Immunohistochemistry of TG(zpu.1:EGFP)^df5 20-day-old transgenic larvae. (A) Transverse section at the level of the pectoral fin (F) showing the pronephros (P), mesenephros (M), muscle (Mu), and gut (G). Enlarged views of the (B) mesonephros and pronephros junction, (C) pronephros, and (D) muscle. Original magnifications × 100 (A), × 200 (B), and × 1000 (C-D). Arrows indicate positive cells.