Fig. 2. Differentiation results in death of zpg cells. (A,B) Ovaries stained with anti-Vasa to mark the germ line (green) and anti-phospho-Histone H3 to mark mitotic cells (red). Mitotic cells at the GSC position can be observed in both wild-type (A) and zpg (B) ovaries. (C,D) Flies carrying a hs-bam transgene were heat-shocked, and their ovaries dissected and stained with anti-Vasa to mark the germ line (green), and with the mAb 1B1 antibody to mark the cell cortex, fusomes and spectrosomes (red). hs-bam, zpg heterozygous mutant ovaries showed a series of egg chambers attached to empty germaria (C). hs-bam, zpg homozygous mutant ovaries lacked germ line (D). Control ovaries of heat-shocked zpg mutants showed the zpg phenotype (D, inset). Scale bar: in A, 20 µm for A,B; in C, 50 µm for C,D.