Figure 1.

The UAS/Gal4 system. The UAS/GAL4 is the most used method in the fruit fly to ectopically express or knockdown a gene of interest in a tissue- or cell-specific manner. It involves two independent transgenic lines, which are based on the yeast transcriptional activator GAL4 and its high-affinity binding site, the upstream activating sequence (UAS). Crossing a tissue-specific GAL4 line to an effector line that carries the UAS fused to a gene of interest, progeny with both the GAL4 and UAS components express the gene of interest in an activator-specific manner. As in this study, such approach allows for silencing of the Ids gene by overexpressing an UAS- Ids-RNAi construct.