Figure 7.

(a) 2-Thiouridine (s²U) structure, R = β-D-ribofuranoside residue. (b) Sequences of the P10 and P10-thio modified siRNAs. (c) Comparison of the relative (EGFP/RFP) fluorescence in HeLa cells transfected with reporter plasmids: pEGFP-Wt-PSEN1(400) or pEGFP-Mut-PSEN1(400), pDsRed-N1 and siRNA: P10 and P10-thio (1 nM). Dotted lines represent the antisense strands of the used siRNAs. Positions of the C-C mismatch between the guide strand of siRNA and the wild-type PSEN1 mRNA are indicated by the black dots. Red dot represents the site of the s²U modification at the antisense strand. The level of the relative EGFP/RFP fluorescence in cells transfected with control nonsilencing siRNA was used as 100%. Statistical analysis of differences between two groups of data (Wt-PSEN1 versus Mut-PSEN1) were calculated by the use the Student's t-test (for data with normal distribution) or by the nonparametric Mann-Whitney's U-test. The differences with P < .05 were considered as statistically significant.