Fig. 1.
Drosophila life cycle and UAS-Gal4 system. A The Drosophila life cycle is approximately 10 days and can be divided into four stages: embryo, larva, pupa and adults. After mating, female adult flies lay eggs, becoming fertilized embryos. These develop into 1st instar larvae within a day. The 2nd and 3rd instar larval stages are accomplished after one more day each. The development of pupa takes between 2.5 and 3 days. Fully developed adults eclose after 3.5 to 4.5 days. B The UAS-Gal4 system is a widely used tool in Drosophila research and enables tissue/ cell type specific expression or repression of genes of interest. The Gal4 line contains the tissue-specific promoter followed by the yeast-transcription factor Gal4. The UAS line harbors the Upstream Activator Sequence (UAS) which is located before the DNA sequence of the gene of interest or the respective RNAi for repression purposes. Mating of the two lines will generate flies expressing the Gal4 transcription factor in the intended tissue or cells, which will bind to the UAS sequence enabling expression or repression of the gene of interest. C Body plan of Drosophila melanogaster illustrating the heart tube, the brain, the gut and the proventriculus as well as the fat body and the Malpighian tubules. Images were created with Biorender.com