Fig. 1. Anterior somatic cells in the embryonic gonad appear to be the precursors of niche cells in larval and adult gonads. The lacZ staining (blue) of enhancer trap 3914 is specific to anterior somatic cells in embryonic gonad (A), to nascent terminal filament (TF) and cap cells in the late third instar larval ovary (B), as well as to terminal filament (TF), cap cells (CC), and inner germarial sheath cells (IGS) in the adult ovary (C). In the adult testis (D), 3914 is specifically expressed in hub cells (H), somatic cyst progenitor cells (SCP) and somatic cyst cells (SCC). All panels are oriented with the anterior side of the gonad up and the posterior side down. Pole cells in A are stained with the anti-Vasa antibody (brown). Note that germ cells in all panels, such as GSCs in the adult testis (D), are negative for lacZ staining. Scale bars: 10 µm.