Researchers at Cold Spring Harbor Laboratory have successfully co-opted a natural cellular mechanism to shut down the activity of specific genes in mammalian cells cheaply and efficiently. The new technique should speed the exploration of gene function for many research and clinical applications, and may eventually be used in gene therapy to selectively kill cancer cells, to block HIV infection, and for several other purposes (for figure, see accompanying PDF).
"There hasn't been a tool this sharp in a long time," says Doug Conklin who, along with Greg Hannon, led the Cold Spring Harbor research team.
The new technique is published in the April 15 issue of Genes and Development. It stems from work in several laboratories, including a discovery made four years ago by Andy Fire of the Carnegie Institute of Washington and Craig Mello of the University of Massachusetts. These scientists found that they could block the expression of a gene in nematode worms by injecting the animals with double stranded RNA corresponding to the gene, or even by simply feeding the animals the double stranded RNA. (Genes are made of DNA. RNA is a chemical cousin of DNA, but has different structure and properties).
Such blockage of gene expression by double stranded RNA was termed "RNA interference"RNAi, for short. RNAi is now known to operate in humans, mice and other mammals, as well as in fungi, flies, and plants. An early incarnation of the phenomenon was uncovered in 1990 by a horticultural researcher who, when trying to create more purple petunias, achieved an unexpected opposite result (i.e. more white petunias!).
"RNAi took the worm world by storm," says Hannon. Moreover,
scientists quickly realized that such a deceptively simple and effective
way to block individual genes migh
Contact: Peter Sherwood
Cold Spring Harbor Laboratory