GLUCOSE SIGNAL TRANSDUCTION PATHWAY IN PLANTS

植物中的葡萄糖信号转导途径

• 批准号: 6387060
• 负责人: JEN SHEEN
• 金额: $ 27.68万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6387060
• 关键词: Arabidopsis; biological signal transduction; gene mutation; genetically modified plants; glucose; glucose metabolism; phosphorylation; plant genetics

The long-term objective of this research proposal is to elucidate the molecular mechanisms underlying the glucose signal transduction pathway in plants using Arabidopsis thaliana as a model system. Sugar production through photosynthesis is the most important activity in plants and supports all life on the planet. Recent studies from my laboratory have provided compelling evidence to support the new concept that sugars are acting as central signaling molecules to modulate photosynthetic gene expression and coordinate many vital processes, including germination, seedling development, leaf and root differentiation, flowering, and senescence in plants. By using mutants, transient expression, and transgenic plants, we have provided new evidence that glucose signaling can be uncoupled from glucose metabolism, and at least one specific hexokinase (AtHXK1) has dual catalytic and regulatory roles as a major glucose sensor/signal transducer in plants. The proposed studies employing a plant model A.thaliana will reveal unconventional and exciting new insights into the molecular mechanisms of glucose sensing and signaling in plants with potential implications in other eukaryotes. A combination of molecular, biochemical, genetic, and cellular approaches will be used. Three specific aims are: 1) Define the glucose responses mediated through AtHXK1 as a sensor/signal transducer An Arabidopsis AtHXK1 knockout mutant and transgenic plants with altered HXK levels will be used to identify HXK- mediated glucose-responsive target genes. A comprehensive sets of glucose-dependent bioassays will be tested to define HXK- mediated developmental activities. Glucose phosphorylation and accumulation will be monitored. These experiments will establish the standards for analyzing sugar responses in plants and will unequivocally define the role of specific HXK as a glucose sensor/signal transducer by genetic means. 2) Elucidate the molecular mechanism of AtHXK1 function in glucose sensing and signaling Comprehensive experiments are proposed to determine the expression patterns and subcellular localization of AtHXK1, establish AtHXK1 functional assays, generate and analyze AtHXK1 mutants, characterize the AtHXK1 protein complex, and identify AtHXK1 signaling partners. 3) Identify the components in the glucose signal transduction pathways The Arabidopsis mutants that are glucose insensitive (gin) will be phenotypically and molecularly characterized. The gene for the most interesting mutant gin1 will be isolated and analyzed.

该研究计划的长期目标是以拟南芥为模型系统，阐明植物中葡萄糖信号转导途径的分子机制。 通过光合作用生产糖是植物最重要的活动，支持地球上的所有生命。 我实验室最近的研究提供了令人信服的证据来支持新概念，即糖作为中央信号分子来调节光合作用基因表达并协调许多重要过程，包括植物的发芽、幼苗发育、叶和根分化、开花和衰老。 通过使用突变体、瞬时表达和转基因植物，我们提供了新的证据，表明葡萄糖信号传导可以与葡萄糖代谢分离，并且至少一种特定的己糖激酶（AtHXK1）作为主要的葡萄糖传感器/信号转导器具有双重催化和调节作用。植物。 拟定的研究采用拟南芥植物模型，将揭示植物中葡萄糖传感和信号转导分子机制的非常规且令人兴奋的新见解，并对其他真核生物具有潜在影响。 将结合使用分子、生物化学、遗传和细胞方法。 三个具体目标是： 1) 定义通过 AtHXK1 作为传感器/信号转换器介导的葡萄糖反应拟南芥 AtHXK1 敲除突变体和具有改变的 HXK 水平的转基因植物将用于鉴定 HXK 介导的葡萄糖反应靶基因。 将测试一套全面的葡萄糖依赖性生物测定法，以确定 HXK 介导的发育活动。 将监测葡萄糖磷酸化和积累。 这些实验将建立分析植物糖反应的标准，并将通过遗传手段明确定义特定 HXK 作为葡萄糖传感器/信号转换器的作用。 2) 阐明AtHXK1在葡萄糖传感和信号传导中功能的分子机制提出综合实验来确定AtHXK1的表达模式和亚细胞定位，建立AtHXK1功能测定，生成和分析AtHXK1突变体，表征AtHXK1蛋白复合物，并鉴定AtHXK1信号传导合作伙伴。 3) 鉴定葡萄糖信号转导途径中的成分将对葡萄糖不敏感的拟南芥突变体（杜松子酒）进行表型和分子表征。 最有趣的突变体 gin1 的基因将被分离和分析。