dally mutant ovarioles contain empty germaria. (A–A″) dally expression in the cap cells. dally enhancer-trap expression (dally-Gal4 UAS-GFP) is shown in green (A and A″). Cap cells are stained with anti–lamin C antibody (red; A′ and A″). (B and C) dally heterozygous (B) and homozygous (C) ovarioles stained with anti-Hts (red) and anti-Vas (green) antibodies. An empty germarium is marked by the white line. (D–E′) Dpp signaling in dally mutant germarium. Dpp signaling monitored by dad-lacZ expression (green) in dally heterozygous (D and D′) and homozygous (E and E′) germaria. Germline cells and the spectrosome/fusome are labeled with anti-Vas (blue) and anti-Hts (red) antibodies, respectively (see Materials and methods). In dally mutants, dad-lacZ signals were markedly decreased in 30% of the most anterior germ cells (asterisks). See also Fig. S1 B. Anterior is to the left. Bars, 10 µm.