Fig. 6. Overexpression of dpp but not gbb completely represses bam transcription in the testis. The testes in A and B are labeled for FasIII (red), Hts (green) and DNA (blue), whereas the testes in C and D are labeled for GFP (green), Hts (red) and DAPI (blue). The hub cells are identified by FasIII staining (red) in A and B, and are highlighted by circles in C and D. (A) The tip of a dpp-overexpressing testis showing more hub cells and slightly more single germ cells with a spectrosome (arrows) two or three cells away from the hub cells. (B) The tip of a gbb-overexpressing testis showing a normal hub and normal germ cell development. (C) The tip of a dpp-overexpressing testis showing that late differentiated germ cells (a two-cell cluster indicated by an arrow; a 16-cell cluster indicated by an arrowhead) fail to express bam-GFP. (D) The tip of a gbb-overexpressing testis showing that bam-GFP expression in the two-cell clusters (arrows) is delayed but is expressed in late differentiated germ cells (arrowhead). All the images are shown at the same magnification. Scale bar: 10 µm.