Team:PKU Beijing/Project/Output


Project > OR Gate and Output


The OR gate and output module is constructed as below: Salicylate promter is placed upstream of the PO promoter, the double promoter construct can act as an OR Gate, either PhiR73 or salicylate can activate the promoter.

fig1. OR Gate and Output

In Cambridge 2007 Amplifier project, the PhiR73 activator and the PO promoter is used to amplify signal from an inducible promoter.

fig2. Cambridge 2007 amplifier project
picture from Cambridge 2007 page

In order to make the transcription level from PO promoter similar to that of the sal promoter, the activator is designed to be on a lower copy plasmid than the reporter. This is also discussed in the second stage assembly section.


In order to test whether the OR Gate works, we constructed the following 2 strains of E.coli to test each of the two promoters.

PKU Test OR Gate 1.png
PKU Test OR Gate 2.png

The first strain is to test the PO promoter, which consists of an PhiR73 activator that can be induced by salicylate. The Second strain is to test the Salicylate promoter(after PO promoter is inserted in between the pSal and the Transcriptional Unit).

The result of the induction is shown right: Fig3 shows the result of the first strain induced by salicylate. Fig4 shows that of second strain, induced by salicylate.

OR Gate Sal.JPG
Fig4. OR Gate activated by Salicylate. In order to see whether the inserted PO has blocked the function of the salicylate inducible promoter, we use salicylate to induce the strain. Fluorescence is observed, which demonstrates that salicylate promoter works in the OR Gate.
Fig3. PO-GFP Gate activated by PhiR73 delta. We believe that if PO-GFP can be activated, there is no problem that it can be still activated when pSal is placed upstream of it.