Fig. 2

Effect of let-7b on the expression of caspase-3 and design of a molecular beacon (MB) for detecting let-7b. a Schematics showing the let-7b binding site in the 3′ UTR of human caspase-3. b Efficiency of let-7b transfection was measured by real-time PCR (*p <0.05). c Caspase-3 expression with or without let-7b transfection prior to H₂O₂ treatment was detected by western blotting (*p <0.05). d Let-7b targeting of caspase-3 was evaluated by a luciferase assay using luciferase vector containing the 3′ UTR of human caspase-3. HeLa cells were transfected with control vector or vector containing the 3′ UTR of human caspase-3 along with negative control miRNA (NC) or let-7b mimics (100 nM each) (*p <0.05). e Schematics showing the working principle of a MB designed to detect let-7b. f Working concentration of the MB was determined by an in-vitro assay using 100 nM let-7b and increasing concentrations of MB designed to detect let-7b. MB designed to detect miR-23 served as NC and denatured MB (Den MB) served as a positive control (*p <0.05). Quantitative data expressed as mean ± standard deviation of at least three independent experiments