Fig. 4
Ventral bud forms from distinct populations of Notch-responsive progenitors and Ptf1a-expressing cells. ptf1a:eGFP; Tp1:hmgb1-mCherry embryo imaged by confocal microscopy at 33 hpf (A,B) and 37 hpf (C). Embryo is positioned at 45° (halfway between a left-side lateral view and a dorsal view) to best observe the pancreas. (A) Bright-field image of fish showing orientation; a, anterior; p, posterior; d, dorsal; v, ventral. Top left-hand side is hindbrain, bottom right-hand side is yolk and positions of the notochord (n), dorsal aorta (da) and intestine (i), are shown. (B,C) Merged fluorescent and bright-field images (single optic sections) at 33 (B) and 37 (C) hpf. Owing to transgenic markers, cells responding to Notch signaling are red (Notch reporter) and cells expressing ptf1a are green (Ptf1a). The lumen of the gut tube is indicated by a broken line and pancreatic Ptf1a expression is detected by green fluorescence (*). PNCs of the ventral bud are in red (arrowhead). (B′,C′) Rendered views of developing pancreas. Optical sections of GFP have been digitally cut away to reveal PNC core of ventral bud in C′. Scale bars: 100 μm. |