Three-dimensional modeling dynamics of nuclear organization*

The eukaryotic genome' intranuclear order is physically established through the hierarchical compartmentalization of nuclear chromatin, which is strongly coupled with gene regulatory activities. The mechanistic underpinnings of chromatin compartmentalization, its dynamics, and its impact on gene regulatory processes are, however, still poorly understood. Understating the principles that control the dynamics and the spatial regulation of chromatin droplets formation is a possible way to elucidate the relationship between chromatin compartmentalization patterns and gene regulation. Here, we present a multiphasic liquid model of nucleus to study the 3D chromatin organization dynamics. The model accounts for various subcompartments chromatin interactions as well as differential interactions between heterochromatin and nuclear Lamina, and dynamically nuclear geometry change. We show the ability of our model to predict various nuclear morphologies at a large-length scale depending on the cell types and stages of the life-cycle of cells. Comparing the imaging experiments and 3D simulations of the example of a genetic Drosophila nucleus has demonstrated excellent agreement.