OBJECTIVETo extend the use of vector-derived siRNA by generating multiple shRNAs in the same plasmid.

METHODSConstruct a vector that expresses shRNAs targeting on Ku70 and Ku80 in tandem. The gene silencing efficiency of each shRNA was verified previously. After identification by restriction digestion and DNA sequencing, the reconstructed plasmid, named psiRNAKus, was transfected into the human hepatoma cell line HepG2. The tandem-shRNA-induced silencing of targeted genes was determined by RT-PCR at RNA level and Western blot at protein level.

RESULTSThe shRNAs encoded by psiRNAKus down-regulated both the expression of Ku70 and Ku80.

CONCLUSIONThe vector-derived siRNA delivery system that allows multiple shRNA species to be expressed from the same vector may be of value in experimental and therapeutic applications.