Fig. 1.

A siRNA synthesized from DNA template in vivo inhibited expression of transfected gene. (A) Strategy for generating siRNA from DNA template in vivo under the control of U6 promoter. The individual motif is 19-nt long and corresponds to the coding region of the gene of interest. The two motifs that form the inverted repeats are separated by a 9 bp. The transcriptional terminational signal of five thymidines (T) is added at the 3′ end of the inverted repeat. The resulting siRNA is predicted to fold back to form a hairpin dsRNA as shown (drawing not to scale). (B) Expression of chimeric SPAG9-GFP fusion protein in COS-1 cells. Fluorescence microscopy of COS-1 cells transfected with SPAG9-GFP: expression of chimeric GFP (the green) fused with SPAG9 (the red) in the same cell. The green and red fluorescence images were merged using Image Pro-Plus, version 5.1. DAPI for nuclear staining. (C) Inhibitory effect of gfp siRNA on SPAG9-GFP expression in COS-1 (original magnification 1000×). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this paper.)