Fig. 5. Organization of SJs is altered in cont mutants. Ultrastructural analysis of the epidermal SJs in control heterozygous cont/GFP embryos (A,D), homozygous cont (B,E) and nrg¹/Y mutant embryos (C) at stage 15. Adherens junctions at the apical side are indicated with asterisks. In control cont/GFP embryos, SJ strands (arrows) are observed at the level of a convoluted intercellular junction in the apicolateral region (A). Alignments of a small stretch of septa (arrows) are occasionally seen in cont (B) and nrg (C) mutants, and are often very basal to adherens junctions in these mutant embryos. High-magnification views of SJ strands in control (D) and cont mutant (E) embryos show that mutant SJ strands are narrower compared with control SJs. Intramembranous structures display a scalloped appearance in the heterozygous (arrowheads in D) but not in the cont mutant, whereas spacing between septa is normal in cont mutant. Scale bar: 200 nm for A-C; 100 nm for D,E.