Figure 6.
Dia regulates cell shape and adhesion in the epidermis. (A) Late-stage 12: prd-Gal4>UAS-diaCA. diaCA-expression causes deepening of segmental grooves. Groove morphology is significantly different from DRhoGEF2-overexpressing grooves. Cells do not elongate their apical-basal axis. (B–G′) Stage 14: wg-Gal4>UAS-diaCA. (B) diaCA expression induces ectopic furrowing (arrowheads). (C–F) diaCA expression (red in C and E) results in accumulation of E-Cad (green in C and D′), Arm (green in E and F′), and F-actin (red) at AJs. (G and G′) diaCA-expressing cells enrich cortical myosin II (arrowheads in G, Sqh in green, HA in red in G′). (H) Stage 12: en-Gal4>UAS-diaCA. Cells expressing diaCA retain columnar shape. Groove founder cells do not elongate their apical-basal axis. Strong F-actin accumulation is detected apicolaterally (arrowhead) where AJs reside. (I–J′) prd-Gal4>UAS-diaCA. (I) Stage 14: Dia (green, F-actin in red) localizes to the apical tips of filopodia (arrowhead) in diaCA-expressing amnioserosa cells. (J and J′) Stage 14: diaCA-expressing cells (green) in the epidermis accumulate F-actin (red) and form filopodia (arrowhead). (K–L′) Stage 14: prd-Gal4>UAS-DRhoGEF2>UAS-diaCA embryos stained for F-actin (red), DRhoGEF2 (green), and HA (blue). (K and K′) Grooves are extremely deep. (L and L′). Cells take on a rounded shape, and they accumulate F-actin uniformly at the cell cortex. Filopodia are not seen. Bars, 5 μm.