The preferred term is “ribocomputing.” Take a molecule of RNA, the “messenger” chemical that carries instructions from a cell’s DNA to the rest of the cell, and basically rewire it. By hacking the RNA, it’s thus possible to take command of the processes of the cell, particularly that of protein synthesis. It’s also possible to rewire the RNA to respond to specific stimuli, offering an engineered microbiological system that reacts to inputs in the same way that an embedded computer might respond to a temperature sensor of accelerometer.
Synthetic biology or “hacked” biology is a quickly growing field, but the term ribocomputing is scarce, mostly limited to a single 2016 study. That was the case at least until this week and the publication of a paper in Nature describing RNA-based synthetic biological circuits that are capable of implementing just what I described above: sensing external signals and directing cellular machinery to respond to those signals in programmed ways. It’s fascinating but also a bit spooky.
Many efforts in synthetic biology involve compiling catalogs of biological “parts” that can be assembled into function bio-circuitry. These are consistent, modular building blocks that provide a basic Lego set for building biological machines. The downside of the modular approach, as explained in the current paper, is that the resulting circuits are complex and overly sensitive to their surrounding context. A cellular machine assembled in a test tube from prefab components is by nature a bit rickety. And, unfortunately, a living cell is a crowded, noisy environment.
Here, however, the machine’s parts are naturally a part of the cell. It’s just the RNA itself that’s rewired. This is done with help from what’s known as a Toehold switch. The switch is basically a small hairpin-shaped RNA nanostructure that gets inserted into a cell. The RNA of the switch is capable of inducing the cell to create a specific protein, but first it has to match with…