Cellular and Molecular Characterization of Auxin Receptors

生长素受体的细胞和分子表征

• 批准号: 9220080
• 负责人: Alan Jones
• 金额: $ 29万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1996-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9220080&HistoricalAwards=false
• 关键词: Cellular; Molecular; Characterization; Auxin; Receptors

Auxins are a class of growth hormone found in plants that induce cells to elongate. They act rapidly through the mediation of a single receptor or multiple receptors to cause changes in cell wall properties and gene expression. There are now several candidate auxin receptors in plants; however, their roles in growth and development have not yet been determined. These putative receptors are therefore designated "auxin-binding proteins" (ABP's). This project focuses on the characterization of two such ABP's, designated ABP1 and 65-kDa ABP. ABP1 is an endoplasmic reticulum (ER) protein that contains an ER-retention sequence; yet, this laboratory has demonstrated that a significant amount of this protein escapes the ER retention mechanism and uniquely migrates to the plasma membrane / cell wall space. This cell wall localization is consistent with its postulated site of action. The 65-kDa subunit ABP, recently identified in this laboratory using anti- idiotypic antibodies, is a nuclear localized protein. Preliminary data suggest that it binds DNA. The hypothesis is put forward that this putative receptors is involved in auxin-regulated gene transcription. %%% It has been known for many years that plant growth and development is regulated by plant hormones, principally auxins (e.g., indole acetic acid, or IAA) and cytokines. However, despite a great deal of effort, it is not yet understood how plant hormones exert their effects at a molecular level. Auxin-binding proteins, such as ABP1 and the 65-kDa ABP which are the subject of this project, have been described, but it has not yet been established for any of these that they are functional "auxin receptors," let alone mechanisms of action. This laboratory has made some very interesting and novel findings, such as the auxin-dependent subcellular localization of ABP1 and the nuclear localization and DNA binding characteristics of 65-kDa ABP, which may lead to breakthroughs in this area. An understanding of how plant cell growth and development is normally controlled or modulated by plant hormones is critical to this nation's agricultural biotechnology efforts.

生长素是植物中发现的一类生长激素，能诱导细胞伸长。它们通过单一受体或多个受体的介导迅速起作用，引起细胞壁特性和基因表达的变化。现在植物中有几种候选的生长素受体；然而，它们在生长和发育中的作用尚未确定。因此，这些假定的受体被称为“生长素结合蛋白”（ABP’s）。本项目重点研究了两种ABP的特征，分别是ABP1和65-kDa ABP。ABP1是一种内质网（ER）蛋白，含有ER保留序列；然而，本实验室已经证明，大量的这种蛋白质逃脱了内质网保留机制，并独特地迁移到质膜/细胞壁空间。这种细胞壁定位与假定的作用部位一致。65-kDa亚基ABP，最近在该实验室使用抗独特型抗体鉴定，是一种核定位蛋白。初步数据表明它能结合DNA。我们提出了这一假设受体参与生长素调控的基因转录。多年来，人们已经知道植物的生长发育受植物激素的调节，主要是生长素（如吲哚乙酸或IAA）和细胞因子。然而，尽管付出了巨大的努力，人们仍然不了解植物激素是如何在分子水平上发挥作用的。生长素结合蛋白，如ABP1和65-kDa ABP，是这个项目的主题，已经被描述过，但还没有确定它们是功能性的“生长素受体”，更不用说作用机制了。本实验室已经取得了一些非常有趣和新颖的发现，如ABP1的生长素依赖性亚细胞定位和65-kDa ABP的核定位和DNA结合特性，这些可能会导致该领域的突破。了解植物细胞的生长和发育通常是如何由植物激素控制或调节的，对这个国家的农业生物技术工作至关重要。