Predicted domains of greater-than-additive and less-than-additive responses for two promoters studied by Joung et al. (1994) and Lee et al. (2010).

<p>For rescaled activator concentrations and corresponding to a point ‘above’ (‘below’) the hyperbolic lines the thermostatistical model predicts a greater-than-additive (less-than-additive) transcriptional response. Solid line: re-analysis of the study by Joung et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034439#pone.0034439-Joung2" target="_blank">[6]</a> of a engineered promoter regulated by the transcription factors and cI. Dashed line: re-analysis of the study by Lee et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034439#pone.0034439-Lee1" target="_blank">[9]</a> involving a promoter regulated by the transcription factors and .