Difference between revisions of "Part:BBa K3015008"

Latest revision as of 23:31, 21 October 2019

pTheo-RBS-T7-Term

This is BBa_K3015005 fused to the T7-Polymerase BBa_K3015006 to increase the expression of a gene under the control of a T7-Promotor when Theophylline is present.

Usage and Biology

In the presence of Theophylline the T7-Polymerase BBa_K3015006 can be produced and will then increase the expression of amilCP BBa_K592009 under the control of the T7-Promoter BBa_K3015012.

We could show that the part BBa_K3015008 works very well based on the positive signal due to the binding of an inducer to the aptamer, which can be easily seen with the naked eye. Our team took pictures of spun-down microtubes consisting of Escherichia coli (DH10B) strain induced under different concentrations of Theophylline and different incubation time.

The tested expression cassette consists of the following two constructs (see figure 1 and 2):

Figure 1: T7 Polymerase construct

Figure 1 shows our T7-Polymerase under the control of a Theophylline inducible riboswitch. If T7-Polymerase is beeing expressed in the cell it will bind to the T7-Promoter and expression of amilCP (see figure 2) takes place. The amount of expressed amilCP is proportional to the presence of T7-polymerase.


Figure 2: T7 promoter construct

For proving the functioning of the switch, we set up overnight cultures with the plasmid construct and induced them with different Theophylline concentrations. In addition to that, negative samples with the bacteria including our construct with no concentration of the toxin were added for the ability to check the leakiness of our promoter. In our pre-experiment two separate overnight cultures were incubated without Theophylline (left) and with 4mM Theophylline (right) see figure 3.


Figure 3: Overnight Cultures after 15 hours uninduced (left) and induced with 4mM Theophylline (right)

Sequence and Features