Composite

Part:BBa_K3777024

Designed by: SiYuan Peng   Group: iGEM21_OUC-China   (2021-10-01)


KB2-tetR-T7(tetO)-3WJdB-Ptet-sgRNA

A biosensor device for better tetracycline detection.

Usage and Biology
Compared to our another part TetR-tetM-T7(tetO)-3WJdB(BBa_K3777014),it adds a binding site which can be regonized by dcas9 proteins and sgRNA.(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. But KB2 will bind to 3WJDB leading to lower fluorescent .
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. 799px-KB2-tetR-T7%28tetO%29-3WJdB-Ptet-sgRNA.PNG
Fig.1 Schematic overview of the genetic circuit. 800px-T--OUC-China--result--V.png
Verifying the strand replacement reaction. Promoter J23104 is much stronger than J23110. TetR-T7(tetO)-3WJdB has no KB2, so it is set as a negative control.
The result of this experiment proved that it’s valid to repress the fluorescence in vivo, which strongly support the feasibility of the ‘improved circuit’.

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 Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    INCOMPATIBLE WITH RFC[12]
    Illegal NheI site found at 260
    Illegal NheI site found at 283
    Illegal NheI site found at 1262
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal XhoI site found at 121
    Illegal XhoI site found at 1388
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]


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Categories
Parameters
None