Team:Georgia Tech

Currently, scientific endeavors are being pursued to engineer a synthetic quorum sensing system in E. Coli to express green fluorescent protein (GFP) in response to exogenous quorum sensing molecules. However, certain limitation exists as regards to the time required for the expression of GFP fluorescence. Anywhere from thirty minutes to two hours is necessary from the addition of the autoinducer until sufficient GFP can be transcribed, translated, accumulated, and detected, which for some synthetic biology applications may be unacceptable.

To this end, the goal of our experiment is to develop an alternative method to quickly visualize the response of E. coli to exogenous autoinducer by expressing the already present fusion proteins of GFP to the autoinducer receptor. Specifically, the C-terminus end of the GFP protein would be fused to one copy of the receptor gene which will be TraR from Agrobacterium tumefaciens, with the N-terminus end fused to a second copy of the same receptor. The GFP/receptor domain will get continuously transcribed and translated in the bacteria but it will not be able to fluoresce as the domains do not constitute a functional GFP protein. This will be brought about by the dimerization of the TraR receptor in the presence of autoinducers. This alternative method of inducing GFP expression is hypothesized to be efficient and quicker than the methods currently used as it bypasses the transcription and translation machinery of the cell while expressing the GFP.