Dlp is required for the GSC niche in the male gonad. (A–D′) HS is required to form the male GSC niche. Testes from ttv heterozygous (A and A′) and homozygous (B–D′) third instar larvae stained with anti-FasIII (hub cells; red), anti-Vas (germ cells; blue), and anti-Bam (differentiating germ cells; green). (A″) Schematic diagram of the image shown in A. Hub cells, GSCs, Bam-negative differentiating germ cells, and Bam-expressing germ cells are shown in orange, blue, light blue, and green, respectively. (E and E′) Specific expression of Dlp in the hub cells. Adult testis stained with anti-Dlp and anti–E-Cad (hub cell marker). (F and F′) Expression of dally in the hub cells. A dally>GFP adult testis stained with anti-FasIII (hub cell). (G and G′) The male GSC niche in a dlp mutant. dlp heterozygous (G) and homozygous (G′) larval testes stained with anti-Hts (green) and anti–E-Cad (red) antibodies. Germ cells were labeled with anti-Vas antibody (blue). In the dlp mutant, the hub cells directly contact cysts that have a branched fusome (yellow arrowhead). Anterior is to the left. Bars, 10 µm.