fgf24 is required for the specification of the ventral pancreatic bud. (A) General morphology of a MO fgf24-injected embryo at 3 dpf compared with a control injected embryo. Identical results were obtained with mutants and morphants and illustration in morphants or mutants is stated on the images. (B) trypsin (try) and ceruloplasmin (cp) expression in fgf24 loss-of-function embryos at 3 dpf. trypsin was reduced in 80% (n=121) of embryos, whereas cp was not affected. (C) Expression of the ventral bud marker ptf1a and of the pancreatic LPM marker isl1, or of the gut marker gata6 and the pancreatic LPM gene meis3 at 36 hpf. ptf1a was absent in 32% and reduced in 59% of the embryos (n=146). isl1 was absent in 17% or reduced in 80% (n=81) of embryos, and meis3 was reduced in 72% (n=95). The orange arrows indicate expression in the pancreatic LPM. (D) fgf10 and fgf24 expression at 36 hpf in the pancreatic region in fgf24 loss-of-function embryos. fgf24 was repressed in the pancreatic LPM in 52% of the embryos (n=96). (E) ptf1a (green arrowheads) was expressed at 50 hpf in both control and the fgf24 loss-of-function embryos. DB, dorsal pancreatic bud; FB, pectoral fin buds; VB, ventral pancreatic bud.
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