What is the UAS-Gal4 System?

The UAS-Gal4 system is at the heart of RNAi in fruit flies. For my project, I will be working with two fly lines: the UAS fly line and the Gal4 fly line. The UAS fly line contains the dsRNA that causes RNAi, but it is not active unless it's promoted. The Gal4 line is the promoter and will activate RNAi. The UAS fly line is similar to scissors, it is actually responsible for destroying the instruction manual (see the "What is RNAi?" page for more detail), while the hands are necessary in order to get the scissors to cut anything. So together, the hand and scissors or the UAS and Gal4 will exhibit RNAi knockdown of the gene in the offspring.