Fig. 7.

GRN mechanistic and stochastic model. Our GRN model is composed of coupled piecewise deterministic Markov processes. In this example 2 genes are coupled. A gene i is represented by its promoter state (dashed box) which can switch randomly from ON to OFF, and OFF to ON, respectively at k_on,i and k_off,i mean rate. When promoter state is ON, mRNA molecules are continuously produced at a s_0,i rate. mRNA molecules are constantly degraded at a d_0,i rate. Proteins are constantly translated from mRNA at a s_1,i rate and degraded at a d_1,i rate. The interaction between a regulator gene j and a target gene i is defined by the dependence of k_on,i and k_off,i with respect to the protein level P_j of gene j and the interaction parameter θ_i,j. Likewise, a stimulus (yellow flash) can regulate a gene i by modulating its k_on,i and k_off,i switching rates with interaction parameter θ_i,0