Fig. 1.

Fig. 1. Ductal heterogeneity in the adult zebrafish pancreas.

(A) Uniform Manifold Approximation and Projection (UMAP) plot showing the different cell clusters. The classifications were based on known marker genes highly expressed in each cell type in the zebrafish pancreas. The two clusters of pancreatic ductal cell types are denoted by dashed lines and arrows. NK, natural killer. (B and C) Feature plot shown in UMAP embedding of selected ductal markers (B), Notch and BMP downstream genes enriched in pancreatic ducts, and novel ductal markers (C). (D) Immunostaining using a Vasnb antibody in Tg(tp1:EGFP) transgenic larva showing the ducts in the hepatopancreatic biliary system. The dashed lines outline the organs in different colors, i.e., pancreas (yellow), gallbladder (magenta), liver (cyan), and intestine (white). Scale bars, 200 μm. (E to G) Representative confocal images of immunostaining of Cdh17 and Cldnc in Tg(tp1:EGFP) larvae (E) and (F) and in situ hybridization for anxa4 in Tg(tp1:EGFP) larvae (G) with Z-projection (E′) and (E″), (F′) and (F″), and (G′). The pancreas (yellow), islet (cyan), and non–Notch responsive ducts (white) were outlined by dashed lines in different colors. The Notch-responsive intrapancreatic ducts are indicated by arrows (orange). Scale bars, 200 and 40 μm (magnification). (H) Double transgenic for tp1:EGFP and tp1:H2BmCherry with anti-Vasnb staining showing the labeling pattern in the duct and islets in the larvae pancreas. The pancreata, extrapancreatic duct, intermediate duct, and islet are highlighted with yellow, cyan, white, and orange dashed lines, respectively. Scale bars, 200 μm (left) and 40 μm (right). A, anterior; P, posterior; D, dorsal; V, ventral. (I) In situ hybridization for krt4 showing the extrapancreatic-to-intermediate duct system with bifurcation in 6 dpf larva. The insets are magnified Z-projections with white dashed lines outlining the tree-like structure of the intermediate duct. Scale bars, 200 and 40 μm (insets).