Part:BBa_K3332038

pTrc-2

A promoter derived from pTrc-2 promoter can be strongly repressed by LacI protein. Ptrc-2 promoter has one lac operator, which means that it has less LacI binding sites so that LacI has a weak inhibitory effect on it.

Usage and Biology

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 bacteria in the detection instrument from escaping. In this circuit, LacI can repress ptrc-2 promoter and ptrc-2 derived promoter while the LacI 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 derived 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 bacteria escape from our testing instrument, the effect can be reversed, that is to say, the bacteria 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.

Characterization

The agarose gel electrophoresis images are below:

Error creating thumbnail: Invalid thumbnail parameters Fig.2 pTrc-2_E0420_pSB1C3[BBa_K3332086] digested by XbaI and PstI.

Error creating thumbnail: Invalid thumbnail parameters Fig.3 pTrc-2 derivative_E0420_pUC57[BBa_K3332087] digested by EcoRI and PstI.

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]