CAREER: Formation and Regulation of Chromatin-Associated Condensates

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Cells contain membrane-enclosed compartments to organize biochemical reactions. Cells also create membrane-less compartments, referred to as biomolecular condensates, to concentrate proteins and RNAs. Some condensates are formed at specific locations, including on cellular structures such as chromosomal DNA. However, site-specific regulation of condensate nucleation, growth, composition, and fluidity, which are essential for condensate functions, remain largely unknown. Using a novel chemoptogenetic tool based on light-sensitive chemicals to manipulate condensates in live cells, this project will uncover the general principles underpinning the formation and regulation of protein and RNA condensates on chromosomal DNA. This project will engage high school students in the research by doing experiments with students in the Carnegie Mellon University Academic Cloud Lab, a state-of-the-art science laboratory that students can access from a web portal. In addition, the established curriculums will be available for other educators and students with internet access so more students can learn science by doing science. American Rescue Plan funding is used to support this early career investigator at a critical stage in his career. Liquid-liquid phase separation is implicated in the formation of many chromatin-associated condensates, including nucleoli, transcription hubs, and DNA repair foci. However, our understanding of the phase separation process, the regulation of condensate properties, and the relevance of phase separation in chromatin functions of many chromatin-associated condensates are still limited. This project will combine chemoptogenetic manipulation in live cells with biophysical quantification and biochemical assays to determine the necessary and sufficient conditions for protein and RNA phase separation on chromatin in the nuclear milieu, reveal how the nuclear environment and active signaling control condensate growth, and dissect how condensate chemical and material properties arise from molecular interactions. Results from this project will help determine whether and how protein and RNA phase separation contribute to chromatin functions. 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.