To adapt RNAi for the study of gene function in mice, Thomas Rosenquist of Stony Brook University (rosenquist@pharm.sunysb.edu; tel: 631-444-8054) and Greg Hannon of Cold Spring Harbor Laboratory (hannon@cshl.edu; tel: 516-367-8889) used genetic engineering to create mouse embryonic stem cells in which RNAi was targeted to a particular gene. (As Hannon and his colleagues established in a previous study, silencing a gene of interest through RNAi can be efficiently achieved by engineering a second gene that encodes short hairpin RNA molecules corresponding to the gene of interest.)
These stem cells were injected into mouse embryos, and chimeric animals were born. Matings of these chimeric mice produced offspring that contained the genetically engineered RNAi-inducing gene in every cell of their bodies.
When Rosenquist, Hannon, and their colleagues examined tissues from the transgenic mice, they found that expression of the gene of interest was significantly reduced everywhere they looked (e.g. liver, heart, spleen). Such a reduction in gene expression is called a "gene knockdown" to distinguish it from traditional methods that involve "gene knockouts" or the complete deletion of a DNA segment from a chromosome.
One advantage of the RNAi-based gene knockdown strategy, shown in
this study to work in wh
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Contact: Peter Sherwood
sherwood@cshl.edu
516-367-6947
Cold Spring Harbor Laboratory
19-Jan-2003