Molecular Characterization of the Ethylene Receptor ETRI from Arabidopsis

9513463 Bleecker是一种气体激素，乙烯调节高等植物的一些重要发育过程。参与乙烯感受的最初生化事件正在拟南芥植物中进行研究。植物中的ETR1基因编码一种与细菌感觉受体蛋白序列同源的蛋白质。ETR1基因的突变使人对乙烯不敏感。通过在酵母中表达ETR1基因，并发现转化的酵母将乙烯与ETR1蛋白结合，证实了ETR1编码的蛋白质作为乙烯受体的作用。利用酵母表达系统，改变形式的ETR1蛋白将被表达，以研究结合和信号转导的机制。利用体外诱变的方法，分析改变后的蛋白在转基因酵母中表达时与乙烯结合的能力，以及将乙烯信号转导到转基因植物中的效果。与其他来源资助的从酵母中纯化ETR1蛋白的工作相结合，拟议的研究将用于构建这种植物激素受体作用机制的分子模型。此外，这项研究中发现的ETR1基因的新突变形式将为生物技术人员提供在经济上重要的植物物种中通过基因工程改变乙烯敏感性的能力。***

9513463 Bleecker The gaseous hormone ethylene regulates a number of important developmental processes in higher plants. The initial biochemical events involved in ethylene perception are being investigated in the plant Arabidopsis thaliana. The ETR1 gene in the plant codes for a protein with sequence homology to sensory receptor proteins of bacteria. Mutations in the ETR1 gene confer dominant insensitivity to ethylene. The role of the protein coded by ETR1 as an ethylene receptor was confirmed by expressing the ETR1 gene in yeast and finding that the transformed yeast binds ethylene to the ETR1 protein. Using the yeast expression system, altered forms of the ETR1 protein will be expressed to investigate the mechanism of binding and signal transduction. Using in vitro mutagenesis, effects of specific changes in single amino acid residues of the protein will be followed by analysis of the ability of the altered protein to bind ethylene when expressed in transgenic yeast, and to transduce the ethylene signal transgenic plants. In conjunction with work funded by other sources on the purification of the ETR1 protein from yeast, the proposed research will be used to construct a molecular model for the mechanism of action of this plant hormone receptor. In addition the novel mutant forms of the ETR1 gene identified in this study will provide biotechnologists with the ability to genetically engineer alterations in ethylene sensitivity in economically important plant species. ***