A gene-silencing strategy that's increasingly popular in the laboratory may wend its way into the medicine cabinet. Several research groups have reported successfully using the technique, known as RNA interference (RNAi), against viruses, including HIV, hepatitis C virus, and poliovirus.
RNAi is based on the discovery that adding short, double-stranded RNA molecules to a cell can turn off the gene that the RNA matches. When a gene makes the protein encoded in its DNA, it first generates a single-stranded form of RNA called messenger RNA. In RNAi, the added RNA interferes with this messenger RNA, interrupting the production of the corresponding protein.