Fig. 1.

Disruption of Lsd1 results in the formation of GSC-like tumors. (A) Illustration of a WT Drosophila germarium. The cap cells, which form the GSC niche, are located at the anterior tip of the germarium (dark blue). The fusome (yellow) changes from a predominantly round structure in GSCs to a highly branched structure in developing cysts. The ECs (red) line the anterior region of the germarium. (B and C) Germaria immunostained for Hts (green) and Vasa (red). (B) WT germaria contain two to three GSCs and five to seven cap cells. (C) Lsd1^ΔN mutants display an expanded number of GSC-like cells with single round fusomes. WT (D) and Lsd1^ΔN (E) homozygous germaria stained for phosphorylated histone H3 (red). Positive staining revealed that Lsd1 mutant GSC-like cells continue to divide. WT (F) and Lsd1^ΔN (G) mutant germaria stained using an antibody against activated Caspase 3 (red). Cells undergoing cell death are rarely observed in WT germaria, but cell death occurs in Lsd1 mutant samples. In all panels, DNA is labeled with DAPI (blue). (Scale bars, 10 μm.)