Model and gene regulatory network of the parameter estimation challenge. A. Example of a case of regulation of the transcription of coding sequence g4 by proteins p1 and p4, respectively activator and repressor, through the activator (as4, green box) and repressor (rs2, red box) sites. The rate of production of g4 is given by the transcription dependent on the promoter pro4. The rate of production of p4 is given by the translation dependent on the ribosomal binding site rbs4. B. Gene network from model 1 of the Parameter Prediction challenge consisting of 9 genes whose 45 parameters and the prediction of response to perturbations were requested from challenge participants.