| |
Fig. 6. Tm4sf3 is required for acinar and stomach/duodenum development. (A,B) Expression of the general pancreas marker Ptf1a is normal in tm4sf3 morphants (n=7), but also reveals that the dorsal (dp) and ventral (vp) pancreatic buds have not fused. The liver position (L) has changed compared with normal and is present below the pancreatic buds in the region of the stomach/duodenum. (C,D) Expression of the liver marker Hex was normal (n=18). P, pancreas. (E,F) Expression of the stomach/duodenum marker frp5 was almost completely abolished (40/44). (G,H) Schematic highlighting the phenotype seen in Tm4sf3 knockdown embryos. The pancreas normally grows behind the duodenum, as illustrated by the darker shading in the wild-type gut. In tm4sf3 morphants, the dorsal and ventral pancreatic buds do not fuse. (I,J) The acinar cell marker elastase was substantially reduced or completely abolished in Tm4sf3 knockdown embryos (19/27 absent, 8/27 reduced). (K,L) Expression of the early acinar differentiation marker XPDIp was normal in the dorsal and ventral pancreatic buds in tm4sf3 morphants (n=42). (M,N) Insulin expression was normal in the dorsal pancreas in a little over half the cases (16/29). Interestingly, ectopic insulin expression was found in the ventral pancreatic bud in 45% of our samples (13/29). (O,P) No expression of glucagon or somatostatin was detected in the stomach/duodenum (n=8). At this stage, neither is yet expressed in the pancreas. (Q-V) Representative serial sections from an individual isolated NF42 whole gut that were previously stained for ptf1a expression. (W,X) Three-dimensional reconstruction of the samples based on all serial sections. Pancreas is blue, liver is pink, intestine is yellow and the gall bladder is green. |
