FIG. 8.

Adhesion and shapes of wild-type (WT) and bullwinkle (bwk) floor cells. Stage 12 egg chambers expressing the rhomboid-lacZ reporter. Anterior is to the upper left. A white line marks the dorsal midline. (A) Wild type. The orange arrow indicates the direction of tube elongation. A yellow line highlights the shape of a single floor cell. Red arrows indicate the direction in which cell shortening will occur at stage 13. (B) The floor cells in bwk mutant egg chambers migrate laterally rather than anteriorly. An arrowhead marks the site at which the basolateral region of two floor cells have separated from each other. This behavior puts tension on the roof cells, which expand their apices and widen the lumen. Modified from Dorman et al.³⁸