Express siRNA Directly

Express natural double-stranded siRNA constructs (as opposed to hairpin-type siRNA). The expression cassette is flanked by opposing H1 and U6 RNA Polymerase III promoters and T5 terminator sequences. Double-stranded siRNA templates are easier and less expensive to synthesize, easier to clone, and more stable during propagation. These features make this vector easy to use, cost-effective, but the silencing efficiency achieved with these types of vectors is usually less than with single-promoter vectors. Successfully cloned siRNA template oligonucleotides are transcribed in both directions.