In organisms as diverse as nematodes, trypanosomes, plants, and fungi, double-stranded RNA triggers the destruction of homologous mRNAs, a phenomenon known as RNA interference. RNA interference begins with the transformation of the double-stranded RNA into small RNAs that then guide a protein nuclease to destroy their mRNA targets.

RNA interference (RNAi) is a powerful tool in deciphering gene function. It has been used extensively, especially in cultured mammalian cells. We have shown that RNAi-induced gene silencing can be generated in mice. With conventional transgenic techniques, shRNA-expressing constructs can be introduced into one-cell mouse embryos. The transgenic animals so obtained exhibit reduced expression of ...