Two techniques for studying biological mechanisms within living cells have emerged as powerful tools with enormous potential: chemical genetics and RNA interference (RNAi).

Ulrike S. Eggert and colleagues from Harvard Medical School, US, compare and contrast these methods that could potentially gain widespread use in diagnostics and therapeutics.

Chemical genetics uses small molecules to probe biological processes directly. The technique works by inhibiting protein function, quickly and often reversibly, and the effects can be monitored by real time live imaging.

 RNAi is a revolutionary technique that has been widely used since its inception a decade ago. The method uses small RNA fragments to destroy mRNA in the cell and the protein coded by the mRNA is subsequently depleted. Monitoring levels of that particular protein reveals the system at work. Any protein with a known sequence can be targeted and, as Eggert says, 'With the availability of the human genome sequence and advances in RNAi technology, genome-wide RNAi screening is now possible in mammalian cells.'

Both of these emerging technologies have their respective advantages and disadvantages, said Eggert. She comments that the key to using them in the future may lie in combining the techniques, to enhance their complementary strengths and reveal new potentials.

Sophia Anderton