Team:Grenoble/Projet/Design/toggle

From 2011.igem.org

Grenoble 2011, Mercuro-Coli iGEM


The Toggle Switch

The Toggle Switch allows our bacterial strain to switch between one of the two different behaviors (Receiver or Sender) depending on the predominant concentration in the external medium: IPTG or Hg.

We take into account two proteins repressing (LacI/MerR) each other's expression (pLac/pMerT). We create the fundaments of a toggle system that can switch when using two inducers in the medium: IPTG and Hg.

Initially, both genes, MerR and LacI, are expressed repressing each other promoters: pLac and pMerT.

On the plate where Hg concentration is the uppermost, this inducer will remove the repression exerted on pMerT promoter. So, the LacI proteins will be expressed and by repressing the promoter pLac, LacI proteins are shutting down the other pathway of the toggle.

Inversely, where IPTG concentration is the uppermost, the other pathway will be activated.

This toggle switch is one of our module of modelling. The simulation obtained with this model are compared to the experiment here.