Auxin Biosynthesis and Signaling Mechanisms.

生长素生物合成和信号传导机制。

• 批准号: 6918509
• 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/6918509
• 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）：生长素是迄今为止发现的第一种植物激素，它几乎涉及植物生长发育的各个方面。生长素已经被研究了一个多世纪，但促进其生物活性的分子机制仍然知之甚少。我们甚至不清楚植物是如何产生生长素的，更不用说这个过程是如何受到发育和环境信号的调节了。生长素生物合成知识的缺乏进一步模糊了我们对生长素介导的信号转导的理解。本文提出的主要目的是分离和表征以前未识别的生长素生物合成和信号传导成分。我们已经描述了一个生长素过量产生的显性突变体，丝兰，这为我们提供了一个独特的机会来设计新的策略来研究生长素相关的过程。YUCCA是含黄素单加氧酶（FMO）超家族的一员，它催化生长素生物合成的一个限速步骤。生长素生物合成和信号传导的其他成分可以从丝兰抑制因子和丝兰样突变体的遗传筛选中分离出来。生物化学方法可用于鉴定YUCCA相关蛋白。本提案的第一个具体目的是表征丝兰抑制因子。其次，我们建议通过反向遗传学进一步明确YUCCA基因家族的作用。第三，我们将使用生化方法来检查YUCCA相关蛋白。第四，我们将进一步描述我们已经确定的尤卡样突变体。第五，也是最后，我们建议使用化学遗传学来表征sir1，这是一个对sirtinol不敏感的突变体，显示出已知生长素诱导基因的组成激活。这些研究是多学科性质的，将对生长素调控过程的机制产生重要的新见解，这些过程对植物生物学具有至关重要的意义。明确生长素在植物生长发育中的作用将最终对农业产生重大影响。最后，提出的研究将增加我们对其他真核生物复杂信号机制的理解，特别是在色氨酸稳态领域，这对包括人类在内的大多数生物都是必不可少的。