Cells have sophisticated backup systems in place to handle scenarios when things go wrong. In particular, there are redundant genes in place to handle situations when problems occur. As pointed out in the article, this failsafe operation presents a problem for traditional and simplistic knock out schemes which are used to understand gene function. However, help is on the way in the form of a new screening technique.
"In a typical RNAi screen, researchers begin with a library of short interfering RNAs (siRNAs) targeting specific genes. Each siRNA disrupts the gene's ability to produce a particular protein. Scientists place the siRNAs on thousands of cells, with just one gene being targeted in each well of cells. Then they watch the cells and record changes.But this approach fails to capture some key players because many genes are redundant. Thus, cells can mask their distress when they lose a single gene by turning to fail-safes with the same function. Perrimon's approach overcomes this obstacle.
"If you take one part out of a plane engine, it still works, but if you take out that part plus its fail-safe, then you're in trouble," explains corresponding author Chris Bakal, a postdoctoral research in the Perrimon lab."
