Part:BBa_K3098022

Promoter(regulated by cI and lacI)

This promoter, improved from the part BBa_R0051, has become lacI repressible and thus IPTG inducible with the doubled lacO gene (lacI binding site) after the previous promoter. This new promoter has two binding sites for cI and two binding site for lacI. Hence, this new promoter can be regulated by two signals simultaneously: only when IPTG+/cI-, the coding sequence behind this promoter can be transcribed , leading to more potential uses in the design of gene circuits.

Usage and Biology

This part can be used at a specific situation when the pathway needs to be controlled by two signals. Such as the binary oscillator we designed in our primary project. To start this Period of oscillation, this system need an additional signal.

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]

Result

We constructed the gene pathway of both pR with sfGFP as regulator and and pR+dlacO with sfGFP, which means we added two sequences of lacO behind the promoter pR.
We set pR with sf GFP as positive control and the empty vector as negative control. We induced one group of pR+lacO by IPTG and detected the fluorenscence intensity to measure the expression amount of sfGFP.

Fig. Fluorenscence intensity comparison between pR, induced pR+lacO and noninduced pR+lacO

We found that the pR+lacO had lower expression of sfGFP at first, which means the pR had been transformed into a weaker one. And when the induction time increased, the group induced by IPTG had obviously increased expression of sfGFP told us the promoter we rebuilt can be successfully induced.