Difference between revisions of "Part:BBa K3788017"

Revision as of 22:40, 20 October 2021

lexA-repressed promoter

This part is constituted from -35 and -10 boxes, the +& transcription site, a LexA box and the beggining of the CDS of caa. The LexA box is a sequence that allows the binding of a tetramere of LexA that represses the trascription of the caa-cal operon.

This repression can be stopped when the SOS response is activated, due to DNA damage that activate RecA production that induce LexA's depolymersation.

Role in natural environment

Induced by the SOS response (LexA dependent) upon DNA damages (UV, mitomycin…). This promoter allow the expression of the operon caa-cal. caa gene is coding for Colicin A (ColA) a toxin produced by E. coli strains, and active against other non-immune E.coli strains. E. coli have an imumnity protein coded by cai gene (-). cal gene is codding for a lysis protein, when this protein is produce ColA can be delivered in the extracellular medium after the E. coli cells lysis.

Experiment design

To characterize the caa-cal promoter, we made a transcriptionnal fusion between caa and GFP coding sequence (BBa_E0040) before of the timer-lysis device (BBa_K3788018) that we put in the Registry as BBa_K3788019. This construction, according to what is known from this system functionment, is supposed to express GFP in presence of mitomycinC, that induces the SOS response by damaging DNA.

With the construction BBa_K3788019 we could determine whether the promoter is well responding to SOS response induced by DNA damages by adding different concentrations of MytomicinC.

Sequence and Features