(A-F) Hs-bam testes stained with Vasa (red, germ cells); Armadillo (green, hub, *); 1B1 (green, fusomes); and DAPI (blue, nuclei). (A) Without heat-shocks, testes are indistinguishable from wild-type and contain GSCs (arrowhead) and CPCs (arrow); spermatogonial cysts and spermatocytes are positioned progressively further from the hub. (B-F) Increasing heat-shocks depletes GSCs, but spermatogonial cysts and Vasa-negative cells (arrows) remain. (G) The average number of GSCs/testis (± standard deviation) falls with increasing ectopic Bam expression. (H) The average number of GSCs, gonialblasts and 2-cell cysts/testis (± standard deviation) inversely correlates with the number of heat-shocks. (I-J) Testes stained with TUNEL labeling (green, apoptotic cells); DAPI (blue, nuclei); Fasciclin III (red, hub, *). TUNEL-positive GSCs were not detected in wild-type or Hs-bam testes after 5 heat-shocks; apoptotic spermatogonial cysts were observed as expected. Scale bars = 10μm.