dFlpTag, a RMCE-based tool for simultaneous endogenous protein tagging and cell labeling in Drosophila.

Conditional protein tagging is a potent technique for elucidating protein expression patterns. The existing MiMIC and CRIMIC insertion collections in Drosophila genome offer a foundation for rapidly generating conditional protein tagging strains. In this study, we introduce dFlpTag, a new tool designed to create both constitutive and conditional protein tagging strains from MiMic or CRIMIC insertions. Moreover, dFlpTag enables co-labeling of the source cells of the protein of interest in a cell type-specific or sparse fashion. To demonstrate its utility, we generated strains for tagging the pre-synaptic protein Brp, the post-synaptic and polarity protein Dlg1, and the transmembrane protein Dpr12, thereby revealing their expression across multiple or a specific neuropil in the Drosophila central nervous system, individual synaptic boutons at the neuromuscular junction, and in large and small patches of epithelial cells within larval wing discs. We advocate for the straightforward application of this tool to tag thousands of genes that already possess MiMic or CRIMIC insertions within a coding intron.