Skip to main content
. 1998 Jun 1;12(11):1705–1713. doi: 10.1101/gad.12.11.1705

Figure 1.

Figure 1

 Patterns of Shh and Ptc expression in endoderm and pancreas. Upper schematic shows transverse sections through gut endoderm (E) and adjacent tissues including notochord (N) at stage 11 (A–C). Endoderm without Shh expression is white, endoderm with Shh expression is blue. Lower schematic shows transverse sections through notochord (N), aorta (a), stomach (S), pancreas (P), and duodenal (d) endoderm and adjacent mesenchyme at stage 18–19 (D–G). (A) In situ hybridization with Shh probe of transverse section through prechordal endoderm at the extreme rostral end of the digestive tract. Shh expression in the floor plate of the neural tube is detected dorsal to endodermal (en) cells also expressing Shh. Note absence of notochord at this rostrocaudal level. (B) Shh expression in foregut endoderm rostral to the anterior intestinal portal. Shh expression is evident in floor plate cells and notochord (N), dorsal to endoderm expression. Note absence of dorsal endodermal Shh expression and the transition from columnar shape of ventral endodermal cells to squamous shape of dorsal midline endoderm. Paired dorsal aortas are marked “a”. (C) Midgut/hindgut Shh expression. Arrowheads point to two stripes of endodermal Shh expression. Endoderm medial and lateral to these Shh-expressing cells does not express detectable Shh. Floor plate and regressing Hensen’s node cells at this caudal level do not express detectable Shh at this stage. (D) Shh expression in stomach (S) endoderm and notochord (N) after aortas (a) fuse. Expression of Shh is evident in dorsal and ventral columnar epithelial cells. (E) Endodermal Shh expression in the pancreatic anlage. Endoderm in the nascent dorsal (arrowhead) and two ventral pancreatic buds (arrows) does not express Shh in contrast to strong expression in duodenal (d) endoderm between the buds and ventral common bile duct endoderm in the liver (L). (F) Sagittal section of dissected foregut revealing Shh expression anterior to the dorsal pancreas bud (arrowhead and dotted outline) in stomach and duodenal endoderm. Space adjacent to the dorsal pancreas bud is the lumen of the right omphalomesenteric vein. (G) Sagittal section revealing foregut expression of Ptc in mesenchyme adjacent to stomach and duodenal endoderm and in dorsal pancreas endoderm (arrowhead), but little detectable Ptc in dorsal pancreas mesenchyme (outlined by dashed line). (A–G) Dorsal is at the top. (F,G) Anterior is at left.