Kristin Knouse, MD, PhD
Assistant Professor of Biology; Intramural Faculty, Koch Institute
MIT
Delivering insights into organ homeostasis and regeneration through in vivo genome-wide screens
Our ability to understand and modulate mammalian physiology and disease requires knowing how all genes contribute to any given phenotype in the organism. Genome-wide screening using CRISPR-Cas9 has emerged as a powerful method for the genetic dissection of cellular processes, but the need to stably deliver single guide RNAs to millions of cells has largely restricted its implementation to ex vivo systems. These ex vivo systems cannot reproduce all of the cellular phenotypes observed in vivo nor can they recapitulate all of the factors that influence these phenotypes. There thus remains a pressing need for high-throughput functional genomics in a living organism. Here, we establish accessible genome-wide screening in the mouse liver and use this approach to uncover the complete regulation of cellular fitness in a living organism. We discover extracellular regulation of cellular fitness not observed in cell culture systems. Our approach provides a comprehensive picture of cell fitness in a living organism and highlights the importance of investigating cellular phenomena in their native context. Our screening method is robust, scalable, and easily adapted to examine diverse cellular processes using any CRISPR application. We have hereby established a foundation for accessible high-throughput functional genomics in a living mammal, enabling unprecedented insight into mammalian physiology and disease.
