# Growth, Dissolution and Segregation of Genetically Encoded RNA Droplets by Ribozyme Catalysis

## TL;DR

Researchers created RNA droplets that can dissolve and regrow based on genetic instructions, a step toward building synthetic cells.

## Contribution

The study introduces RNA droplets with genetically encoded dissolution and regrowth cycles using ribozymes.

## Key findings

- RNA droplets can be programmed to dissolve at different rates using fast or slow ribozymes.
- Mixed droplet populations can be segregated through sequence-specific cleavage of a chimeric RNA linker.
- DNA templates within droplets enable regrowth, demonstrating a cycle of dissolution and regeneration.

## Abstract

Active droplets, membraneless compartments driven by internal chemical reactions, are compelling models for protocells and synthetic life. A central challenge is to program their dynamic behaviors using heritable genetic information, which would grant them the capacity to evolve. Here, we create transiently active RNA droplets by integrating sites for ribozyme catalysis directly into the sequence of self‐assembling, four‐arm RNA nanostars. To enable perfusion and observe the resulting dynamics over time, we develop a method for trapping individual droplets in hydrogel cages by targeted in situ photopolymerization. This enables us to quantify the sequence‐programmable droplet dissolution and to control the degradation kinetics by choosing between fast (hammerhead) and slow (hairpin) ribozymes. Furthermore, we trigger the segregation of mixed droplet populations via the sequence‐specific cleavage of a chimeric linker RNA. The droplet‐encapsulated DNA templates code for the regrowth of new droplets, establishing the proof‐of‐principle for a minimal, genetically encoded cycle of dissolution and regrowth. By directly linking RNA sequence to droplet stability, composition, and life‐cycle dynamics, our work provides a robust platform for engineering evolvable materials and advancing the bottom‐up construction of synthetic cells.

Ribozymes enable sequence‐encoded turnover of RNA droplet material, resulting in transiently active droplets that selectively segregate based on their genotype. This establishes a direct link between genetic information and droplet behavior, marking a step toward programmable, evolvable RNA‐based compartments with life‐like properties.