Construction and Modelling of an Inducible Positive Feedback Loop Stably Integrated in a Mammalian Cell-Line

doi:10.1371/journal.pcbi.1002074

Construction and Modelling of an Inducible Positive Feedback Loop Stably Integrated in a Mammalian Cell-Line

Figure 6

Phase portrait of the PFL model.

The tTA-d2EYFP mRNA concentration (y axis) has been plotted against tTA protein concentration (x axis). Varying Doxycycline concentrations ( through ) were used to investigate the dependence of the two stable equilibria (“ON” and “OFF” in the graph) on the amplitude of the input. The shape and dimensions of the two basins of attraction (the set of initial conditions ending up in one of the two stable steady states) can be studied with the same technique: in this figure the grey shaded area represents the basin of attraction of the “OFF” equilibrium for Doxycycline = nM.

doi: https://doi.org/10.1371/journal.pcbi.1002074.g006