Structure and Dynamics of Histone-DNA Phase Separated Liquid Droplets

Liquid-liquid phase separation of biological and synthetic polymers due to multivalent interactions is a known problem in polyelectrolyte physics. Currently there is a revived interest in fully understanding this phenomenon as its importance to cell biology has become increasingly clear. Here, we show that histones, owing to their intrinsically disordered regions, phase separate into highly dynamic liquid droplets in the presence of DNA. We also employ state-of-the-art super-resolved fluorescence microscopy techniques to gain unique access into the nanoscopic structural organization and dynamics of the liquid droplets. We find that the diffusive dynamics of small molecules within histone-DNA liquid droplets is non-Fickian (subdiffusive). Such transport mechanism can have significant implications in genome biology, in particular transcription kinetics and regulation of chromatin.