Difference between revisions of "Part:BBa K3278002"

Revision as of 04:44, 20 October 2019

pDawn with modified tac promoter

pDawn is a blue light control system which can start the expression of target gene under the inducement of blue light. More information in BBa_K1075044 added by iGEM13_Bonn.

However, expression leakage and delay are the two main problems of pdawn system. Leakage refers to the expression of target protein without light. According to our measurement, samples strictly kept away from light still had significant expression of GFP after being cultured for one night. Therefore, we carefully studied the gene circuits of pdawn system [2] [3] and hypothesized that enhancing the strength of the promoter of YF1 may enhance the repression of protein expression in the dark, thus solving the leakage problem.

In this part, we use the modified tac promoter(abbreviated as mtac promoter) to substitute the lacIq promoter in front of YF1 and Fixk2, largely reducing the leakage while maintain reasonable expression under blue light.

pDawn with T7 promoter is abbreviated as T7c below. pDawn with tac promoter is abbreviated as tac below. pDawn with modified tac promoter is abbreviated as mtac below. pDawn with YF2 is abbreviated as YF2 below.

[Go for the protocol of characterization:https://2019.igem.org/Team:ShanghaiTech_China/LightControl]

To see more changes on pDawn, go to the websites below.
pDawn-mEGFP: https://parts.igem.org/Part:BBa_K3278000
pDawn with T7 promoter: https://parts.igem.org/Part:BBa_K3278001
pDawn with mtac promoter: https://parts.igem.org/Part:BBa_K3278002
pdawn with tac promoter: https://parts.igem.org/Part:BBa_K3278005
pDawn with YF2: https://parts.igem.org/Part:BBa_K3278006


References:
[1] From Dusk till Dawn: One-Plasmid Systems for Light-Regulated Gene Expression. Robert Ohlendorf1, Roee R. Vidavski, Avigdor Eldar, Keith Moffat, and Andreas Möglich. Journal of Molecular Biology, 2012, Vol.416, pp. 534-542.
[2] Design and Signaling Mechanism of Light-Regulated Histidine Kinases. Andreas Möglich, Rebecca A. Ayers and Keith Moffat. Biophysical Journal, 2009, Vol.96 (3), pp. 1433-1444.
[3] Oxygen-Regulated In Vitro Transcription of Rhizobium meliloti nifA and fixK Genes. JEAN-MARC REYRAT,' MICHEL DAVID,' CASIMIR BLONSKI,2 PIERRE BOISTARD,' AND JACQUES BATUT'*. Journal of Bacteriology, 1993, pp. 6867-6872. Sequence and Features