Inositol Synthesis and Catabolism in Plants

植物中肌醇的合成和分解代谢

• 批准号: 0316705
• 负责人: Glenda Gillaspy
• 金额: $ 40.01万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0316705&HistoricalAwards=false
• 关键词: Inositol; Synthesis; Catabolism; Plants

This project utilizes molecular, genetic and biochemical tools to address a fundamental pathway present in most organisms that gives rise to a large number of required metabolites. Myo-inositol synthesis and catabolism is crucial in many multiceullar eukaryotes for production of phosphatidylinositol signaling molecules, glycerophosphoinositide membrane anchors, cell wall pectic non-cellulosic polysaccharides, Vitamin C, and several other molecules. Myo-inositol synthesis and catabolism are especially important in plants and ground-breaking biochemical experiments from the 1960's and 70's defined all of the major enzymes involved. Multigene families encoding myo-inositol monophosphatase (IMP; EC 3.1.3.25), and myo-inositol oxygenase (MIOX; E.C. 1.13.99.1) enzymes are present in the plant model system, Arabidopsis thaliana. The project will address the hypothesis that the IMP and MIOX genes have specialized roles in providing inositol for various pathways. To test this hypothesis, IMP and MIOX expression patterns will be examined. To address whether the different IMP and MIOX isoforms have different catalytic activities, recombinant proteins will be produced and their substrate specificities determined. Complementing this approach will be a genetic analysis which is crucial for determining function in vivo. Metabolic profiling by gas chromatography-mass spectrometry will be utilized to determine the effect of each isoform on levels of the myo-inositol, phosphatidylinositol, D-glucuronic acid, galactinol, ascorbic acid, and other inositol metabolites as required. The inositol synthesis and catabolism pathway provides inositol for many required cellular functions of both plants and animals. This project will investigate how a model plant controls the synthesis of inositol to meet its varying needs. Since the dynamics of inositol turnover in plants can impact the environment through phosphorous contamination of soil, this research will provide knowledge about possible ways to limit such contamination. As well, inositol synthesis is altered in diseases such as diabetes, Down's syndrome, Alzheimer's and bipolar disorder. Thus investigating the basic science of inositol metabolism is vital also for understanding the pathology of these diseases.

该项目利用分子、遗传和生物化学工具来解决大多数生物体中存在的产生大量所需代谢物的基本途径。 肌醇合成和催化在许多多细胞真核生物中对于产生磷脂酰肌醇信号传导分子、甘油磷酸肌醇膜锚、细胞壁果胶非纤维素多糖、维生素C和几种其他分子是至关重要的。 肌醇的合成和催化在植物中特别重要，20世纪60年代和70年代的突破性生物化学实验定义了所有涉及的主要酶。 编码肌醇单磷酸酶（IMP; EC 3.1.3.25）和肌醇加氧酶（MIOX; E.C. 1.13.99.1）酶存在于植物模型系统拟南芥中。 该项目将解决IMP和MIOX基因在为各种途径提供肌醇方面具有专门作用的假设。 为了检验这一假设，将检查IMP和MIOX表达模式。 为了确定不同的IMP和MIOX亚型是否具有不同的催化活性，将生产重组蛋白并测定其底物特异性。 补充这一方法将是一个遗传分析，这是至关重要的确定功能在体内。 根据需要，将采用气相色谱-质谱法进行代谢分析，以确定每种亚型对肌醇、磷脂酰肌醇、D-葡萄糖醛酸、半乳糖苷醇、抗坏血酸和其他肌醇代谢物水平的影响。 肌醇合成和催化途径为植物和动物的许多所需细胞功能提供肌醇。 本计画将探讨模式植物如何控制肌醇的合成以满足其不同的需求。 由于植物中肌醇周转的动态可以通过土壤的磷污染来影响环境，因此这项研究将提供有关限制这种污染的可能方法的知识。 同样，肌醇的合成在糖尿病、唐氏综合症、阿尔茨海默氏症和双相情感障碍等疾病中也会改变。 因此，研究肌醇代谢的基础科学对于了解这些疾病的病理也是至关重要的。