Figure 6.

Control reporters reveal high abundance of non-specific (miRNA-independent) hits. (A) Heatmap depicting the concentration-dependent response of miRNA-sensitive and insensitive reporter pairs to 163 putative miRNA inhibitors. These reporters utilized the PGK promoter and BGH 3′ UTR. While mutated reporters (4xM) were transiently transfected to HeLa and 3T3 cells, bulged miRNA-sensitive reporters (4xB) were stably integrated. Note that while mutated reporters are generally less upregulated, they yield essentially the same heatmap pattern as the matched reporters with intact miRNA binding sites. The color scale values represent linear relative luciferase activity. (B) Heatmap depicting the concentration-dependent response of miRNA-sensitive (1xP) and insensitive (luciferase) reporters that utilized the SV40 promoter and SV40 3′ UTR.