Ectopic expression of dally expands the area of undifferentiated cells in the female GSC niche. (A and B) bam-GFP expression (green) in ovaries from c587-Gal4/+ (A) and c587-Gal4/UAS-dally (B) pupae. Anti-Hts and anti-Vas staining are shown in red and blue, respectively. (C and D) bam-GFP expression in ovaries from c587-Gal4/+ (C) and c587-Gal4/UAS-dally (D) adult germaria. The same markers were used as in A and B. (E and E′) Dpp signaling was monitored by dad-lacZ expression (green) in a c587-Gal4/+ adult germarium. Anti-Hts antibody stains the fusome (red). Strong dad-lacZ signals are seen in GSCs at the anterior edge of the germarium. (F–G′) Two examples of c587-Gal4/UAS-dally adult germaria in which ectopic dally induced abnormal expression of dad-lacZ in the posterior (arrowheads). Ectopic dally resulted in massive accumulation of GSCs throughout the germarium, but strong dad-lacZ expression was observed in a limited number of these cells, most frequently in the posterior. Anterior is to the left. Bars, 10 µm.