Fig. 1

meis3 is expressed in the endoderm anterior to the developing islet. (A–C) 24 hpf zebrafish embryos labeled by double in situ hybridization (both probes detected in purple) for insulin (black arrows) together with meis1 (A), meis2 (B) or meis4 (C) reveal that these meis genes are not expressed in the anterior endoderm. Both meis1 and meis2 are expressed in the neural tube (white asterisks). (D, E) At 24 hpf, meis3 (purple stain; black arrow) is expressed in endoderm just anterior to the insulin-expressing islet (red stain; red arrow). (F–H) Expression of meis1, meis2 and meis4 cannot be detected in the gut at 48 hpf (embryos co-labeled for insulin expression [black arrow]; both probes detected in purple). (I) meis3 (purple stain; black arrow) is expressed adjacent to the insulin-expressing islet (red stain, red arrow) at 48 hpf. (J) At 48 hpf, pdx1 expression is seen in duodenal cells and putative duct progenitors as well as the islet (yellow outline). (K) shh (purple stain; black arrow) is expressed adjacent to the insulin-expressing islet (red stain; red arrow) at 48 hpf . Developmental stage is indicated at lower left, probes are indicated at lower right. Lateral views in panels A–D; dorsal views in panels E, H–K; ventrolateral views in panels F, G. Anterior is to the left in all panels.