Molecular mechanisms of auxin response in Arabidopsis

拟南芥生长素反应的分子机制

• 批准号: 6693316
• 负责人: WILLIAM M GRAY
• 金额: $ 22.49万
• 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/6693316
• 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（由申请人提供）：生长素激素几乎调节植物生长和发育的各个方面。对拟南芥的遗传和分子研究已将 SCFTIR1 泛素连接酶复合物定义为生长素反应的正调节因子。最近的研究结果表明，生长素促进 SCFTIR1 介导的 Aux/IAA 蛋白泛素化，Aux/IAA 蛋白是一个负调节生长素反应的转录调节因子大家族。随后蛋白酶体介导的 Aux/IAA 降解会抑制生长素反应途径，从而导致生长和发育的变化。我们已经证明 Aux/IAA 蛋白与粗幼苗提取物中的 SCFTIR1 复合物发生物理相互作用。生长素通过一种未确定的机制将这些因子靶向 SCFTIR1 泛素连接酶，从而促进 Aux/IAA 降解。阐明生长素如何调节这种相互作用将为 SCFTIR1 泛素连接酶上游生长素响应途径的信号事件提供重要信息。该研究的长期目标是了解生长素调节植物生长和发育的分子机制。植物生长素作用机制的识别将为调节植物生长素反应以获得农业和园艺效益提供新的工具。此外，由于 SCF 介导的泛素化高度保守，这些研究将有助于我们了解所有真核生物中的这种细胞调节模式。该提案的具体目标包括： 1) 阐明Aux/IAA转录调节因子和SCFTIR1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节； 2）一类新的生长素反应缺陷的拟南芥突变体的遗传和分子分析； 3) AtCUL1 SCF 亚基突变衍生物的分子表征； 4) 研究 AXR2 Aux/IAA 蛋白与 COP9 信号体亚基 CSN5 之间相互作用的生物学意义。