Team:Hamburg/Modeling/Networks

Genetic toggle switch for PezT expression

Our GroEL-PezT biobrick shall enable heat-inducible cell lysis. Conducting heat induction would release our miRNA2911 production which was triggered by light before. One major problem here is an activation of the GroEL promotor and thus PezT caused cell lysis at normal temperature (some kind of leakiness); therefore not reaching sufficient miRNA product. To stabilise our cell lysis event, we can employ a gene regulatory network called the genetic toggle switch [1]. It consists of a double negative feedback loop leading to a bistability network with memory function. This means the following:

  • the network can only attain two possible steady states (concentrations of all components): PezT-expression-state versus no-PezT-expression state
  • when one of the two possible steady states is once reached, this network state is naturally stable (memory function)
  • each state is induced by certain, different sets of start conditions
  • it is possible to switch the network state, when using inductor molecules (IPTG, cIts)

The construction of the network can be seen below in the figure. The repressors lacI and clts conduct the double negative feedback, and can theirselves be inactivated through IPTG and heat respectively. The bistability arises from the fact that either lacI or clts, but never both at the same time, can have a high concentration, and each of them promotes its own production.

DLE analysis

  1. SimRNA: a coarse-grained method for RNA folding simulations and 3D structure prediction. Michał J. Boniecki, Grzegorz Łach, Konrad Tomala, Wayne Dawson, Paweł Łukasz, Tomasz Sołtysiński, Kristian M. Rother, and Janusz M. Bujnicki. (to be published).
  2. Humphrey, W., Dalke, A. and Schulten, K., "VMD - Visual Molecular Dynamics", J. Molec. Graphics, 1996, vol. 14, pp. 33-38.


We thank our sponsors: