(A,A’) Transverse section of 5 dpf larvae expressing TgBAC(cftr-RFP) to show Cftr-RFP localization and TgBAC(cftr:Gal4); Tg(UAS:GFP) to mark the cytosol of cftr expressing cells with GFP. Dashed white lines indicate the periphery of pancreas. Inset is 3× magnification of ductal cells. ib: intestinal bulb. (B,B’) Transverse section of a 21 dpf larvae demonstrating Cftr-RFP localization at the apical membrane of the pancreatic duct in conjunction with TgBAC(ptf1a-GFP) expressed in the acinar cells. Cftr is observed at or near the apical membrane marked with phalloidin. (C,C’) Transverse section of 3 month, adult pancreas indicating Cftr-GFP expression in pancreatic ducts throughout the pancreas. Dashed white lines indicate the periphery of the pancreas. Red dashed box indicates inset (D). (D,D’) Cftr-GFP is localized at or near the apical membrane of the pancreatic ducts, marked by phalloidin staining. Arrows indicate ductal expression of Cftr. Scale bars = 50 µm.