A central challenge in mammalian biology is how a single genome conducts a wide variety of cell states by orchestrating unique gene expression programs. The epigenetic and topologic organization of the genome facilitates transcriptional programs that define cell identity and allow cells to respond to their environment. This organization spans multiple genomic length scales and includes features such as DNA methylation, histone modifications, chromatin loops, topologically associated domains (TADs) and chromatin compartments (see Figure). Each of these structures correlates to transcription but the precise causal relationships remain incompletely understood. Our lab investigates how DNA structure contributes to transcriptional programs in normal physiology and disease.

Currently our research program is grounded in two main areas:

Defining functional relationships between 3D genome structure and transcription:
Ongoing projects include studying how insulin signaling and hypoxia bring signals to the genome to restructure its organization and execute responsive transcriptional programs. We define how the genome is spatially reorganized upon these external signals and how this reorganization contributes to gene expression changes. Other work includes creating isogenic models with large-scale changes to their DNA methylomes to investigate the mechanisms by which DNA methylation patterns impact the 3D genome and gene expression programs. 

A Micro-C contact map of mouse liver cells

MDM2, a p53 inhibitor (labelled in red) coats large neochromosomes in a soft tissue sarcoma cell line
Nuclear reorganization in cancer:
A significant portion of the lab is also dedicated to the study of genome organization in cancer. For over a century, pathologists have used nuclear structure to diagnose and subtype cancer.  The most consistent histomorphologic feature of malignant cells is nuclear atypia.  Nuclei of cancer cells are enlarged, have irregular shapes and abnormal chromatin.  This feature can even distinguish one type of cancer from another.  Nevertheless, the molecular underpinnings of these changes are poorly understood.

Our lab seeks to define how the 3D genome is altered in cancer and the impact that these alterations have on tumor cell phenotype. In cancer cells, epigenetic and topologic processes can be altered to drive malignant gene expression programs. We are investigating how architectural protein mutations reshape the 3D genome in high grade serous ovarian cancer using engineered tumor models and primary tumor samples. Additionally, we are interrogating how large-scale chromosomal alterations contribute to oncogene amplification in sarcoma and the role of these alterations in contributing to tumor evolution.