Fig. 7
Nonlethal caspase levels inhibit spontaneous emergence of migrating cells and PGC migration. a, b Delaminating/migrating cells spontaneously emerge in non-irradiated WDs (of the indicated genotypes) compromised for caspase activity. The pouch areas in the lower row (marked in green by the sal::CPV) are the corresponding magnifications of the WD regions marked in yellow squares in the upper row. Arrows indicate delaminating/migrating cells detected by virtue of their compact shape (intense Venus fluorescence; green) and MMP1 expression (red). The Z-axis projection in a corresponds to the dashed line region in the upper image. Scale bars, upper row 50 µm and lower row 20 µm. c Quantifications of the intense Venus and MMP1 double-positive cells in a. “Pouch” and “Notum” indicate the WD areas in which the cells were detected. The examined WD numbers (N) are indicated for each graph bar. Error bars indicate s.e.m. ***P < 0.001, two-tailed unpaired Student’s t test. d Some of the intense Venus and MMP1 double-positive cells in the non-irradiated dcp-1−/−; drice−/− double mutant WDs migrated away from the pouch (arrows; quantified in c). Scale bar, 20 µm. e The developmental migration of PGCs is affected by low increase in effector caspase levels. Stage 13 embryos overexpressing the full length dcp-1 and drice coding regions (zymogens) in PGCs using the nos-Gal4 driver (which drives both maternal and zygotic expressions). PGCs are marked by anti-Vasa antibody staining. Yellow arrowheads indicate PGCs that correctly migrated to the gonads. White arrows and asterisks indicate PGCs that failed to migrate properly in the first and second migration phases, respectively. f Quantification of the percentage of stage 13 embryos with migration defects in genotypes shown in e. The numbers of examined embryos (N) are indicated. Scale bar, 50μm. g A model of irradiation-induced cell migration and apoptosis in the WD epithelial tissue. The green area (pouch) indicates a subdomain that is severely compromised for effector caspase activity, whereas the gray areas indicate WT tissue
