Artificial oscillators
Researchers have developed simple cell-free gene circuits that can emulate the behaviour of cellular gene networks.
Engineers often use simplified models to test their ideas. For example, engineers test small-scale models of new airplane designs in wind tunnels to see how easily air flows by them. This saves the engineers the time and expense of building a full-sized aircraft only to learn it has serious design flaws.
The interactions of genes and proteins within living cells can be incredibly complex, and working out how a particular network works can take months or years in living cells. To try to speed up and simplify the process, scientists are developing models that do not involve cells. These models replicate the chemistry inside of the cells and allow scientists to observe complex interactions between genes, proteins and other cellular components. Some scientists have recreated complex patterns of gene expression in these cell-free models, but these systems still take a long time to make. It is also not yet clear whether these models accurately depict what happens in living cells.
Now, Henrike Niederholtmeyer, Zachary Sun and colleagues have created a cell-free system that allows the interactions of a large network of genes to be examined in a single day — a process that would previously have taken weeks or months. To test the model, Niederholtmeyer, Sun and colleagues recreated how networks of genes in the bacterium Escherichia coli interact to form “oscillations”, which produce a regular rhythm of gene expression. When the cell-free oscillator networks were inserted into live E. coli cells, the oscillators continued to produce the same patterns of gene expression as they did outside the cells.
Overall, the experiments show that cell-free models can accurately reproduce, or emulate, the behavior of cellular networks. This work now opens the door for engineering ever more complex genetic networks in a cell-free system, which in turn will enable rapid prototyping and detailed characterization of complex biological reaction networks.
To find out more
Read the eLife research paper on which this eLife digest is based: “Rapid cell-free forward engineering of novel genetic ring oscillators” (October 2, 2015).
Read a commentary on this research paper: “Synthetic biology: How to make an oscillator”.
