Figure 1

Crossreactivity is evident between let-7 microRNA family inhibitors. (a) Sequences from miRBase http://www.mirbase.org/ of the nine let-7 family members studied in this experiment. The 'seed' region (nucleotides 2 to 8), is indicated by shading. Nucleotides at which other family members differ from let-7a are underlined and in bold. (b) The let-7a dual-luciferase reporter was co-transfected with the negative control (NC, an equal concentration of non-functional nucleic acid molecule) or inhibitors targeting let-7a, let-7b or let-7c. (c) let-7b dual-luciferase reporter was co-transfected with NC or inhibitors targeting let-7a, let-7b or let-7 c. (d) A let-7c dual-luciferase reporter was co-transfected with NC or inhibitors targeting let-7a, let-7b or let-7c. HeLa cells were co-transfected with reporters and inhibitors 1 day after plating into 96-well plates, 10,000 cells/well, in antibiotic-free media. Inhibitor concentrations ranged from 0.17 to 21 nM; plasmid concentrations were constant at 100 ng/well. Dual-luciferase ratios were measured 2 days post-transfection. Results shown are averages from triplicate wells, normalized to appropriate controls, then expressed as fold-inhibition relative to negative control. Error bars are ± 1SD (sample) of the original triplicate data, scaled for all subsequent calculations.