CAREER: Asymmetry of microtubule dynamics in plant cytokinesis: the role of microtubule-nucleating protein MACET1

植物从海洋环境成功过渡到陆地环境的能力需要细胞活动的进化进步，包括细胞分裂的新机制。理解、预测和调节这种机制的能力可能会产生广泛的科学和经济影响。例如，维管形成层影响整个植物的生长，并通过异常大的前体细胞的分裂产生。已知这些分裂依赖于称为成膜体的植物特异性结构的扩展;然而，缺乏对成膜体扩展的详细了解。这个CAREER项目将使用实验室实验和数学建模的结合来填补这一知识空白，并将为增加细胞分裂速率和随后的木材产量提供基础知识，这些树木是为工业生物质而种植的。尽管在过去25年里，木材需求增长了36%，但林地面积继续缩小，发达国家严重依赖从热带地区进口木材。生长速度更快的生物工程树木有可能增加美国作为可再生材料的木材产量，并通过增加二氧化碳的封存带来额外的好处。这项研究的前沿概念将被整合到一个教育计划的学生参加区域美洲原住民高中和附近的刘易斯克拉克州立学院（ID）和瓦拉瓦拉社区学院（WA）。该计划将介绍植物作为自然资源的重要性;促进STEM教育;并鼓励STEM相关专业的职业生涯。成膜体的离心膨胀主要取决于微管的动态和不对称行为。PI已经鉴定了蛋白质MACET，其特异于胚状体，促进微管成核，在成膜体中表现出不对称定位，并促进成膜体扩张。这一发现为进一步研究成膜体不对称性的调节提供了一个令人兴奋的切入点。在本CAREER项目中，PI将使用遗传学、生物化学和细胞生物学方法的组合来表征胞质分裂中的MAET功能。此外，将使用定量活细胞成像和数学建模来确定MACET在成膜体中的不对称微管动力学中的作用。这些方法将促进我们对高度复杂但短暂的细胞内结构的基本规则的理解。由于生物体依赖于促进物质和能量不规则分布的机制来满足生物需求，因此理解成膜体不对称性将揭示生命支配原则的另一个方面。

The ability of plants to transition successfully from a marine to land environment required evolutionary advances in cellular activity, including a novel mechanism of cell division. The ability to understand, predict, and regulate this mechanism could have broad scientific and economic impacts. For example, the vascular cambium influences overall plant growth and is produced through the division of unusually large precursor cells. These divisions are known to rely on the expansion of a plant-specific structure termed the phragmoplast; however, a detailed understanding of phragmoplast expansion is lacking. This CAREER project will fill this knowledge gap using a combination of laboratory experiments and mathematical modeling and will provide foundational knowledge for increasing the rate of cell division, and subsequently wood yield, in trees that are grown for industrial biomass. Although the need for timber has grown by 36% over the past 25 years, forestland continues to shrink and developed countries depend heavily on imports from tropical zones. Bio-engineered trees with faster growth rates has the potential to increase production of timber as a renewable material in the US with additional benefits coming through increased sequestration of carbon dioxide. Cutting-edge concepts of this research will be integrated into an educational program for students that attend regional Native American high schools and nearby Lewis Clark State College (ID) and Walla Walla Community College (WA). The program will introduce the importance of plants as a natural resource; promote STEM education; and encourage careers in STEM-related professions. The expansion of the phragmoplast centrifugally is critically dependent on the dynamic and asymmetrical behavior of microtubules. The PI has identified the protein MACET, which is specific to embryophytes, promotes microtubule nucleation, exhibits asymmetrical localization in the phragmoplast, and facilitates phragmoplast expansion. This discovery provides an exciting entry point for further studies to unravel the regulation of phragmoplast asymmetry. In this CAREER project, the PI will use a combination of approaches in genetics, biochemistry, and cell biology to characterize MACET function(s) in cytokinesis. In addition, the role of MACET in asymmetrical microtubule dynamics in the phragmoplast will be determined using quantitative live cell imaging and mathematical modeling. These approaches will advance our understanding of the basic rules that govern the construction of highly complex, but transient intracellular structures. As organisms rely on mechanisms that facilitate the irregular distribution of matter and energy to meet biological needs, understanding phragmoplast asymmetry would unravel another facet of the governing principles of life.