DNA sequence analysis identified 33 genes [1, 2, 3] encoding Rab proteins in Drosophila melanogaster. 23 of these are orthologues of vertebrate Rabs [1, 3, 4] and almost all give rise to only one protein isoform  Rabs control specific steps in intracellular lipid and protein traffic [5, 6, 7]. Hence, Rabs represent not only valuable identification marks for organelles [8, 9, 10, 11, 12] and membrane compartments [13, 14, 15, 16, 17], but serve as logical targets for manipulation of specific intracellular transport routes [18, 19, 20, 21].
We have established a genetic resource that allows systematic, direct and controlled access to the Rab machinery in Drosophila melanogaster. Using homologous recombination, we targeted all functional genomic rab loci, fusing an YFP4xMyc tag to the N-terminal end of each Rab protein. The resultant rab alleles are viable and do not show obvious phenotypes. The common YFP-tag enables systematic and quantitative Rab mRNA and protein detection in vivo, and available genetic knock-down tools directed against GFP efficiently reduce YFP-Rab protein levels.
We imaged all YFP-Rab proteins with subcellular resolution in larval Fat bodies, Salivary glands, Wing discs, CNS and adult Ovaries and Testes [24, 25]. These organs compromise over 20 different cell types and we used controlled vocabulary to annotate the acquired images, describing features such as tissue and cell type specific expression, morphology and subcellular localisation.
The open access FLYtRAB database provides direct access to CATMAID , a free online platform that enables the user to view and download all 3D image data from the FLYtRAB library. In addition, FLYtRAB enables users to search for annotation terms linked to stored image data.