Fig. 5

Concomitant maintenance of ductal sox9b expression with repression of endocrine differentiation by FGF and Notch signalling. (A, B) Expression at 3 dpf of sox9b with the endocrine marker neurod in wild type embryos treated from 54 to 72 hpf with DMSO (A) or with the FGF inhibitor SU5402 (B). Confocal planes containing the EPD are shown. (A2, B2) sox9b expression only is shown. (C, D) Ectopic Nkx6.1+ and endocrine Pax6 cells are found in the HPD of fgf10 mutants, as in sox9b mutants. Yellow dotted lines demarcate organ boundaries. (E–F2) 3-D rendering of the pancreas showing sox9b and neurod expression at 4 dpf at the level of the IPD in wild type embryos treated from 72 to 96 hpf with DMSO (E, E2) or with the Notch inhibitor DAPT (F, F2). (E2, F2) sox9b expression alone is shown. (G–G3) Detection of SOX9 protein in the Notch-responsive cells (PNCs) revealed with anti-mCherry in Tg(Tp1:hmgb1-mCherry) transgenic larvae at 5 dpf. (H) Quantitative RT-PCR analyses of sox9b and amylase expression in centroacinar and acinar cells isolated from the pancreas of adult Tg(Tp1:hmgb1-eGFP) (Tp1+) and Tg(ptf1a:eGFP) (ptf1a+) fish, respectively. EPD, extrapancreatic duct; HPD, hepatopancreatic ductal system; IPD, intrapancreatic duct. Scale bar=20 μm.