Fig. 5. Ed is required for tube floor closure during appendage morphogenesis. (A) Stage 11 mosaic egg chamber (dorsal view) with a large ed mutant clone (lack of NM marker) that includes much of both appendage primordia. (A') Ed expression is detectable in the posterior non-mutant follicle cells (arrow), indicating that this egg chamber is of a stage at which Ed would be expressed in all follicle cells except the presumptive roof cells (see Fig. 3D). (A'') Anti-phosphotyrosine (p-Tyr) staining. The interface between the roof and floor cell domains is morphologically distinguishable but not smooth (arrow), and the posterior border of the roof cell domain (arrowhead) is not distinguishable. (B) Stage 12 egg chamber (dorsal view) with one wild-type (bottom) and one mutant (top, lack of NM marker) appendage primordium. (B',B'') Staining with fluorescently-labeled phalloidin, basal section (B'), apical confocal section (B''). The opening of the mutant tube appears wider (arrows). (C-C'') Diagram of a single appendage primordium at successive stages of tube formation. Both cross-section (left) and surface views (right; anterior towards the left, dorsal towards the top) are shown. The presumptive roof cells (light gray) are flanked anteriorly and medially by a single row of floor cells (dark gray). To emphasize the floor cell movements, roof cells are not delineated individually in the surface views. (D-I) Appendage primordia expressing the rho-lacZ floor cell marker. (D-F) Wild-type appendage primordia. (D) Primordium at onset of tube extension phase (floor cell domain aligned with oocyte/nurse cell margin). The floor cells have elongated and the apices nearest the `hinge' between the anterior and medial domains have met. (E) Tube extension phase (floor cell domain overlaps nurse cells). The tube floor is nearly fully closed. (F) A later stage than E. The tube floor is closed. (G-I) ed mutant primordia. (G) Same stage as D. The floor cell apices have not met. (H) Tube extension stage, comparable with E. The floor cell apices have not met; the tube floor remains open. (I) Later stage than H. The tube floor remains open. (J,J') Two sides of a single stage 14 egg chamber in which all follicle cells are mutant for ed. Autofluorescence and DAPI staining reveal the eggshell structure and nuclei of the follicular epithelium, respectively. The dorsal appendages are severely reduced (arrow).