Biomolecular condensates as arbiters of biochemical reactions inside the nucleus

Liquid-liquid phase separation (LLPS) has emerged as a central player in the assembly of membraneless compartments termed biomolecular condensates. These compartments are dynamic structures that can condense or dissolve under specific conditions to regulate molecular functions. Such properties allow biomolecular condensates to rapidly respond to changing endogenous or environmental conditions. Here, we review emerging roles for LLPS within the nuclear space, with a specific emphasis on genome organization, expression and repair. Our review highlights the emerging notion that biomolecular condensates regulate the sequential engagement of molecules in multistep biological processes. Laflamme and Mekhail discuss emerging nuclear roles for LLPS in genome organization, gene expression and DNA repair, highlighting the emerging notion that biomolecular condensates regulate the sequential engagement of molecules in multistep biological processes.