REColi: Signal amplification and formattable bacterial memory by DNA edition.

We have designed a synthetic digital device inspired by electronic circuits called multiplexers. Its 3-bit memory allows saving and processing binary inputs in E. coli. Induced expression of serine recombinases, capable of specific DNA editing, enables construction of biological analogues of transistors - transcriptors - and their use as elementary memory units called SR-latches. The fourth, strobe signal resets the system to its original state. We have shown that the system could efficiently store data about previous contact with inducing sugars across hundreds of generations. This memory unit offers high sensitivity in inducer detection and signal amplification, allowing cheap induction or further development and use as a trace contaminants sensor. Eight possible output combinations, reported as RGB fluorescent proteins, may also turn out to be useful for complex coexpression research.