Fig. 2.

Wg produced by escort cells is required for follicle formation. (A-F) Ovarioles in which Wg^RNAi is expressed in apical cells by Bab1-Gal4 (A,D), escort cells by 13C06 (B,E) or follicle cells by 109-30 (C,F) at 7 (A-C) or 21 (D-F) days after flies were shifted to 29°C to repress tub-Gal80^ts and promote Gal4 activity. Tissue is stained for Fas3 (red) and with DAPI (blue). Brackets indicate the extent of the germarium. Boxed regions in D-F are magnified in D′-F′ and schematized in D′-F′ (in the diagrams, cap cells are orange, germ cells are tan, escort cells are blue, and the FSC lineage is red). The asterisk in E′ indicates an apoptotic germ cell. (G) Quantification of follicle formation defects in ovarioles of each genotype. Ovarioles from 13C06, tub-Gal80^ts; TM2/+ flies were used as the control. Each data point is the mean of at least three replicates. Error bars represent s.d. ^*P<0.01 compared with control. Total n values are greater than 200 ovarioles for each data point. (H,I) Ovarioles from 13C06, tub-Gal80^ts; TM2/+ (control, H) or 13C06, tub-Gal80^ts; Wg^RNAi/+ (I) that were incubated with EdU for 2 hours, fixed, and stained for EdU (red) and with DAPI. (J) Quantification of the number of EdU⁺ follicle cells in ovarioles of each genotype. ^**P<0.001. Anterior is to the left. Scale bars: 25 μm in A-F; 5 μm in D′-F′,H,I.