Fig. 1. Expression of Grh in the amnioserosa perturbs the progression and outcome of dorsal closure. (A,B) Dorsal closure: a membrane-associated Myc-tag labels amnioserosa at the stages indicated (lateral view; c381::Gal4). Arrows mark the edge of the epidermal sheets. (C,F) Grh expression in wild-type (C) and AS^G332>grh (F) embryos (arrows indicate amnioserosa; stage 14, lateral view). (D,G) Phalloidin staining marks the cell outlines in dorsal view of wild-type (D) and AS^c381>grh (G) stage-15 embryos; zippering has commenced at the poles in control but not in AS^c381>grh embryos. Arrows mark the edge of the epidermal sheets. (E,H) Cuticles from hatching stage. AS^c381>grh embryos (H) have a dorsal hole (arrows) and internal organs are extruded (asterisk).