Using RNAi to silence WT1, therefore, led to the discovery that WT1 is the first transcription factor shown to regulate the formations of these junctions, Wilkinson says. "It is a transcription factor that dictates both the formation of the testes in the embryo, and the function of the testes after birth."
Researchers worldwide have been trying to harness the power of RNAi since it was discovered in 1998. RNAi rocked the world of science because of the vast implications this natural cellular control system potentially offered medicine.
RNAi is used by cells in many life forms to identify viral RNA, which often enters a cell as a double strand. The organism's own RNA, however, leaves the nucleus of cells (where it was produced by DNA) as a single strand, to be decoded by ribosomes into the proteins that perform all the work of the cell. RNAi, therefore, recognizes the double strand of viral RNA as different, and sets in motion cell machinery that destroys the invading RNA. This involves cutting up the double-stranded RNA, separating it into single strands, and destroying other single-stranded RNA molecules that are complementary to those small RNA segments.
Scientists quickly realized that if they could produce a double-stranded RNA that mimics the RNA produced by a gene they wish to silence, RNAi would do the job for them. Producing the decoy "small RNAs" that trigger RNAi has become a fairly simple process, Wilkinson says, but the difficulty has been to use these matches only in specific tissues, and to figure out a way to make this "treatment" last. The work by the M. D. Anderson team has come up with a solution that solves both problems.
The technique they developed involves use of two different "modules" that can be swapped in and out of the backbone of a vector. One is a small stem lo
Source:University of Texas M. D. Anderson Cancer Center