Modulation of Plant Transcription Factor Function by Small Molecules

该项目的目标是揭示一种新型的反馈调节（一种小化学分子调节其自身生产的机制），这种反馈调节是由一个分子与控制该分子生产的主蛋白质调节因子结合而介导的。该项目将有助于博士后科研人员的科学和专业发展，并将为本科生提供研究经验。该项目包括开发定量生物化学夏季实践研讨会，这将使本科生和研究生、博士后研究人员和初级教师受益。在玉米中，R蛋白是激活紫色花青素类黄酮生物合成途径中编码酶基因转录的转录因子。初步数据表明，类黄酮分子通过特定的蛋白结构域（ACT结构域）与R结合，调节蛋白-蛋白相互作用和R蛋白的dna结合能力，进而导致与类黄酮途径相关的基因启动子的差异识别。该模型的实验测试将：1)建立R与已确定的与ACT结合的黄酮类化合物相互作用的体内结果；2)研究ACT-小分子结构-功能关系，定义哪些小分子与ACT结合，确定与小分子相互作用相关的ACT残基，并确定其他植物转录因子中ACT结构域的普遍性；3)通过结合遗传资源和细胞方法，分析R的ACT结构域控制的体内动态关联，研究在黄酮类化合物或其他小分子存在和不存在的情况下，相互作用发生在哪里和哪些地方。这项工作有望揭示一种新型的反馈调节机制（代谢物结合调节负责配体合成的转录因子），这可以作为其他小代谢物如何调节自身合成的模型。该项目由生物科学理事会（分子和细胞生物科学部的遗传机制项目；综合有机系统部的植物基因组研究项目）和数学和物理科学理事会（化学部的生命过程化学项目）共同资助。

The goal of this project is to reveal insights into a novel type of feedback regulation (a mechanism by which a small chemical molecule can regulate its own production) mediated by the binding of a molecule to the master protein regulator controlling the production of that molecule. The project will contribute to the scientific and professional development of postdoctoral fellows and will provide research experiences for undergraduate students in research. The project includes the development of a Summer Practical Workshop in Quantitative Biochemistry, which will benefit both undergraduate and graduate students, postdoctoral researchers, and junior faculty.In corn, the R protein is a transcription factor that activates transcription of genes encoding enzymes in the flavonoid biosynthetic pathway for purple anthocyanin pigments. Preliminary data suggest that binding of flavonoid molecules to R, through a specific protein domain (the ACT domain), modulates the protein-protein interactions and the DNA-binding abilities of the R protein, leading in turn to differential recognition of promoters in the genes involved in the flavonoid pathway. Experimental tests of this model will: 1) Establish the in vivo consequences of the interaction of R with flavonoids that have been identified to bind to the ACT; 2) Investigate ACT-small molecule structure-function relationships, by defining which other small molecules bind to the ACT, identifying the ACT residues relevant for the small molecule interaction, and establishing how general the results are for ACT domains in other plant transcription factors; and 3) Analyze in vivo the dynamic associations controlled by the ACT domain of R, by combining genetic resources with cellular approaches to investigate where and which interactions occur, in the presence and absence of flavonoids or other small molecules. The work is expected to reveal a new type of feedback regulatory mechanism (metabolite binding regulating a transcription factor responsible for synthesis of the ligand), which could serve as a model for how other small metabolites might regulate their own synthesis. This project is co-funded by the Directorate for Biological Sciences (Genetic Mechanisms Program in the Division of Molecular and Cellular Biosciences; Plant Genome Research Program in the Division of Integrative Organismal Systems) and by the Directorate for Mathematics and Physical Sciences (Chemistry of Life Processes Program in the Division of Chemistry).