Figure 3

sds22 is required to maintain epithelial cell shape and polarity in follicle cells. (A-C)sds22 mutant clones induced in the follicular epithelium of Drosophila egg chambers with hs.Flp and marked by the absence of GFP. (A) An sds22 mutant clone showing altered cell shape. Cells have shortened along their apico-basal axes. Phalloidin (red) marks the filamentous actin cytoskeleton, which can be seen to be slightly weaker along lateral cell membranes within the mutant clone. DAPI (blue) marks nuclei. (B) An sds22 mutant clone showing both altered cell shapes and cells beginning to round up and form a double layer. Phalloidin (red) marks cell outlines. DAPI (blue) marks nuclei. (C) An sds22 mutant clone showing multi-layering of mutant cells, indicating loss of apico-basal polarity. Phalloidin (red) marks cell outlines. DAPI (blue) marks nuclei. (D-F) UAS.sds22-IR and GFP expressing clones stained for anti-aPKC (apical marker, blue) and anti-Dlg or anti-α-Spectrin 3A9 (both baso-lateral markers, red). (D) Small UAS.sds22-IR and GFP expressing clone showing spreading of basolateral marker (Dlg, red) around the plasma membrane. Mutant cells have a rounded appearance. Note, only one mutant cell is a polar cell, identified by strong aPKC staining (blue). Other mutant cells (e.g.: arrowhead) show reduced or diffuce aPKC staining. (E) Larger UAS.sds22-IR and GFP expressing clone showing spreading of basolateral marker (anti-α-Spectrin 3A9, red) around the plasma membrane, indicating a failure to maintain apical-basal polarity. aPKC staining (blue) remains largely apical in this clone. Arrow points to the absence of anti-α-Spectrin 3A9 staining in wild-type apical membranes. (F) A very large UAS.sds22-IR and GFP expressing clone showing spreading of the basolateral maker (Dlg, red) around the plasma membrane. The cells form a double layer. aPKC staining (blue) appears abnormally reduced or diffuse.