It's the holy grail of synthetic biologists: creating a living cell from scratch. So far they’ve managed to make simple prototypes—essentially tiny fat balloons with a soup of genetic material inside, capable of reading genetic code, producing proteins, and transporting molecules around.
Yet these artificial blobs lack an essential feature shared by all living things: the ability to generate more copies of themselves.
Synthetic cells have mastered the art of stretching, a prerequisite for self-replication. Image credit: Rockefeller University
Self-replication is arguably the most sophisticated of biological phenomena and has long seemed nearly impossible to engineer. But clues are starting to emerge thanks in part to Albert J. Libchaber, the Detlev W. Bronk Professor Emeritus, who became interested in the process by which a cell deforms from a sphere into an oval—a first step required for it to split into two. “It’s not easy to divide a perfect sphere,” he says.
Together with Vincent Noireaux, a postdoc in the lab now at the University of Minnesota, Libchaber found a secret ingredient that can help cell prototypes elongate: polyethene glycol, a sticky molecule found in skin creams and soap bubbles.
Previously, the scientists had tried stretching their spherical creations with MreB, a protein that builds a bacterium’s inner scaffolding, which moulds the cell into its trademark rod-like shape. But MreB on its own did nothing to flatten Libchaber’s cell replicas; only after polyethene glycol was added did it turn into a dynamic polymer capable of inducing the sphere-to-oval transformation.
Source: Rockefeller University