I am currently a Member of the Ludwig Institute for Cancer Research and Professor of Cellular and Molecular Medicine at the University of California, San Diego (UCSD) School of Medicine. I am also a co-director of the UCSD Bioinformatics and Systems Biology Graduate Program.

My research is devoted to the understanding of gene regulatory mechanisms and chromatin organization in mammalian cells. My lab is taking an integrative approach that combines genomics and computational tools to study the transcriptional regulatory networks in human cells in normal and disease states. We discovered signature chromatin modification patterns at transcriptional enhancers, and proposed a chromatin-modification-signature based enhancer mapping strategy for annotation of these regulatory sequences in genomes. We further demonstrated that cell type specific activities of enhancers correlate with their chromatin modification states, a finding that set the stage for global analysis of gene regulatory mechanisms during mammalian development.

In recent years, we also investigated the molecular architecture of chromatin in mammalian cells and made several key discoveries: 1) we found that the genome is partitioned into thousands of megabase-sized “topological domains”, a structural feature that is highly conserved during development and through evolution; 2) we showed that topological domains are units of genome organization that physically constrain the long-range regulatory interactions between enhancers and their target genes; and, 3) we demonstrated that the cis regulatory elements and transcription factors regulate the formation of topological domains.