by Receptor-Like Proteins

极化（不对称）细胞分裂产生具有不同性质和命运的细胞，以及在植物和其他真核生物发育期间产生细胞多样性。然而，对植物细胞极化分裂的分子机制知之甚少。我们以前发现了一对受体样蛋白，PAN 1和PAN 2，它们共同作用于不对称分裂，在玉米叶表皮中产生气孔复合体的辅助细胞，调节叶片和周围空气之间的氧气，二氧化碳和水的交换。在这个项目中，我们将利用遗传学，显微镜，蛋白质组学和生物化学的工具建立在我们早期的研究结果的基础上，以推进我们对PAN受体如何促进辅助母细胞分裂的极化的理解。具体而言，我们将确定PAN 2蛋白在细胞中的作用，阐明PANs和其他已知的细胞极性调节因子之间的联系，分析PANs在分泌和/或内吞作用的空间调节中的作用，并确定PANs相互作用以促进分裂极性的其他蛋白质。本项目生成的数据将通过出版物和可通过http：//www.biology.ucsd.edu/labs/smith/访问的公开网站向公众提供;生物材料将由主要研究者保存，并根据要求分发。除了阐明植物发育的基本重要性过程外，该项目还将对科学教育产生积极影响。一名博士后研究员，两名研究生和多名本科生将通过参与本项目接受实习培训。此外，为期一周的植物基因组学实验室模块解决加州生命科学标准的7年级将实施每年的项目期间在两个中央圣地亚哥公立中学：格兰特和罗斯福。参与该模块将使这两所学校每年约350名7年级学生受益，其中大多数是罗斯福的少数民族学生，少数民族入学率为80%。

Polarized (asymmetric) cell divisions produce cells with different properties and fates, as well as generate cellular diversity during the development of plants and other eukaryotes. However, very little is known about molecular mechanisms underlying polarized cell division in plants. We previously discovered a pair of receptor-like proteins, PAN1 and PAN2, that work together to polarize the asymmetric divisions producing subsidiary cells of stomatal complexes in the maize leaf epidermis, which regulate the exchange of oxygen, carbon dioxide, and water between the leaf and surrounding air. In this project, we will build on our earlier findings using tools of genetics, microscopy, proteomics, and biochemistry to advance our understanding of how PAN receptors promote the polarization of subsidiary mother cell divisions. Specifically, we will determine where PAN2 protein acts in the cell, elucidate the connection between PANs and other known regulators of cell polarity, analyze the role of PANs in the spatial regulation of secretion and/or endocytosis, and identify other proteins that PANs interact with to promote division polarity. Data generated by this project will be made available to the public through publications and publicly accessible websites, accessible via http://www.biology.ucsd.edu/labs/smith/; biological materials will be maintained by the principal investigator and distributed upon request. In addition to elucidating processes of fundamental importance for plant development, this project will also positively impact science education. A postdoctoral fellow, two graduate students, and multiple undergraduates will receive interdisplinary training through participation in this project. In addition, a week-long plant genomics laboratory module addressing California Life Sciences Standards for 7th grade will be implemented each year of the project period in two central San Diego public middle schools: Grant and Roosevelt. Participation in the module will benefit about 350 7th graders per year at these two schools, most of whom are underrepresented minority students at Roosevelt, where the minority enrollment is 80%.