Autogene Memory Circuit
Many synthetic biology applications depend upon the ability of cells to sense and respond to environmental stimuli. In designed organisms, this ability is often used to turn on the production of a predefined circuit through the detection of a specific compound (inducer). Once this original stimuli is removed though, the signaling pathway is no longer induced and over time the response is diminished. We are working on developing a memory circuit based upon positive feedback loops that would enable the cell to remember encountering an inducer and keep the downstream circuit turned on.
A long term goal of this project is to make multiple of these memory circuits within the same cell to allow for logic gating. The combination of stable memory and computational capacity could allow for timing-independent AND gating where both inducers don't need to be present at the same time. This could provide useful functions for biosensors deployed in the human gut where different stimuli, for example metabolic byproducts or inflammation markers related to food consumption, may be present hours apart from each other. Memory circuits are also useful in industrial bioproduction. Commonly used laboratory inducers, such as IPTG and arabinose, need to be constantly supplied in order to continually induce protein expression. Once scaled up to large volumes, the constant supply of these molecules can become costly and prohibitive. Having the ability to induce cells once and have them make a product until the circuit is turned off could provide cost savings.