The Tale behind the Discovery
In 1997 the Fire-Mello team found that by specially designing RNA with two strands they could silence targeted genes. The singled-stranded RNA molecule of messenger RNA, also known as "sense" RNA, conveys information from a DNA template to the machinery that "turns on," or expresses, a specific gene. The Fire-Mello RNA molecule has two strands similar to the famous double-helix structure of the related molecule DNA. One strand of the double-stranded RNA molecule is sense RNA, with a structural sequence that is the same as the nucleotide sequence in the target gene. The other strand, known as "antisense" RNA, has a complementary sequence to that in the target gene. When the double-stranded molecule is introduced into an organism, it interferes with the message-carrying process and shuts down the gene.
RNAi also exists naturally as a defensive mechanism in cells. Since its discovery it has become a powerful tool to understand developmental processes, and it is now commonly used to investigate gene function. Using RNAi, scientists now routinely "knock out" specific genes to prevent their expression, observe the disruptions to normal processes, and thereby help determine what the gene does. The method also opens up the possibility of treating various types of diseases by either shutting down the disease-causing gene or by directing researchers to appropriate pathways for developing new drugs. The Fire-Mello discovery was recently patented and has been widely licensed in the U.S., Europe, and Japan to address a broad range of research questions. Science magazine identified RNAi as a "Breakthrough of the Year" in its December 2002 issue.
As with many scientific discoveries, the research that led to the discovery of RNAi started out w
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Contact: Tina McDowell
tmcdowell@ciw.edu
202-939-1120
Carnegie Institution
2-Oct-2006