Part:BBa_K3332039

tetR

The tetR protein is able to repress pLtetO-1 promoter in the absence of ATc.

Usage and Biology

The tetR protein is used to inhibit pLtetO-1. It is part of the circuit designed to prevent engineered bacteria in the detection instrument from escaping.

Fig 1. Kill switch of the detection part.

pTrc-2 promoter is used to express mf-lon and MazF in the absence of ATc so as to inhibit the growth of E.coli. It is part of the circut designed to prevent engineered E.coli in the detection instrument from escaping.

In this circuit, LacI can repress pTrc-2 promoter and pTrc-2 derivative promoter ，while tetR can repress pLtetO-1 promoter. When ATc exits, it combines with 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, the expression of mazF often leads to the death of bacteria. So there comes the conclusion that the engineered E.coli won’t be killed by mazF as long as it is cultured in the environment with ATc. Therefore, when the E.coli escapes from our detection instrument, the effects can be reversed. That is to say, the E.coli will be killed by mazF. In the same way, we can see that mazF can be expressed and kill the E.coli in the presence of IPTG, MazF can be expressed and kill the E.coli.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

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