The research team, led by Norbert Perrimon, systematically inhibited the function of around 1,000 Drosophila genes that are predicted to affect diverse cellular processes. They observed that 16% of the inhibited genes altered the form or structure of the cells in some way.
Genes that caused the same changes in the cells when inhibited are likely to work together in a complex or pathway. Clustering genes by their effects allowed the researchers to assign functions to about 50 previously uncharacterised genes. Author Buzz Baum says, "The most exciting thing for me is that now you can take a step back and look at the bigger picture. You can find out which genes act together to do something, so you begin to build up a system-wide understanding of how cells work. Genes work in a community to do something, not on their own. With big-scale experiments you can start to see the internal logic of the cell."
The screening method makes use of RNA interference (RNAi) - introducing double stranded RNA into cells, to interfere with the expression of specific genes. In order to scale up the procedure, which normally tests one gene at a time, the researchers plated out cells into 384-well dishes and then added double stranded RNA to each well. After three days, when the targeted gene should be inhibited, they stained the cells so that they could visualise both DNA and components of the cytoskeleton. They then photographed the cells using an automated microscope.
Two postdoctoral researchers, Baum and Amy Kiger, independently studied the thousands of photographs generated
Contact: Gemma Bradley