CAREER: Dissecting Phase Behavior of Pioneer Transcription Factor Condensates and Their Role in Gene Regulation

DNA molecules which pack together to form chromosomes, store the information for life, like a computer hard drive. Genes are the bits of information, which are generally turned ‘off’ until the information is needed. A special protein called a transcription factor (TF) turns a gene ‘on,’ ultimately leading to protein production and cellular function. Deciphering how TFs regulate gene expression is of fundamental importance to understanding their function in the development of a multicellular organism. This project will test the hypothesis that, much like dew drops on a spider web, the TFs form liquid-like droplets on the DNA where each droplet may provide a special environment that regulates gene expression. This project will provide key new knowledge in the field of gene regulation. The education plan of the project aims to train the next generation of biophysicists in cross-disciplinary education and research by inspiring high-school students from the Buffalo Public School District to consider STEM career options through accessible science as well as promoting biophysics literacy among lay audiences through local and global art exhibitions. Gene expression is crucial for determining a cell’s fate even though many genes that need to be expressed are rendered inaccessible by compaction into dense chromatin. Pioneer Transcription Factors (PTFs) can initiate chromatin remodeling into an accessible state. We hypothesize that this activity is facilitated by the formation of phase-separated hubs containing TFs, RNA polymerases, and protein complexes responsible for nucleosome remodeling. This project aims to determine the physical principles that govern the phase separation of PTFs and how the co-condensation of PTFs with DNA and other requisite cofactors regulates their activity. The proposed studies are expected to provide new insights into (a) the role of phase separation in genome organization, and (b) the mechanism of gene regulation by pioneer transcription factors. Synergistic educational, outreach and training activities complement the research and include engagement with undergraduate students, high school students and the lay public. Completing the project goals will directly contribute to the PI’s long-term research objective to uncover molecular mechanisms of genome organization via biomolecular phase transitions. This project is jointly funded by the Molecular Biophysics and Genetic Mechanisms programs of the Molecular and Cellular Biosciences Division in the Biological Sciences Directorate. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.