B: Response amplitude for all simulated combinations of mRNA half-life and transcriptional delay. Response amplitude is shown over time (columns) and in respect to input function (rows). For sustained signalling, all primary response genes exceed their half maximum response amplitude. Pulse and transient signalling inputs are only sufficient for immediate-early genes and short-lived delayed early genes. Long-lived mRNAs with half-lives greater 120 minutes require sustained signalling inputs to exceed their half maximum response amplitude. Example parameter sets displayed in (A) are marked with asterisk in (B). Dashed lines indicate cluster borders: IEG: Immediate-early genes, t1/2 ≤ 120min and ∆t ≤ 30min. ILG: Immediate late genes, t1/2 > 120min and ∆t ≤ 30min. DEG: Delayed early genes, ∆t > 30min. 