Fig. 3. Accumulation of DE-Cad in yan mutant border cells. The expression of Fas3 and DE-Cad was compared between yan/+ (WT) and yan mutant clones (see Materials and methods for details). (A-D') Actin is visualized by Alexa-568-phalloidin (red). (A-D) Expression of GFP (blue) marks non-mutant cells in stage 9 mosaic mutant egg chambers. (A'-D') yan⁴⁴³ mutant follicle cell clones are marked by the absence of GFP (blue). (A,A') Slbo is expressed both in yan mutant and non-mutant BCs. (B,B') The polar cell marker Fas3 is restricted to polar cells, even when outer BCs lack Yan expression. (C,C') DE-Cad accumulates in yan⁴⁴³ mutant BCs at the boundaries between outer BCs and polar cells (asterisk), as well as at the interface between BCs and squamous follicle cells (arrow). (D,D') Mutant BCs accumulate high levels of DE-Cad on their surface (arrows) and connect non-mutant BCs and the follicular epithelium. Asterisks mark polar cells.