Molecular Genetic and Biochemical Analysis of the Fimbrin Gene Family From Arabidopsis

肌动蛋白细胞骨架对植物发育的核心重要性已经被广泛接受了一些年，然而，很少有详细的生化分析的各个组成部分，调节肌动蛋白为基础的功能已被执行。本项目通过在生物化学、细胞和遗传水平上表征拟南芥中的fimbrin-like肌动蛋白丝交联蛋白家族来解决这一缺陷。该项目的一个主要组成部分将利用反向遗传的方法，确定敲除突变体的五个fimplantation序列。这些基因敲除株系的表型分析将包括确定整株植物缺陷和通过使用免疫荧光和GFP技术检查不同细胞类型中肌动蛋白细胞骨架的详细结构。特定的肌动蛋白为基础的功能，如叶绿体方向，细胞质流，分裂平面的确定，对真菌病原体的反应，和细胞扩增将在敲除线进行分析。总的来说，这项研究将测试的假设，拟南芥中包含的fimmesium家族的成员具有不同的生化和细胞特性，因此，有可能有助于在单个植物细胞内的肌动蛋白为基础的功能的多样性。 此外，利用反向遗传学的力量，将直接测试这种多样化功能的潜力。所获得的结果将提供重要的洞察基本机制，支持细胞形态发生和细胞外刺激的反应。

The central importance of the actin cytoskeleton to plant development has been widely accepted for some years now; however, little detailed biochemical analysis of the individual components that regulate actin-based function has been performed. This project addresses this deficiency by characterizing at the biochemical, cellular and genetic levels, the family of fimbrin-like actin filament crosslinking proteins from Arabidopsis thaliana. A major component of this project will exploit reverse-genetic approaches by identifying knockout mutants for each of the five fimbrin sequences. Phenotypic analysis of these knockout lines will include determining whole plant defects and examining the detailed structure of the actin cytoskeleton in different cell types by using immunofluorescence and GFP technology. Specific actin-based functions such as chloroplast orientation, cytoplasmic streaming, determination of division planes, response to fungal pathogens, and cell expansion will be analyzed in the knockout lines. Collectively, this study will test the hypothesis that Arabidopsis contains members of the fimbrin family with distinct biochemical and cellular properties and which, therefore, have the potential to contribute to the diversity of actin-based function within individual plant cells. Furthermore, this potential for diverse functions will be tested directly by exploiting the power of reverse genetics. The results obtained will provide important insight into fundamental mechanisms that underpin cellular morphogenesis and responses to extracellular stimuli.