Team:Imperial College London/Temporal Control
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Revision as of 23:01, 16 September 2009
Contents |
Introduction
In the E.ncapsulator, temporal control is an integral part of the design. The 3 modules can only perform their successfully in the system if they have a temporal mechanism triggering them in a sequential manner. We have achieved this using 3 types of control:
- Chemical induction: Starts protein drug production (Module1).
- Autoinduction: Starts Encapsulation (Module 2).
- Thermoinduction: Starts Genomic Deletion. (Module 3).
Chemical induction
From the Module 1 genetic circuit, in the absence of IPTG in the system, the LacI repressor inhibits production of the protein of interest. When IPTG is added in we start the production of the drug of interest:
[For more details of the system, click here- (bits of Charles' literature review), includes info on lac operon and how we have modified it]
Autoinduction
The CRP glucose repressible promoter triggers the encapuslation phase.
- When levels of glucose in the medium are high, encapsulation is repressed
- When the levels of glucose in the medium are lower than the threshold, encapsulation is induced.
Starting the encapsulation and maintaining expression of colanic acid requires energy in the form of carbon sources. Bacteria use up a primary source to grow and trigger encapsulation and a secondary source to maintain the system once the primary source is used up. This phenomenon of switching from a primary source to a secondary source is known as a diauxie.
Encapsulation is induced automatically at point where bacteria switch from the primary source to the secondary source. This is known as autoinduction.
[link to more details]
Thermoinduction
c