Team:MIT toggle


Revision as of 01:54, 27 October 2010 by McCoCo (Talk | contribs)

bacterial toggle

A genetic switch or toggle follows the general form of two proteins that inhibit the others' transcription. Because of this arrangement, the toggle has two stable states -- on or off -- and can switch between the states with certain inputs. This pseudo-binary, reversible setup implies a simple but powerful control over a genetic system.

The Bacterial team focused on implementing and improving the Collins toggle, pTSMa. pTSMa switches on if the cell is exposed to UV, and switches off with the addition of IPTG. The ultimate goal was to use the toggle to fine-tune our control over the growth of our polymerizing phage M13. We created a biobrick that fluoresced red when exposed to UV light, or when the toggle was turned "on" to represent where phage would be produced when our modules are connected. As an intermediate in our project, we have managed to create what is essentially an improved bacterial camera capable of instantaneous photography.

We implemented part of the Collins toggle in our bacteria, improving upon previous iGEM bacterial cameras by shortening the exposure time from hours (UT-Austin 2005) to seconds. During our experiments, noticeable cell death in UV-exposed regions prompted development of an additional feature. Our bacterial circuit improves upon the Collins toggle in that the power of UV light required to switch the toggle is reduced, resulting in significantly more cells surviving the image capture process.