Team:Imperial College London/Drylab/Protein Production


Protein Production

Based on the module 1 genetic circuit, a LacI-IPTG inducible promoter is responsible for kickstarting the production of the drug.

  • In the absence of IPTG, LacI represses the production of the drug (Cellulase or PAH)
  • When IPTG is introduced, the LacI repressing pathway is “de-repressed”, and some output protein is produced.
II09 NoIPTG yesIPTG.jpg


Our goals

The modelling aims to provide an overview and better understanding of the M1 system’s function by:

  • Characterizing the system.
  • Modeling to account for several factors that may reduce/hinder the production of the protein drug such as:
    • Lac promoter leakiness
    • IPTG toxicity
    • Stability of output protein

This module is an integral part of the design, as large-scale commercialization of the drug of interest depends on finding the optimal conditions for protein production. We implemented a system of differential equations, having made some assumptions and predictions about how the system will behave.

  About the model assumptions and predictions!

The System

Genetic circuits can be simplified using ODEs. A good introduction to modelling of genetic circuits is provided in [3]. By clicking on the link below we can see how genetic circuits were implemented in this system.

  about the equations and what they mean!

Summary of simulation results

  • When we introduce IPTG into the system, it temporarily removes LacI from the system. Hence, during this period of time, we produce the drug of interest.
  • When the effects of IPTG wear off, the system returns to equilibrium.
  • The more IPTG we add in, the higher the amount of output protein.

II09 SIm main prot.jpg

  about the simulations!


NOTE: These will be better understood once the reader has gone through the details ("Learn More").

  • The greater the strength of the Lac promoter, the greater the repressive action of LacI prior IPTG induction.
  • The greater the Lac promoter leakiness (kleak) the greater the basal amount of expression of protein of interest, prior IPTG induction.
  • The greater the amount of IPTG introduced, the greater the production of protein of interest.
  • Here we assumed that the range of IPTG we have introduced is non-toxic for our cells. Growth curves will tell us whether IPTG does limit cell growth at the ranges we are interested in.


[1]Steven H. Strogatz (1994). Nonlinear dynamics and chaos: with applications to physics, biology chemistry and engineering. Addison Wesley. ISBN 0-201-54344-3
[2]3.Kuhlman T, Zhang Z, Saier MH Jr, & Hwa T (2007) Combinatorial transcriptional control of the lactose operon of Escherichia coli. - PNAS 104 (14) 6043-6048
[3]2.Alon, U (2006) An Introduction to Systems Biology: Design Principles of Biological Circuits - Chapman & Hall/Crc Mathematical and Computational Biology

Protein Production
Drug Kinetics Genome Deletion

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