Figure 1.

Mean downregulation is correlated with target abundance. (A) Schematic of the hypothesis that target abundance determines mean downregulation of individual targets. Micro/siRNAs with many targets downregulate their targets to a lesser extent than micro/siRNAs with few targets. (B) Expected correlation between target abundance and log expression ratio. This can also be considered an anti-correlation between downregulation and target abundance. (C, D) Differential downregulation by miR-155 and miR-128, where miR-155 targets are more downregulated than the targets for miR-128. (E) Predicted target concentration and mean log expression ratio across 146 micro/siRNA transfection experiments in HeLa cells. (F) Predicted target concentration and mean downregulation across 21 independently measured, single time point microRNA transfection experiments. Curves were fit to log(1−a/(x−b)), where a and b were determined by least squares error.