Fig. 1. sec5^E10 mutant germlines display defects in membrane addition and egg chamber polarity. (A-C) Wild-type development of the ovariole. Membranes are marked with phalloidin (red), which binds to F-actin, and nuclei with Hoechst 33342 (blue). The oocyte (^*) and egg chamber stage are indicated. At stage 7 (B), the oocyte nucleus (^*) has moved to an anterior corner of the oocyte. At stage 10 (C), the oocyte has grown disproportionately to the nurse cells while its nucleus (^*) remains at the dorsal anterior corner. (D-F) Homozygous sec5^E10 germline clones. (D) Mutant egg chambers often fail to exit the germarium (^*). Those that do possess multi-nucleate cells, lacking phalloidin-labeling between nuclei (arrowhead) and possessing aggregated ring canals (arrow). (E) By stage 4 or 5, all ring canals are clumped together in the multi-nucleate chamber (arrow). (F) Clones arrest by stage 6. Ring canals are aggregated (arrow) and follicle cells begin to die. Wild-type (G) and sec5^E10 (H) egg chambers labeled with fluorescein-conjugated tomato lectin (green) and phalloidin (red). Wild-type (I) and sec5^E10 (J) egg chambers stained for Syntaxin (green) and phalloidin (red). (K,K') The oocyte (^*), labeled with antibodies to Dynein Heavy Chain (green), is incorrectly positioned in sec5^E10 germline clones. Wild-type egg chambers (L) and two z sections through one sec5^E10 egg chamber (M). E-cadherin (green) concentrates at the adherens junctions between follicle cells in both mutant and wild type. Polar cells (arrows), labeled by antibodies to FasIII (red), are located at the posterior of the egg chamber in wild type, but are mispositioned in sec5^E10 germline clones. All images are single z sections of confocal image stacks. Scale bars: 20 µm.