Simple and rapid synthesis of siRNA derived from in vitro transcribed shRNA.

Temporal gene silencing in mammalian cells using small interfering RNA (siRNA) is an invaluable tool for mammalian genetics and is becoming established. However, systematic studies of siRNA such as large-scale target validations are limited due to the high cost of chemical synthesis of double-stranded RNAs. Here, we devise a simple, rapid, practical and cost-effective method for preparing active siRNA derived from short hairpin (sh) RNA which is transcribed from a single-stranded synthetic DNA template using T7 RNA polymerase. This method doesn't require any sequence-limitation in the selection of the target region of genes. We demonstrate efficient silencing of several genes by the transcribed siRNAs obtained by this method.