The Weber lab uses quantitative live-cell imaging and physical modeling to understand how biological systems establish and dynamically regulate spatial organization. Currently, we are focused on the process of intracellular phase separation, which governs the assembly and function of various membraneless organelles. We study this process in three distinct but complementary systems: clusters of RNA polymerase in the bacterium Escherichia coli; nucleoli in the nematode Caenorhabditis elegans; and condensed chromosomes in the symbiotic alga Breviolum minutum. Ultimately, we are interested in determining how these condensed-phase organelles regulate gene expression, and impact the growth, size and health of individual cells, multicellular organisms, and ecological communities.