RNA interference: Hitting the on switch

Researchers in San Francisco have findings that suggest a whole new side to RNA interference. Erika Check reports on their attempts to make a revolutionary field more revolutionary still.

"That looks perfect," murmurs Robert Place as he watches a smooth line trace across his monitor. "It never works this well."

Place, a molecular biologist at the Veterans Affairs Medical Center and University of California, San Francisco, is using a spectrophotometer to measure the purity of a series of samples. Every sample contains a tiny drop of micro RNA (miRNA), a type of genetic regulator that dampens gene expression — or so the story goes. The experiment Place is absorbed in is the last he must complete before he submits a publication that could upend that story. He and his colleague, Long-Cheng Li of the University of California, San Francisco, think they have found some miRNAs that boost, rather than silence, gene expression in cells.

Their work could shake the foundations of one of the hottest topics in biology — RNA interference — which studies how short pieces of RNA regulate the expression of genes. Place knows that his experiment will draw intense scrutiny from other researchers, and therefore it has to go perfectly. And as far as he can see, it has. His spectrophotometer displays a series of flawless curves, free of impurities; it looks as if he and his colleagues are finally seeing the pay-off after a three-year saga of frustration and exhilaration.