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（由申请人提供）：激素生长素几乎调节植物生长和发育的各个方面。用拟南芥的遗传和分子研究已将SCFTIR1泛素 - 岩合酶复合物定义为生长素反应的阳性调节剂。最近的发现表明，生长素促进了AUX/IAA蛋白的SCFTIR1介导的泛素化，这是一个大量的转录调节剂，对生长素反应负面调节。随后的蛋白酶体介导的AUX/IAAS的降解导致生长素反应途径导致生长和发育的变化。我们已经表明，在粗幼苗提取物中，AUX/IAA蛋白与SCFTIR1复合物在物理上相互作用。生长素通过不确定的机制将这些因素靶向SCFTIR1泛素 - 岩性酶来促进AUX/IAA降解。阐明生长素如何调节这种相互作用将为SCFTIR1泛素 - 岩酶上游的生长素反应途径的信号事件提供重要信息。拟议的研究的长期目标是了解植物生长和发育的生长素调节的分子机制。生长素作用基础机制的识别将提供新工具，以调节生长素反应以供农业和园艺利益。此外，由于SCF介导的泛素化是高度保守的，因此这些研究将有助于我们理解所有真核生物中这种细胞调节的方式。该提案的具体目标包括： 1）阐明AUX/IAA转录调节剂与SCFTIR1泛素 - 连接酶复合物之间蛋白质蛋白相互作用的性质和调节； 2）新的拟南芥突变体在生长素反应中有缺陷的遗传和分子分析； 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。