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Team:Groningen/project memory units
From 2011.igem.org
Memory Unit
As a memory units we are using bistable autoinducing loops that can be suppressed via a reversed promoter jammer. The Autoinducing loop plays a role as an amplifier of the input signal by regulating its own expression. To switch it off, we adopted the endogenous device from British Columbia 2009 team, which uses a reverse antisense promoter downstream of the coding sequence (https://2009.igem.org/Team:British_Columbia/Jammer).
Our implementation
In our implementation the first memory unit is based around a modified lambda Prm promoter(Bba_I12006) producing its own inducer cI. By means of the jammer it will be repressed in the presence of LasR. The second memory unit uses the lasB promoter(BBa_R0079) producing its own inducer LasR. This second loop can be repressed by arabinose via a reverse antisense arabinose-induced promoter. The transcription factor genes (cI and LasR) were fused in various combinations with different RBS's and degradation tags, resulting in 12 different construct variants. This was done to the expression rate and half-life that meets the criteria for bistable behavior best.
study the dynamics of the expression and half-life of different autoinducing loop components.
Results
TODO Firstly, we would like to test the leakage of promoter by cotransform autoinducing loop plasmid and reporter plasmid under control of appropriate promoter. Secondly, cotransformation assembled input and output systems with plasmid bearing various-variants of autoinducing loops would provide information about memory unit behaviour in time. Finally, integration of experimental data and our model would lead us to fine-tuned the expected system behaviour.
