C: qPCR validation to test different ERK signal durations. HEK293∆RAF1:ER cells were treated with 4OHT and U0126 for different periods of time to generate signal duration scenarios of 0.5 to 8 hours (cf. Fig EV1 C). mRNAs of IEGs EGR1 and FOS relay signal duration to response duration, whereas ILGs CLU and FOSL1 decode signal duration to response amplitude (qPCR data for all 17 validated mRNAs is shown in Fig EV6 A). 