Figure 5

Efficient target gene silencing with reduced OAS1 induction and lower shRNA expression. Total RNA was isolated from IS-1 cells (CTRL) or IS-1 cells 4 days after transduction with U6PT, sh319 or sh321 vectors. After reverse transcription, cDNA was analysed for expression of PAI-2 (A) and OAS1 (B). Data were generated by QRT-PCR, each target gene was detected in triplicate, error bars represent the standard deviation of mean values. 1 ml or 0.1 ml of each lentiviral vector stock was used, hence the designations 1 and 0.1. Vector titres were approximately 10⁶ transducing units per ml resulting in a multiplicity of transduction of approximately 10 for 1 ml used or 1 for 0.1 ml used. In C, shRNA expression was detected in total cell RNAs using a modified RNase protection protocol. Total RNA was mixed with radiolabelled probes for hybridization and RNase protection. Samples were resolved on a 15 % Acrylamide/8M Urea/TBE gel and RNase protected probes detected by autoradiography. Lane 1 shows the Mir-16 probe without RNase digestion or target RNA, lane 2 is as lane 1 with RNase digestion and lane 3 as lane 2 with U6PT-transduced cell RNA as hybridization target. Lane 4 shows the sh3 probe without RNase digestion or target RNA, lane 5 as lane 4 with RNase digestion and lane 6 as lane 5 with U6PT-transduced cell RNA as hybridization target. In lane 7 sh321-transduced cell RNA was used as the hybridization target for the sh3 probe with RNase digestion, and lane 8 is as lane 7 except that cells were transduced with 10-fold less vector titre (sh321 1 and sh321 0.1). Known nucleotide lengths (Ntds.) for the probes and the protected Mir-16 endogenous RNA are marked.