The 6-mCEPh-purine modification does not impact the passenger cleavage. (A) Four siRNA duplexes used in this set of experiments. They bore different nucleotides (A, U, 6-mCEPh-purine or G) at the 5′ end of the guide strand and 5-nitroindole at position 19 of the passenger strand. (B) Scheme of RISC assembly and passenger cleavage. The passenger was 3′ radiolabeled. (C) A representative result of the passenger cleavage assay. The upper and lower bands correspond to the full-length and cleaved passenger strand, respectively. (D) Quantification of the target cleavage assay. The graph shows the average ± SD from three independent experiments using the same set of reagents. The ANOVA P-values are given in an inset under the graph. The results of pairwise comparison on the effect of 6-mCEPh-purine compared to natural nucleotides are indicated by asterisks (*) P < 0.05, (**) P < 0.005, (***) P < 0.0005. The detailed results of statistical analyses are summarized in Supplemental Table 1.
