Difference between revisions of "Part:BBa K3332037"

Revision as of 10:07, 26 October 2020

LacI-ssrAtag(mf-lon)

The LacI protein tagged with ssrtag(mf-lon) is able to repress pTrc-2 promoter and pTrc-2 derivative promoter.We use it to repress pTrc2 promoter and pTrc2 derivative promoter.

Usage and Biology

LacI is a protein that can repress pTrc-2 and pTrc-2 derivative promoter in absence of IPTG. Especially, the part has ssrAtag(mf-lon), which means it can be degraded by mf-lon.

Fig.2 Circut

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. In addition, LacI with ssrAtag(mf-lon) which can be degraded by mf-lon can accelerate the death.

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

Sequence and Features