Auxin Biosynthesis and Signaling Mechanisms.

生长素生物合成和信号传导机制。

• 批准号: 6673644
• 负责人: YUNDE ZHAO
• 金额: $ 29.49万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6673644
• 关键词: Arabidopsis; biological signal transduction; chemical genetics; gene expression; gene mutation; genetic screening; green fluorescent proteins; hormone biosynthesis; in situ hybridization; indoleacetate; mass spectrometry; microarray technology; molecular cloning; northern blottings; oxygenases; phytohormones; plant genetics; plant growth /development; plant proteins; polymerase chain reaction; protein purification; proteomics; regulatory gene; western blottings; yeast two hybrid system

DESCRIPTION (provided by applicant): Auxin was the first plant hormone ever identified, and it has been implicated in almost every aspect of plant growth and development. Auxin has been studied for over a century, but the molecular mechanisms that promote its biological activities remain poorly understood. It is not even clear how auxin is produced by plants, let alone how that process is regulated by developmental and environmental signals. This lack of knowledge of auxin biosynthesis further clouds our understanding of auxin-mediated signal transduction. The major objective of the work proposed herein is to isolate and characterize previously unidentified components of auxin biosynthesis and signaling. We have characterized a dominant auxin overproduction mutant, yucca, and this provides us with a unique opportunity to design new strategies to examine auxin-related processes. YUCCA is a member of the flavin-containing monooxygenase (FMO) superfamily, and it catalyzes a rate-limiting step in auxin biosynthesis. Additional components of auxin biosynthesis and signaling can be isolated from genetic screens for yucca suppressors and yucca-like mutants. Biochemical approaches can be utilized to identify YUCCA associated proteins. The first specific aim of this proposal is to characterize yucca suppressors. Second, we propose to further define the roles of the YUCCA gene family by using reverse genetics. Third, we will use biochemical approaches to examine YUCCA associated proteins. Fourth, we will further characterize yucca-like mutants that we have already identified. Fifth and finally, we propose to use chemical genetics in our characterization of sir1, a mutant insensitive to sirtinol that shows constitutive activation of known auxin-inducible genes. These studies are multi-disciplinary in nature and should yield significant new insights into the mechanisms of auxin regulated processes and these processes are of paramount importance to plant biology. A clear understanding of auxin's role in plant growth and development will ultimately have significant agricultural impact. Finally, the proposed study will augment our understanding of complex signaling mechanisms in other eukaryotes, particularly in the area of tryptophan homeostasis, which is essential to most organisms, including humans.

描述（由申请人提供）：生长素是有史以来第一个植物激素，它几乎涉及植物生长和发育的各个方面。生长素已经研究了一个多世纪，但是促进其生物学活性的分子机制仍然很少理解。甚至还不清楚生长素是如何由植物产生的，更不用说该过程是如何通过发育和环境信号调节的。对生长素生物合成的缺乏知识进一步掩盖了我们对生长素介导的信号转导的理解。本文提出的工作的主要目的是隔离和表征先前未鉴定的生长素生物合成和信号传导的成分。我们已经描述了一个主要的生长素过量生产突变体丝兰，这为我们提供了一个独特的机会，可以设计新的策略来检查与生长素相关的过程。丝兰是含黄素单加氧酶（FMO）超家族的成员，它在生长素生物合成中催化了限速步骤。生长素生物合成和信号传导的其他成分可以从丝菌抑制剂和丝兰样突变体中分离出来。可以利用生化方法来鉴定丝兰相关的蛋白质。该提案的第一个具体目的是表征丝兰抑制器。其次，我们建议通过使用反向遗传学进一步定义丝兰基因家族的作用。第三，我们将使用生化方法检查丝兰相关蛋白。第四，我们将进一步表征我们已经确定的类似丝兰的突变体。第五和最后，我们建议在SIR1的表征中使用化学遗传学，这是对Sirtinol的突变体不敏感的，显示出已知的生长素诱导基因的本构激活。这些研究本质上是多学科的，应该对生长素调节过程的机制产生重大的新见解，这些过程对植物生物学至关重要。对生长素在植物生长和发展中的作用的清晰了解最终将产生重大的农业影响。最后，拟议的研究将增强我们对其他真核生物中复杂信号机制的理解，特别是在色氨酸稳态领域，这对于大多数生物（包括人类）至关重要。