A Reaction-Driven Condensate-to-Vesicle Transition Selects, Activates, and Spatially Organizes RNA

Abstract

Living systems depend on the selective concentration of informational polymers within membrane-bound compartments. Liquid-liquid phase-separated condensates efficiently concentrate biomolecules, whereas membrane-bound vesicles provide persistent compartment boundaries. However, direct chemical mechanisms that couple these organizational states remain largely unexplored. Here we report a reaction-driven pathway linking condensates to RNA-enriched lipid vesicles. Electrostatic interactions between cationic thioesters and RNA drive phase separation into reactive condensates. Reaction with cysteine generates membrane lipids and transforms the condensates into unilamellar bilayer vesicles with near-uniform size distribution. The vesicles encapsulate >90% of the RNA from the initial solution and concentrate it by more than two orders of magnitude to >100 {micro}M. Encapsulation is strongly dependent on RNA length, with short oligonucleotides excluded while longer RNAs are selectively retained. Under spatial gradients of the chemical trigger, sharply defined vesicle populations with distinct RNA compositions emerge. Reaction-driven compartmentalization raises local ribozyme and substrate concentrations above the threshold required for catalytic activity, enabling function from otherwise inactive dilute solutions. These findings establish a mechanism by which chemical reactions generate selective, functional, and spatially organized RNA-enriched membrane-bound compartments from heterogeneous molecular mixtures.