Border cell migration in the Drosophila ovary is an ideal system for studying cell migration in vivo. These somatic cells delaminate from the epithelium that surrounds the germline and migrate through the nurse cells of the ovary to the anterior end of the oocyte. Three signalling pathways are probably involved: ecdysone, acting through its receptor Taiman (Tai),possibly regulates the timing of border cell migration; while PVF1 (a VEGF/PDGF receptor ligand) and Gurken (an EGF receptor ligand), possibly act as guidance cues. In a screen for genes involved in this process (see ), McDonald et al. identified Pvf1, and tested its ability, and that of other factors including Gurken, to guide border cells to new targets – only PVF1 was able to do so. Both Tai and PVF1 were found to regulate E-cadherin localization in border cells, possibly accounting for the interaction between these pathways.
