Journal: Nature Communications
Article Title: Ribozyme-enhanced single-stranded Ago2-processed interfering RNA triggers efficient gene silencing with fewer off-target effects
Figure Lengend Snippet: Cleavage at the 3′ end of the siRNA precursor by the HDV ribozyme enhances its expression and knockdown efficiency. ( a ) Secondary structure of saiRNA with HDV ribozyme at the 3′ end. The left part represents the saiRNA, with the guide sequence in red. The right part represents the HDV ribozyme. The blue arrow indicates the HDV ribozyme cleavage site. ( b ) Cleavage of the HDV ribozyme in vitro . The saiRNAs fused with a wild-type (saiRNA-RZ) or mutant (saiRNA-mRZ) HDV ribozyme at the 3′ end were transcribed in vitro by the T7 RNA polymerase. The transcripts were treated with T4 PNK without ATP and then analysed on a 20% denaturing polyacrylamide gel by ethidium bromide (EB) staining. ( c ) Schematic diagram of the shRNA and saiRNA with or without the HDV ribozyme (HDV-RZ) downstream of the 3′ end of the siRNA precursor. Expression of the siRNA precursors in mammalian cells was driven by an H1 promoter. The blue arrow indicates the cleavage site of HDV-RZ, and nucleotides marked in red represent the guide strand. ( d ) Knockdown efficiency and processing of shGP and saiGP transcribed by the H1 promoter as described in c . ( e , f ) Knockdown efficiency and processing of shRNA and saiRNA targeting the laminC (LC) and P53 genes in HEK293 cells. Luciferase and Northern blotting assays were performed as in d . Changes in protein levels on siRNA expression were determined by western blotting assays with antibodies recognizing laminC or p53. β-actin served as the loading control. ( g ) Effect of transfection dosages on the repression activity of shGP and saiGP-RZ. ( h ) Knockdown efficiency of the endogenous P53 gene by shRNA or saiRNA stably expressed in HEK293 cells transduced with lentiviral vectors. HEK293 cells were transduced with lentivirus encoding shp53, saip53 or saip53-RZ at different MOIs and selected by puromycin for 6 days. Expression of the P53 gene was measured by western blotting as in f . All the error bars represent the s.d. of three independent measurements.
Article Snippet: To measure the half-life of saiRNA with terminal 2′, 3′-cyclic phosphate or hydroxyl groups, T7-transcribed saiRNA-RZs treated or untreated with T4 PNK were incubated with Ago2-KO 293 cell lysates in RIPA buffer (50 mM Tris-HCl (pH 7.4), 150 mM NaCl, 1 mM EDTA, 0.5 mM dithiothreitol, 1% NP-40, 0.5% sodium deoxycholate (Sigma), 0.1 U μl−1 RNase Inhibitor and 1/100 protease inhibitor cocktail) for different time periods.
Techniques: Expressing, Sequencing, In Vitro, Mutagenesis, Staining, shRNA, Luciferase, Northern Blot, Western Blot, Transfection, Activity Assay, Stable Transfection, Transduction