Fig. 3. Defects in oogenesis resulting from overexpression of wild-type Pav-KLP. Live (A,B,D), Hoechst-stained (C) or immunostained (E-H) egg chambers expressing GFP-Pav-KLP (green) are shown. DNA is shown in red (E-H) and Staufen in blue (G-H). (A) Stage 5 oocyte with GFP-Pav-KLP in speckles within nurse cell nuclei (arrow); GFP-Pav-KLP is also present in ring canals (arrowhead). The oocyte nucleus appears to contain a filamentous network (dashed box and arrowhead in inset). (B) An egg chamber in which the oocyte nucleus (small arrowhead) is being pushed towards the posterior pole by an invading nurse cell (small arrow), which has been able to pass the nurse cell/oocyte border (large arrow). The large arrowhead points at one of the four ring canals that are normally located at the nurse cell/oocyte border. (C) Egg chamber in which the oocyte at the posterior half has been invaded by three nurse cell nuclei (arrowheads). (D) Dumpless egg chambers with nurse cells that have retained most of their cytoplasm (arrowhead). Although dorsal appendage follicle cells have migrated more or less normally, the appendages (revealed by auto-fluorescence) are broad and irregular in shape (arrow). (E,F) Egg chambers isolated from females fed for 24 hours on unsupplemented yeast paste (E) or yeast paste containing 1 mg/ml colchicine (F). Egg chambers isolated from untreated females contain nurse cells that have a clearly visible nuclear GFP-Pav-KLP network (arrow in E). A similar network is also associated with the oocyte nucleus (arrowhead in E). In colchicine-treated egg chambers GFP-Pav-KLP is still present in nurse cell nuclei, but it does not form filaments any more (arrow in F). The network associated with the oocyte nucleus has also collapsed (arrowhead in F). (G) Overexpression of GFP-Pav-KLP can lead to egg chambers, in which the oocyte (arrow) fails to localise to the posterior pole (asterisk). (H) An egg chamber in which one nurse cell (arrow) has passed the nurse cell/oocyte border without affecting Staufen localisation at the posterior pole of the oocyte (arrowhead). Bars, 20 µm (A), 50 µm (C,E-H), 100 µm (B) and 200 µm (D).

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