Difference between revisions of "Part:BBa K3777015"

Latest revision as of 16:35, 21 October 2021

TetR-T7(tetO)-sfGFP

Basic biosensor device for tetracycline detection.

Usage and Biology
The genetic circuit was composed of a coding sequence of tetracycline repressor which was inserted into an expression vectors with a consitive promoter(BBa_J23114) and RBS(BBa_K3777030), as well as sfGFP(BBa_K2762017) under the control of T7 promoter (BBa_K3777006). The terminator we used were BBa_B0010 and BBa_M36305.(Fig 1)
When tet was absent, TetR would bind to the inducible promoter（PI）and prevent RNA polymerase from initiating transcription, thus repressing the expression of reporter gene. If tet was present, TetR would no longer able to bind to the promoter, resulting in the expression of reporter gene.
We expressed this circuit in the E. coli BL21(DE3) cells for tetracycline detection. Thus we could roughly deduce the concentration of the antibiotics in the sample according to the fluorescence intensity.
Fig.1 Schematic overview of the genetic circuit.
Results
To verify the functionality of the biosensor, we performed a plate-reader experiment and measured optical density and fluorescence intensity every hour. We observed a correlation between concentration of antibiotics in the sample and intensity of fluorescent signal.

The figure shows that our cuircuit can recognize different concentrations of tetracycline, and the fluorescence value was positively correlated with tetracycline concentration which proves that our part can Detect the concentration of tetracycline

Reference：Alam Khalid K,Tawiah Kwaku D,Lichte Matthew F,Porciani David,Burke Donald H. A Fluorescent Split Aptamer for Visualizing RNA-RNA Assembly In Vivo.[J]. ACS synthetic biology,2017,6(9)
Sequence and Features