Molecular Genetics of Auxin Action

生长素作用的分子遗传学

• 批准号: 7675078
• 负责人: MARK A ESTELLE
• 金额: $ 25.54万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-08-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7675078
• 关键词: Arabidopsis; Auxins; Binding; Biochemical; Collaborations; Defect; Development; Embryo; Family; Gene Expression Profile; Genes; Genetic Screening; Genetic Transcription; Goals; Grant; Growth; Hormones; Human; Mediating; Molecular Genetics; Numbers; Plant Growth Regulators; Plant Roots; Process; Proteins; Regulation; Signal Transduction; Structure; Ubiquitin-Protein Ligase Complexes; cell type; gene function; insight; mutant; novel; plant growth/development; protein degradation; research study; response; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): The plant hormone auxin is involved in virtually all aspects of plant growth and development. During the last grant period we demonstrated that auxin acts by stimulating the degradation of a family of transcriptional repressers called the AUX/IAA proteins, a process that requires the ubiquitin protein ligase SCFTIR1 and related SCFs. In our most recent studies we have shown that auxin interacts directly with SCFTIR1 or a closely associated protein. We propose that auxin binding promotes the interaction between SCFTIR1 and its' substrates, the AUX/IAA proteins. This is a novel mechanism of hormone action and SCF regulation. The current proposal has three specific aims. The first is to investigate auxin regulation of AUX/IAA degradation. The region of TIR1 that is required for AUX/IAA recognition will be identified. Biochemical experiments will be conducted to identify and characterize proteins that mediate AUX/IAA recognition and in particular the direct target of auxin action will be defined. Further, the structure of the AUX/IAA proteins will be determined in collaboration with my colleague, Dr. L. Chen. In the second aim we will characterize the Arabidopsis root transcriptome. The goals of this aim are to identify downstream targets of AUX/IAA regulation and to compare and contrast auxin regulated transcription in cell types with different auxin growth responses. A number of candidate auxin-response genes have been identified and these will be characterized. In the third aim, we will conduct novel genetic screens for new mutants deficient in auxin response. Our emphasis will be on mutants with severe defects in embryo and root development that are unlikely to be recovered in previous screens. We expect our experiments to provide fundamental new insight into the mechanism of auxin action. Further, our studies indicate that auxin acts through a novel mechanism that involves direct binding to a ubiquitin protein ligase. These results will have significant impact on studies of protein degradation in diverse species including humans.

描述（由申请人提供）：植物激素生长素几乎参与植物生长和发育的所有方面。在上一次资助期间，我们证明了生长素通过刺激称为 AUX/IAA 蛋白的转录抑制蛋白家族的降解来发挥作用，这一过程需要泛素蛋白连接酶 SCFTIR1 和相关的 SCF。在我们最近的研究中，我们发现生长素直接与 SCFTIR1 或密切相关的蛋白质相互作用。我们认为生长素结合促进 SCFTIR1 与其底物 AUX/IAA 蛋白之间的相互作用。这是激素作用和 SCF 调节的新机制。当前的提案有三个具体目标。第一个是研究生长素对 AUX/IAA 降解的调节。将识别 AUX/IAA 识别所需的 TIR1 区域。将进行生化实验来鉴定和表征介导 AUX/IAA 识别的蛋白质，特别是确定生长素作用的直接目标。此外，AUX/IAA 蛋白的结构将与我的同事 L. Chen 博士合作确定。在第二个目标中，我们将描述拟南芥根转录组的特征。该目的的目标是确定 AUX/IAA 调节的下游靶标，并比较和对比具有不同生长素生长反应的细胞类型中生长素调节的转录。已经鉴定了许多候选生长素反应基因，并将对其进行表征。在第三个目标中，我们将对缺乏生长素反应的新突变体进行新的遗传筛选。我们的重点将是在胚胎和根发育方面具有严重缺陷的突变体，这些缺陷在以前的筛选中不太可能恢复。我们期望我们的实验能够为生长素作用机制提供基本的新见解。此外，我们的研究表明，生长素通过一种新的机制发挥作用，该机制涉及直接结合泛素蛋白连接酶。这些结果将对包括人类在内的不同物种的蛋白质降解研究产生重大影响。