Our lab is interested in biochemical mechanisms of chromatin based epigenetic inheritance of gene regulatory information. It is becoming increasingly clear that chromatin structure (nucleosome position, composition and modification, chromatin folding, and chromatin associated proteins) is important in many gene regulatory events. It is widely hypothesized that modifications to chromatin can serve as heritable information but exactly how chromatin modifications can be inherited through the disruptive events in cell division, namely DNA replication and mitosis, is not yet known. Our goal is to reconstitute passage of gene regulatory information through steps in the cell cycle in vitro. As we uncover biochemical mechanisms specifically involved in inheritance of chromatin based information, we will test the role these mechanisms play in vivo. We study the Polycomb and trithorax proteins, which are thought to use changes in chromatin structure to maintain gene expression states. Our work on Polycomb proteins includes dissecting how these proteins can non-covalently modify chromatin structure, how these proteins behave during chromatin replication and in mitosis, and how gene silencing mediated by Polycomb proteins can be reversed. We also ask basic questions about how the primary structure of chromatin (nucleosomes, their positions and modifications) behaves during DNA replication. We use a range of biochemical, molecular biological, and cell biological techniques to tackle these questions.