Difference between revisions of "Part:BBa K3332036"

Revision as of 09:40, 26 October 2020

RBS1

The ribosome binding site which has suitable strength for the kill switch in detection part. We use it to favor TetR expression in the absence of aTc.

Usage and Biology

RBS1 is used to favor tetR expression in the absence of ATc. It is part of the circut designed to prevent engineered E.coli in the detection instrument from escaping. Its strength fits the design of this monostable switch.

In this circuit, LacI can repress ptrc-2 promoter and pTrc-2 derivative promoter ，while the tetR can repress the pLtetO-1 promoter. When the ATc exits, it can combine tetR, so that the pLtetO-1 promoter can’t be repressed. Then the LacI which is controlled by the pLtetO-1 can repress the pTrc-2 promoter and pTrc-2 derivative promoter. As a result, mf-lon and MazF can’t be expressed.

As a kind of bacterial toxin, MazF can cause the bacteria death. So there comes the conclusion that as long as the engineered E.coli are cultured in the environment with ATc, it won’t be killed by the mazF, but when the E.coli escape from our testing instrument, the effect can be reversed, that is to say, the E.coli will be killed by the MazF. In the same way, we can conclude that in the presence of IPTG, MazF can be expressed to cause bacterial death.

Fig.1 Circuit.

Sequence and Features

Reference

[1] Chan CT, Lee JW, Cameron DE, Bashor CJ, Collins JJ. 'Deadman' and 'Passcode' microbial kill switches for bacterial containment. Nat Chem Biol. 2016;12(2):82-86. doi:10.1038/nchembio.1979