Selected for speedy publication in the August 5, 2004 edition of Science Express, the study describes, for the first time, the ability to shut down a gene literally before it is born in the nucleus of a cell. The benefit over previous gene-silencing techniques is that the nuclear version may have the potential to last considerably longer than current methods that act in the cytoplasm, the cellular area outside the nucleus.
The new technique, and older gene-silencing methods that have given rise in recent years to a multi-million dollar pharmaceutical industry, utilizes ribonucleic acid (RNA), the cousin of DNA. Specifically, researchers use synthetic, short pieces of RNA called short interfering RNA (siRNA), to shut down genes. The synthetic versions are patterned after naturally occurring siRNA in the body that may act as a defense against gene sequences that come from viruses or other genetic parasites.
The study's senior author, David J. Looney, M.D., associate professor of medicine at UCSD and the VA San Diego Healthcare System, said the new technique provides a new tool for research investigation aimed at elucidating the effects of different genes, and has the potential to modify gene expression in disease, such as knocking out expression of genes required for tumor growth. He cautioned, however, that further studies are needed to prove the general applicability of this concept.