Team:KULeuven/Project/Inverter

Components
The input signal for the InverTimer is filtered by using the T7 RNA polymerase promoter (BBa_I712074) and RiboLock3d (BBa_J23078). The InverTimer's output signal is the LuxI protein, encoded by BBa_C0061. The basis of the InverTimer system is the LacI repressor molecule, encoded by BBa_C0012, and the lac promotor (BBa_R0011).

Action
When there is a consistent input signal that can penetrate the Filter, LacI is produced from the T7 promoter with the adjacent RiboLock. This LacI (BBa_C0012) contains a C-terminal LVA tag for faster degradation and thus better responsiveness. LacI inhibits transcription from the lac promoter just downstream, acting as an inverter for the output LuxI signal. When no (or not enough, because of the filter) signal is present, the LacI repressor will not be made and LuxI will be produced. It is thus clear that when the filter system produces an input signal for the inverter, there will be repression of LuxI production. Otherwise, when no input signal from the filter system is present, LuxI will be produced.



When LuxI is present, it functions as a timer, slowly producing the quorum-sensing molecule 3OC6HSL from hexanoyl-ACP and SAM. 3OC6HSL has a very long lifetime if no quorum-quenching Lactonase is present and will accumulate. Not only inside the cell but it will also diffuse into the medium.

3OC6HSL is the bridge that links this InverTimer to the next device in our system, Cell Death. Our Reset device also impinges upon this small signaling molecule, making it a true crossroads in our total system.