Effect of internal 2′-OMe modifications on guide-strand incorporation, strand separation, asymmetry, and RISC-target interaction. (A) Cross-correlation amplitudes in the cytoplasm (solid bars) and nucleus (open bars) after 3 and 12 h of incubation for the indicated siRNAs (mean ± SE). (B) Target interaction levels with EGFP-RISC determined by FCCS in living cells. Cross-correlation measurements were performed 1, 2, or 3 h after microinjection. Data are represented as the mean ± SE; solid and open bars indicate measurements obtained in the cytoplasm and nucleus, respectively.