Figure 7.

JAK-STAT signaling regulates GaSCs proliferation. (A) The cardia of a upd-Gal4 UAS-GFP fly was stained with anti-GFP (green), anti-Arm (red), and DAPI (blue). White arrows point to the F/M junction. (B) The cardia of upd-Gal4 UAS-GFP/ STAT92E-lacZ flies were stained with anti-GFP (green), anti-β-gal (red), and DAPI (blue). White arrows point to the upd-Gal4 UAS-GFP (green) and red arrow point to the STAT92E-lacZ (red). (C) Flies with the genotype Stat92E-GFP/+; Stat92E⁰⁶³⁴⁶/Stat92E^F were given food containing BrdU for five days, followed by a five day chase at the restricted temperature (29°C). The cardia was stained with anti-GFP (green), anti-BrdU (red), and DAPI (blue). (D,E) Flies with the genotype Stat92E-GFP/+; Act-Gal4/+; tub-Gal80^ts/UAS-upd were cultured at the restricted temperature (29°C) for four days. The cardia was stained with anti-GFP (green), anti-Ptc (red in D–E), and DAPI (blue). (F,G) Diagram showing behavior and regulation of GaSCs in Drosophila. (F) The slow proliferative GaSCs first give rise to the fast proliferative progenitors in both foregut and anterior midgut. The progenitors then migrate and differentiate into the terminally differentiated cell types in both crop and midgut. (G) Schematic diagram summarizing the functions of JAK-STAT, Wg, and Hh pathways in regulating GaSCs′ behaviors in Drosophila. Anterior is at the top in all panels. Scale bars: 10 µm (A, C–F); 5 µm (B).