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Team:Caltech/TXTL
From 2014.igem.org
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| TX-TL is a cell-free transcription translation system that allows for inexpensive and rapid prototyping of biological circuits. This is desirable as the current method of prototyping and debugging circuits requires DNA parts to be cloned into cells, which can take a long time. With TX-TL, once all the DNA parts have been obtained, the circuit can be tested immediately, and so several circuit iterations can be tested in the time it takes to successfully clone even one circuit iteration into cells. Since TX-TL is an in vitro process, behavior of components such as promoters, ribosome binding sites, and terminators may behave differently than in vivo. Because of this discrepancy, it is necessary to characterize different promoter strengths in TX-TL. | |||||||||||||
We chose to characterize the strength of the Anderson family of constitutive promoters (Berkeley iGEM 2006) in TX-TL. We used biobrick parts J23100-J23118, with the exception of parts J23108, J23109, and J23111. The first figure shows the reported RFP fluorescence values measured in vivo by Anderson et al for different constitutive promoter constructs. The second figure shows the in vitro RFP fluorescence values measured for the same promoters. For ease of comparison, the x-axes on both figures are the same. 
As is evident from the data, the overall trend of relative promoter strengths in TX-TL seems to be fairly consistent with what was observed in vivo. The weaker constitutive promoters tended to have more fluctuations in relative promoter strengths, but because RFP fluorescence was relatively low for these promoters, some of the discrepancies may have been caused by noise in plate reader measurements. The only significant discrepancies in relative promoter strengths come from parts J23107 and J23118. |
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