By displaying combinatorial patterns of chemical modifications, the nucleosome serves as a signaling hub in chromatin-templated processes, including gene expression, replication, and DNA damage repair. These processes are critical to the maintenance of cellular identity and genomic integrity and their misregulation is a hallmark of cancer and many developmental diseases. Despite this clear connection to human health, our understanding of nucleosome recognition by chromatin modifying enzymes and effectors of chromatin-templated processes is incomplete. Moreover, we lack fundamental molecular insights into how combinatorial chromatin modification signatures function and the interplay between chromatin modifications. These knowledge deficits are limiting in the development of therapeutics targeting chromatin processes. To address this unmet need, we are exploring mechanisms of nucleosome recognition and signaling on multiple scales. We have used proteomics to define the nucleosome interactome and identify two key regions on the nucleosome surface that dominant nucleosome binding. We are now exploring these regions at higher resolution and interrogating the role of chromatin modifications in tuning nucleosome interactions. Meanwhile, we are exploring mechanisms governing the interplay between histone modifications at near atomic resolution. By pairing semisynthetic designer nucleosomes with cryo-electron microscopy and X-ray crystallography, we propose to visualize chromatin enzymes in action on modified nucleosome substrates. Through these studies, we expect to define universal patterns of chromatin recognition and elucidate molecular mechanisms through which chromatin proteins function. Our research will enable hypothesis-driven functional studies in disease model systems and uncover new avenues for drug discovery.
Our genomes are packaged inside cells in the form of chromatin. The mission of this research is to understand how chromatin controls gene expression in normal cells and how this it is hijacked in diseases, especially cancer. We will accomplish this goal by visualizing how cellular factors that control gene expression function on chromatin.
