Difference between revisions of "Part:BBa K3332037"

Revision as of 10:11, 26 October 2020

LacI-ssrAtag(mf-lon)

The LacI protein tagged with ssrAtag(mf-lon) is able to repress pTrc-2 promoter and pTrc-2 derivative promoter.We use it to repress pTrc-2 promoter and pTrc-2 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 pLtetO-1 promoter. When ATc exits, it can combine tetR, so that pLtetO-1 promoter can’t be repressed. Then LacI which is controlled by pLtetO-1 can repress 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 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 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