The cell nucleus is a self-organized structure. In mitotic human cells, the nucleus breaks down and reassembles during each cell division. The nuclear envelope, the barrier separating the nucleoplasm and the cytoplasm, can spontaneously repair itself if it is damaged. Almost two meters of genomic DNA are compacted into the nucleus, organized into DNA-protein complexes called chromosomes. Chromosomes in the nucleus are continuously in motion, subject to forces which tether different regions of the genome together, and to the nuclear envelope, while diverse molecular motors extrude DNA loops and induce DNA sliding. Nuclear RNAs aggregate with proteins to form small clusters and large nuclear bodies, dynamically interacting with chromosomes.

We are studying the dynamics and mechanics of the nucleus, with a focus on understanding how cellular scale behaviors of chromosomes result from molecular and meso scale processes. A key question concerns the relative importance of sequence specific, heterogeneous properties vs more generic polymer and material physics. We are investigating the biophysics of transcription and the interplay between transcription regulation and chromosome mechanics. We are also exploring the biomechanics of the nuclear envelope, and nuclear rupture and repair.