Three types of dose-response-patterns caused by nonlinearities of the thermostatistical transcriptional machinery for promoters with two identical binding sites for one transcription factor .

The thermostatistical model of transcription initiation predicts different dose response patterns of gene expression that are caused merely by difference in the nonlinearity parameter of the thermostatistical transcriptional machinery. The patterns can be observed under conditions that can conveniently be expressed by means of the effective parameters and . ‘Single cross-over’ means a cross-over from a less-than-additive response to a greater-than-additive response when transcription factor concentrations are scaled up. ‘Re-entrant’ stands for a sequence of less-than-additive, greater-than-additive, and less-than-additive responses. Further parameters: and .