Molecular mechanisms of cell polarity and development of distinct plasma membrane domains during formation of pollen apertures

为了发挥其功能，细胞通常需要在其表面形成不同于周围区域的蛋白质和脂质组成区域。这些区域被称为细胞结构域。细胞如何引导分子到特定位置并产生这样的结构域，人们知之甚少。花粉粒为细胞精确地在其表面形成区域的能力提供了一个美丽的例子。花粉表面通常被一层保护性结构——花粉壁外壁所覆盖。然而，在大多数植物中，花粉表面的某些区域不接受外壁的沉积，而是发育成特有的间隙，即孔。为了产生孔洞，发育中的花粉始终将未来的孔洞位置标记为不同于表面的其他位置，并保护它们免受外壁沉积。本项目将研究花粉形成孔结构域的分子机制。在这个项目的过程中，将培养几名青年科学家（一名博士后、研究生和本科生）。此外，花粉生物学将被用作一种工具，通过各种平台参与和教育公众，包括在当地科学博物馆、艺术课和植物园的活动。不同的细胞结构域的形成对细胞功能至关重要，但这些结构域的形成机制仍然知之甚少。花粉为研究这些机制提供了一个很好的模型。在大多数植物物种中，花粉粒的外细胞壁（称为外壁）不均匀地沉积在花粉表面，某些表面区域被排除在外壁沉积，并发育成特有的开口，即孔。孔的存在表明花粉发育过程中存在严格控制的机制来指定细胞结构域。本项目将研究近年来在拟南芥中发现的几种气孔基因的作用，以了解气孔形成的机制。通过各种遗传、成像、生化和计算方法，提出的工作将定义参与这一过程的细胞生物学和分子事件。本研究还将探讨与花粉孔多样性进化相关的问题，并将表征可能负责花粉孔形成过程中种间相似性和差异性的分子参与者。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

To perform their functions, cells often need to create regions on their surface which will differ from the surrounding areas in their protein and lipid composition. These regions are known as cellular domains. How cells direct molecules to specific positions and produce such domains is poorly understood. Pollen grains provide a beautiful example of a cells' ability to precisely form domains on their surfaces. Pollen surface is typically covered by a protective structure, pollen wall exine. However, in the majority of plants, certain regions on the pollen surface do not receive deposition of exine and instead develop into characteristic gaps, the apertures. To produce apertures, developing pollen consistently marks future aperture sites as different from the rest of the surface and protects them from exine deposition. This project will investigate molecular mechanisms through which pollen creates aperture domains. In the course of this project several young scientists (a postdoc as well as graduate and undergraduate students) will be trained. In addition, pollen biology will be used as a tool to engage and educate the general public through a variety of platforms, including activities at a local science museum, arts class, and a botanical garden.Formation of distinct cellular domains is critical for cell functions, but the mechanisms involved in creating these domains are still poorly understood. Pollen provides an excellent model for studying these mechanisms. In most plant species, the outer cell wall of pollen grains, called exine, is deposited on the pollen surface non-uniformly, with certain surface areas excluded from exine deposition and developing into characteristic openings, the apertures. Existence of apertures indicates the presence of tightly controlled mechanisms used by developing pollen to specify cellular domains. In this project, the roles of several aperture genes recently discovered in Arabidopsis will be studied to understand the mechanism of aperture formation. Through a variety of genetic, imaging, biochemical, and computational methods, the proposed work will define cell-biological and molecular events involved in this process. It will also explore the questions related to the evolution of pollen aperture diversity and will characterize molecular players that could be responsible for the interspecies similarities and differences in the process of aperture formation.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.