Biochemical and Structural Studies of Gamma-Tubulin in Arabidopsis Thaliana

拟南芥中γ-微管蛋白的生化和结构研究摘要微管阵列对植物细胞的分裂和形态发生是必不可少的，但这些阵列是如何组装和重排的在很大程度上是未知的。在动物和真菌细胞中，一种名为伽马微管蛋白的蛋白质对微管组装非常重要。在动物细胞中，γ-微管蛋白形成大的环状复合体，使微管组装成核，并保持附着在微管末端。在植物细胞中也存在伽马微管蛋白，但它如何与微管联系尚不清楚。环复合体尚未确定，伽马微管蛋白是否或如何控制微管组装也是未知的。这个项目的总体目标是阐明伽马微管蛋白在植物细胞中的功能。第一个具体目标是确定伽马-微管蛋白是否在拟南芥细胞中形成环复合体，如果它们确实形成了环复合体，则对它们进行纯化，并确定它们形成微管组装的能力。第二个具体目标是确定纯化的拟南芥伽马微管蛋白是否在体外结合在微管的末端或沿着微管的两侧。有证据表明，γ-微管蛋白在植物细胞内形成微管阵列的过程中起着重要的作用。如果γ-微管蛋白在植物细胞中的表现与在动物细胞中的不同，这些研究将为确定这种蛋白质在植物细胞中的实际功能提供一个很好的起点。

9808480OakleyBiochemical and Structural Studies of Gamma-Tubulin in ArabidopsisAbstractMicrotubule arrays are essential for cell division and morphogenesis in plant cells, but how these arrays assemble and rearrange is largely unknown. In animal and fungal cells a protein called gamma-tubulin is important for microtubule assembly. In animal cells gamma-tubulin forms large ring-shaped complexes that nucleate microtubule assembly and remain attached to the microtubule ends. In plant cells gamma-tubulin is also present, but how it associates with microtubules is unclear. Ring complexes have not yet been identified, and whether or how gamma-tubulin might control microtubule assembly is unknown. The overall goal of this project is to clarify the functions of gamma-tubulin in plant cells. The first specific goal is to determine if gamma-tubulin forms ring complexes in cells of Arabidopsis thaliana and if they do form, to purify them and determine their ability to nucleate microtubule assembly. The second specific goal is to determine whether purified Arabidopsis gamma-tubulin binds in vitro at the ends of microtubules or along their sides. Evidence for ring complexes and nucleation of assembly by gamma-tubulin will support an important role of gamma-tubulin in formation of microtubule arrays in plant cells in vivo. If gamma-tubulin behaves differently in plant cells than in animal cells, the studies will establish a good starting point to determine the actual functions of this protein in plant cells.