Construction and Transfection of PCR Products Expressing siRNAs or shRNAs in Mammalian Cells

In mammalian cells, the RNA interence (RNAi) effect has been observed through expression of 21–23 base transcripts capable of forming duplexes, or via expression of short hairpin RNAs. Here, we describe a facile polymerase chain reaction (PCR)-based strategy for rapid synthesis and evaluation of small interfering RNAs (siRNA) expression units in mammalian cells. The siRNA expression constructs are constructed by PCR, and the PCR products are directly transfected into mammalian cells for functional testing. This method is fast and inexpensive, allowing several different siRNA gene candidates to be rapidly screened for efficacy.