Fig. 3. Expression profile of the medullary zone and the PSC. (A-E) Marker expression in the medullary zone. Medullary zone cells are characterized by their expression of DE-cadherin (A, red), dome-gal4/UAS-GFP (B, green), upd3-gal4/UAS-GFP (C, green), the uncharacterized GFP fusion line ZCL2897 (D, green), and act5C-GFP (E, green). The cortical zone is marked by Lz staining (A, green; C, red) as well as by P1-antigen staining (E, red). (F-J) Markers expressed in the posterior signaling center (PSC) cells. PSC cells are marked by Ser-lacZ (F-I, red) and show high levels of expression of Dorothy-gal4/UAS-GFP (F, green), upd3-gal4/UAS-GFP (G, green), uncharacterized GFP-trap lines ZCL2375 (H, green), ZCL2856 (I, green) and ZCL0611 (J, green). In H and I, insets show only the GFP expression in the PSC regions indicated by the arrows. upd3-gal4/UAS-GFP (G) is expressed in only a subset of PSC cells. PC, pericardial cell. (K-O) Lack of expression of specific markers also defines the PSC. PSC cells are positively marked by Ser-lacZ (red) and characterized by absence of expression of Pvr (K, green; inset shows the PSC region without Ser-lacZ for clarity), dome-gal4/UAS-GFP (L, green), Cg-gal4/UAS-GFP (M, green), U-shaped (N, green) and Hemese (O, green). To-pro-3 (blue) marks nuclei.