DNA Signal Induced Fusion And Aggregation Behaviors of Synthetic Cells

Cell fusion is regulated by snap receptor (SNARE) proteins in mammalian cells. The zippering of SNARE proteins exerts forces to the adjacent cell membrane and induces membrane fusion. The hybridization of membrane anchored DNA can induce fusion in a similar way. The advantage of using DNA as a fusion signal is that oligonucleotides are much easier to engineer and control. In this study, we construct two types of small vesicles decorated with DNA oligonucleotides and demonstrate their fusion using programmable DNA base-pairing. Fluorescent probes are used to measure fusion events. The experiment advances our understanding of the dynamic vesicle fusion behavior.

Cell aggregation is a complex behavior that is closely associated to the differentiation, migration, and viability of biological cells. An effort to create synthetic analogs could lead to considerable advances in cell physiology and biophysics. Rendering and modulating such a dynamic artificial cell system require mechanisms for receiving, transducing, and transmitting intercellular signals, yet effective tools are limited at present. Here we construct synthetic cells and show their programmable aggregation behaviors using DNA oligonucleotides as a signaling molecule. The synthetic cells have transmembrane DNA origami that are used to recognize and process intercellular signals. We demonstrate that multiple small vesicles aggregate onto a giant vesicle after a transduction of external DNA signals by an intracellular enzyme, and that the small vesicles dissociate when receiving ‘release’ signals.

We envision that this thesis will provide a new platform for building programmable synthetic protocells capable of chemical communication and coordination.