Vesicular tubular-shaped particles transported from nurse cells to oocytes in Drosophila egg chambers

In Drosophila, the embryonic axes are specified during oogenesis by the asymmetric localization of certain mRNAs in the oocytes. In this process many of the mRNAs are synthesized in nurse cells and transported through cytoplasmic bridges called ring canals into the oocytes. However, the nature of the transporting particles and the route of their passage have not been not well defined. Here, I describe the ultrastructure of particles moving from nurse cells to oocytes. Immunoelectron microscopic observation with Mab27E7 monoclonal antibody revealed vesicular-tubular shaped (VTS) particles that appear to migrate to the cortical area and are then transported into the oocytes.