SUBCELLULAR-LOCALIZATION OF THE SEGMENT POLARITY PROTEIN PATCHED SUGGESTS AN INTERACTION WITH THE WINGLESS RECEPTION COMPLEX IN DROSOPHILA EMBRYOS

The product of the segment polarity gene patched is a transmembrane pr otein involved in the cell communication processes that establish pola rity within theembryonic segments of Drosophila. Monoclonal antibodies have been raised against the patched protein, and by immunoelectron m icroscopy part of the patched staining is found associated with discre te regions of the lateral plasma membrane of the embryonic epidermal c ells. Using a mutation affecting endocytosis (shibire) we find that pa tched is a membrane-bound protein, which is internalized by endocytosi s, and that the preferential sites of accumulation resemble the descri bed localizations of the cell-cell adhesive junctions of the epidermal cells. patched partially co-localizes with the wingless protein in the wingless-expressing and nearby cells, in structures that seem to be e ndocytic vesicles. These data suggest the interaction of patched prote in with elements of thereception complex of wingless, as a way to cont rol the wingless expression.