Fig. S6

Prostaglandin Pathway Genes are Patterned to Regulate Endoderm Specification (Related to Figure 5) (A,B) Expression of ep2a, cox2a at 10 hpf, and cox1a and pdgh at 12 hpf as visualized by double in situ hybridization with myod (brown). (C) Expression of ep2a in a whole mount embryo at 12 hpf (6 somites). (D) Magnified expression of ep2a (purple) and myod (brown) at 12 hpf (6 somites), showing that expression of ep2a spans 4 cells from the midline. Each asterisk marks an individual cell. (E) Representative photomicrographs of adult zebrafish livers 3 days post-resection (dpr). The liver is highlighted by a yellow dotted line, the resection site by a blue line, and the arrow indicates the amount of liver regrowth. PGE2 activity mediated by ep4a is both necessary and sufficient to enhance liver regeneration. (F) Liver regeneration quantified as Regenerative Index = [Remnant + Regenerate (arrow)] / [Remnant] of the regenerating inferior lobe at 3 dpr. (Data represented as mean ± SD; * significant vs. control, ** significant vs. dmPGE2 exposure, t-test, p < 0.01, n=3-10 for each condition). (G) Visualization of proliferating cells marked by Proliferating Cell Nuclear Antigen (PCNA) in histologic sections of adult liver regenerates following hepatectomy and exposure to various agents modulating PGE2 activity. Exposure to dmPGE2 augments cell proliferation, whereas Indo abrogates cell proliferation. Proliferating cells in intestinal crypts can be seen in the DMSO panel. Black bar = 100 µm.