Fig. 3. Apoptosis-dependent elimination of supernumerary A101⁺ cells. (A) A101/TM6 ovariole triple-stained with DAPI (A, a1), anti-ß-galactosidase antibodies (red, A',a2,a3) and TUNEL (green, a2). (a1-a3) Magnification of the boxed region in A, A'. Arrows point to the dying A101⁺/TUNEL⁺ cell. (B) Wild-type ovariole triple-stained with DAPI (B), anti-Fas III antibodies (red, B') and TUNEL (green, B'). Arrowheads point to early germarial region 2b/3 Fas III⁺ somatic cells undergoing apoptosis. (C,D) hsp-flp/+; +/SM6; Act>CD2>Gal4, UAS-GFP/TM6 (C) and hsp-flp/+; +/UAS-p35; Act>CD2>Gal4, UAS-GFP/+ (D) stage 5-6 egg chambers double-stained for DAPI (C,D) and anti-Fas III antibodies (C',D'). (C') In a wild-type egg chamber, Fas III is expressed at a basal level in follicular cells, but is strongly expressed in pairs of polar cells. Six anterior Fas III⁺ polar cells are present in D'. All follicular cells of the ovarioles in C and D exhibited GFP staining (data not shown). (E,E') UAS-p35/neu^P72-Gal4; UAS-Histone YFP/+ stage 6 egg chamber triple-stained with DAPI (E), anti-Fas III antibodies (red, E') and YFP (green, E'). Four Fas III⁺ polar cells are present posteriorly in E'. (F,F') UAS-p35/+; neu^P72-Gal4/rpr-lacZ egg chamber triple-stained with DAPI (F), anti-Fas III (red, F') and anti-ß-galactosidase (green, F') antibodies. Among the 4 Fas III⁺ cells present anteriorly (F', boxed area and close up in inset), 2 also exhibit reaper-lacZ expression (boxed area). FIII denotes Fas III and rpr denotes reaper-lacZ.