Executing gene circuits by cell-free transcription-translation into cell-sized compartments, such as liposomes, is one of the major bottom-up approaches to building minimal cells. The dynamic synthesis and proper self-assembly of macromolecular structures inside liposomes, the cytoskeleton in particular, stands as a central limitation to the development of cell analogs genetically programmed. In this work, we express the Escherichia coli gene mreB inside vesicles with bilayers made of lipid-polyethylene glycol (PEG). We demonstrate that two-dimensional molecular crowding, emulated by the PEG molecules at the lipid bilayer, is enough to promote the polymerization of the protein MreB at the inner membrane into a sturdy cytoskeleton capable of transforming spherical liposomes into elongated shapes, such as rod-like compartments. We quantitatively describe thismechanism with respect to the size of liposomes, lipid composition of the membrane, crowding at the membrane, and strength of MreB synthesis. So far unexplored, molecular crowding at the surface of synthetic cells emerges as an additional development with potential broad applications. The symmetry breaking observed could be an important step toward compartment self-reproduction.
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. This work is supported by the Human Frontier Science Program Grant RGP0037/2015.
© 2020 National Academy of Sciences. All rights reserved.
- Cell-free transcription-translation
- Molecular crowding
- MreB cytoskeleton
- Symmetry breaking
- Synthetic cell
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't