Fig. 3. Epidermal engulfment in the absence of cell death in H99 and p35-expressing embryos. (A-F) A series of time-lapse images of (A-C) a wild-type embryo and (D-F) a homozygous H99 embryo injected with VGAL: (A,D) 1/2 GBR, (B,E) 3/4 GBR and (C,F) full GBR. (G-I) A series of time-lapse images of a UAS-p35; UAS-cGFP embryo injected with caged GAL4VP16 and VGAL and exposed to whole-embryo photoactivation: (G) 1/2 GBR, (H) 3/4 GBR and (I) full GBR. The images in A-F are projections of four 3 µm optical sections; G-I are projections of three 3 µm optical sections. (J) Correlation between AO and VGAL signals. A histogram plotting the closest distance between VGAL and AO spots was measured within 30 minutes of the appearance of the VGAL signal, n=40 VGAL spots from 11 segments in two embryos. (K) Segmental distribution of VGAL spots within the lateral abdominal epidermis. A histogram showing the distribution of VGAL spots in the anterior, middle and posterior third of the abdominal segments in wild-type (solid bar), homozygous H99 (hatched bar) and whole-embryo photoactivated UAS-p35;UAS-cGFP (checkered bar) embryos. The number of embryos samples was as follows. wild-type, n=23 segments from six embryos; homozygous H99, n=29 segments from five embryos; UAS-P35;UAS-cGFP, n=37 segments from 13 embryos.