Molecular Analysis of a G Protein in Arabidopsis thaliana

G蛋白是存在于多种真核生物中的信号转导蛋白， 从人类到果蝇，从黏菌到 酵母;它们是异源三聚体（α，β和γ亚基） 在多种受体介导的 信号处理。 在植物中，细胞会对各种 激素和环境刺激;其中许多是已知的， 被认为与受体有关。 然而，G蛋白的功能 在植物信号转导过程中尚未得到证实。 该实验室最近分离出了一种基因（GPA 1）， 来自小型开花植物的G蛋白α亚基（G α 1）， 拟南芥 这是第一个被鉴定的G蛋白基因 在任何工厂。 这个实验室的长期目标是研究 植物中需要G蛋白的信号转导过程 功能，并比较和对比G蛋白功能之间 动物、植物和简单的真核生物。 当前的目标 提出的是表征GPA 1基因及其产物G α 1详细 GPA 1的时间和组织特异性模式 表达，G α 1的细胞内定位 蛋白质，和G α 1在植物中的功能将是 考察 将采取各种办法，包括 转录和翻译基因融合，转基因植物， 使用抗体的分析和突变分析。 已知G蛋白在动物中非常重要， 真核生物 它们是各种细胞所必需的， 信号过程，如激素刺激、光感受 由视网膜的细胞，黏菌的趋化性， 聚集和酵母交配反应。 有证据表明 一些植物信号转导过程也需要G蛋白， 尽管到目前为止，对植物中的这一点知之甚少。 该实验室最近表明，G蛋白存在于 通过克隆G蛋白亚基的基因获得植物。 理解 G蛋白在植物中的功能将是一个重要的 对我们细胞信号转导知识的贡献 植物的过程。

G proteins are signal transducers found in a variety of eukaryotic organisms, from humans to fruit flies, and from slime molds to yeasts; they are heterotrimers (of alpha, beta, and gamma subunits) that play crucial roles in many types of receptor-mediated signalling processes. In plants, cells respond to a variety of hormonal and environmental stimuli; many of these are known or thought to involve receptors. However, the function of G proteins in plant signal transduction processes has not been demonstrated. This laboratory has recently isolated a gene (GPA1) coding for a G protein alpha subunit (G alpha 1) from the small flowering plant, Arabidopsis thaliana. This is the first G protein gene identified in any plant. The long term goal of this laboratory is to study signal transduction processes in plants which require G protein functions, and to compare and contrast G protein functions between animals, plants and simple eukaryotes. The immediate objective proposed is to characterize the GPA1 gene and its product G alpha 1 in detail. The time and tissue specific patterns of GPA1 expression, the intracellular localization of the G alpha 1 protein, and the function of G alpha 1 in the plant will be examined. A wide range of approaches will be taken; they include transcriptional and translational gene fusions, transgenic plants, analysis using antibodies, and mutational analysis. G proteins are known to be very important in animals and simple eukaryotes. They are necessary for a variety of cellular signalling processes such as hormonal stimulation, photoreception by cells of the retina, chemotaxis of slime molds during aggregation, and the yeast mating response. There is evidence that some plant signal transduction processes also require G proteins, although, thus far, very little is known about this in plants. This laboratory has recently shown that G proteins are present in plants by cloning a gene for a G protein subunit. Understanding the functions of G proteins in plants will be an important contribution to our knowledge of cellular signal transduction processes in plants.