Faulty gene silencing by RNA interference
American geneticists warn that switching off specific genes by what is known as RNA interference can lead to false results.
In RNA interference, or RNAi for short, complementary pieces of RNA pair with the messenger RNA (mRNA) of a read gene, thereby inactivating it. With this naturally occurring process, genes can also be switched off artificially.
However, there was already evidence that the RNA sections composed of only about twenty nucleotides match hundreds of different mRNA strands and thus lead to undesirable results. To avoid these mismatches, the genetic engineers also used longer, double-stranded RNA molecules (dsRNAs) for interference.
Philip Beachy and his colleagues from the Howard Hughes Medical Institute in B altimore have now systematically investigated false shutdowns by RNAi in the fruit fly Drosophila. To do this, they chose the well-known signaling pathway of the so-called wingless genes, which plays an important role in embryonic development in both insects and vertebrates.
As it turned out, the RNA fragments mostly fished out the wrong binding partners. The result was no better when using dsRNAs either. The method suggested the existence of new genes involved in the signaling chain, which turned out to be misguided.
The researchers therefore warn that the results obtained by RNA interference should be treated with caution.