Team:Paris/Transduction overview2 strategy
Our strategy: The Fec operon
Few ABC transporter such as FecABCD (iron transporter) are able to induce a response regardless of the tranlocation, due to the activity of FecA, moreover some mutant can also have a constitutive expression of FecABCD .
The plan would be to use FecA- mutant receiver and FecA+ mutant donor to transfert the constitutive FecA protein to the receiver. In this case the receiver will express the FecABCD operon without being induce by ferric citrate in the medium , and so we could place under the control of the Fec ABCD promoter, which is called pfec, the gene sequence encoding for the response. For the moment a response that would be easy to detect is the fluorescence of the RFP and the biobrick BBa-J61002 is the perfect candidate to test the system.
We also discovered that some fecR and fecI mutants can be use to amplify the signal because they have a constitutive activity. So we put under the control of pfec a FecR and FecI mutated. When they will be expressed, they will be activators of pfec and consequently of RFP. Normaly we would be able to obtain a increasing fluorescence.
problems : the message is unidirectionnal and unrepeatable. It would just be a proof of principle that a vesicle-mediated controlled communication is possible.
Our strategy: The trick TCS
We could ,with the help of Alfonso Jaramillo, design a synthetic PBP which could detect the substrate we choosed and activate a specific HK. The previous work done by Valencia in 2006 was to design vanilin-sensitive PBP and a network for a graduated response whereas we just need a proteic sensitive PBP and a binary type of response.
Even if the idea of creating a synthethic protein was very attractive, it would have been difficult to have concrete result in just 3 months.