Investigation of Drosophila fruitless neurons that express Dpr/DIP cell adhesion molecules

Drosophila reproductive behaviors are directed by fruitless neurons. A reanalysis of genomic studies shows that genes encoding dpr and DIP Immunoglobulin superfamily (IgSF) members are expressed in fru P1 neurons. We find that each fru P1 and dpr/DIP (fru P1 n dpr/DIP) overlapping expression pattern is similar in both sexes, but there are dimorphisms in neuronal morphology and cell number. Behavioral studies of fru P1 n dpr/DIP perturbation genotypes indicates that the mushroom body functions together with the lateral protocerebral complex to direct courtship behavior. A single-cell RNA-seq analysis of fru P1 neurons shows that many DIPs have high expression in a small set of neurons, whereas the dprs are often expressed in a larger set of neurons at intermediate levels, with a myriad of dpr/DIP expression combinations. Functionally, we find that perturbations of sex hierarchy genes and of DIP-e change the sex-specific morphologies of fru P1 n DIP-a neurons. Overall design: scRNA-seq using 10x Genomics CHROMIUM Single Cell 3' Solution V2 Chemistry of 48hr after puparium formation (APF) male Drosophila Central Nervous System (CNS) cells where fru P1-expressing cells were genetically labeled with GFP.