Figure 4
EM analysis reveals defective septate junctions in vari mutants. Epidermis (A-D, I) and tracheae (E-H) of stage 16 embryos. (A, E): variMD109/CyO-twi-GFP; (B, F): variMD109; (C, G): vari03953b/CyO-twi-GFP; (D, H): vari03953b; (I): wild-type. Adherens junctions (black arrowheads) and developing septate junctions (white arrows) can be distinguished in wild-type embryos. The inset in E shows the regularly aligned septa of pleated septate junctions between adjacent cells. Septate junctions are absent in homozygous variMD109 (B, F) and vari03953b(D, H) mutant embryos, while adherens junctions are well developed (black arrowheads).