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Inferring gene regulatory networks using transcriptional profiles as dynamical attractors

Fig 2

Demonstration of the combinatorial Hill functions (A and B), and the regulation function (C and D) under the regulation of an activator and a repressor.

In the top two panels (A and B), two combinatorial Hill functions are plotted; in (A) two activators work independently to activate a target gene, while in (B), two repressors work synergistically. In the bottom two panels (C and D), the dependence of the regulatory function on the activating and repressing combinatorial Hill functions is plotted for two example cases. In (C), achieves the basal transcription rate fraction of 0.5 when there is a lack of both activator and repressor, or when both are present. Activation (resp. inhibition) occurs when the activator (resp. repressor) is abundant, and the repressor (resp. activator) is scarce. In (D), The Hill coefficient, k, determines the steepness of the regulation function; The basal expression level, f₀, controls the position of the middle plane and can slide between 0 and 1. The threshold T decides the TF abundance that will trigger the activation or repression.

doi: https://doi.org/10.1371/journal.pcbi.1010991.g002