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).
