Molecular mechanisms of auxin response in Arabidopsis

拟南芥生长素反应的分子机制

• 批准号: 6843749
• 负责人: WILLIAM M GRAY
• 金额: $ 21.95万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6843749
• 关键词: Arabidopsis; SDS polyacrylamide gel electrophoresis; biological signal transduction; gene expression; hormone regulation /control mechanism; immunoprecipitation; indoleacetate; mass spectrometry; mitogen activated protein kinase; molecular genetics; phosphorylation; plant extracts; plant genetics; plant growth /development; plant growth regulators; plant physiology; protein protein interaction; ubiquitin; western blottings; yeast two hybrid system

DESCRIPTION (provided by applicant): The hormone auxin regulates virtually every aspect of plant growth and development. Genetic and molecular studies with Arabidopsis have defined the SCFTIR1 ubiquitin-ligase complex as a positive regulator of auxin response. Recent findings indicate that auxin promotes SCFTIR1-mediated ubiquitination of the Aux/IAA proteins, a large family of transcriptional regulators which negatively regulate auxin response. The subsequent proteasome-mediated degradation of the Aux/IAAs derepresses the auxin response pathway resulting in changes in growth and development. We have shown that Aux/IAA proteins physically interact with the SCFTIR1 complex in crude seedling extracts. Auxin promotes Aux/IAA degradation by targeting these factors to the SCFTIR1 ubiquitin-ligase by an undetermined mechanism. Elucidation of how auxin regulates this interaction will provide important information into the signaling events of the auxin response pathway upstream of the SCFTIR1 ubiquitin-ligase. The long-term goal of the proposed research is to understand the molecular mechanisms underlying auxin regulation of plant growth and development. The identification of the mechanisms underlying auxin action will provide new tools for modulating auxin response for agricultural and horticultural benefit. Further, since SCF-mediated ubiquitination is highly conserved, these studies will contribute toward our understanding of this mode of cellular regulation in all eukaryotes. The specific objectives of this proposal include; 1) elucidation of the nature and regulation of protein-protein interactions between the Aux/IAA transcriptional regulators and the SCFTIR1 ubiquitin-ligase complex; 2) the genetic and molecular analysis of a new class of Arabidopsis mutants defective in auxin response; 3) the molecular characterization of a mutant derivative of the AtCUL1 SCF subunit; and 4) investigate the biological significance of the interaction between the AXR2 Aux/IAA protein and the COP9 signalosome subunit CSN5.

描述（申请人提供）：激素生长素调节植物生长和发育的几乎每一个方面。拟南芥的遗传学和分子生物学研究已经将SCFTIR 1泛素连接酶复合物确定为生长素反应的正调控因子。最近的研究表明，生长素促进SCFTIR 1介导的Aux/IAA蛋白的泛素化，Aux/IAA蛋白是负调节生长素反应的转录调节因子的大家族。随后的蛋白酶体介导的Aux/IAAs的降解解抑制生长素反应途径，导致生长和发育的变化。我们已经表明，Aux/IAA蛋白质物理相互作用的SCFTIR 1复杂的粗幼苗提取物。生长素促进Aux/IAA降解的靶向这些因素的SCFTIR 1泛素连接酶通过一个未确定的机制。阐明生长素如何调节这种相互作用将提供重要的信息到生长素反应途径上游的SCFTIR 1泛素连接酶的信号事件。该研究的长期目标是了解生长素调控植物生长和发育的分子机制。生长素作用机制的确定将为调节生长素对农业和园艺效益的反应提供新的工具。此外，由于SCF介导的泛素化是高度保守的，这些研究将有助于我们了解这种模式的细胞调节在所有真核生物。本研究的主要目的包括：1）阐明Aux/IAA转录调控因子与SCFTIR 1泛素连接酶复合物之间蛋白质-蛋白质相互作用的性质和调控; 2）对一类新的拟南芥生长素应答缺陷突变体进行遗传和分子分析; 3）对AtCUL 1 SCF亚基突变衍生物进行分子鉴定;研究AXR 2 Aux/IAA蛋白与COP 9信号体亚基CSN 5相互作用的生物学意义。