|
Display additional annotations [+]
|
| |
Figure 5. Sfrp5 is required to establish a foregut epithelium. (A,B) Removal of the neural plate at stage 13 reveals the archenteron floor foregut endoderm in control embryos (A) is a flat epithelial sheet of cells, while in sfrp5-MO embryos (B) the cells round up and are loosely adherent. Embryos are oriented anterior down. (C–H) Confocal immunostaining of anti-β-catenin (C,F), anti-atypical-PKC (D,G), and anti-C-cadherin (E,H) in the foregut region of midsagittally bisected control (C–E) and sfrp5-MO-injected (F–H) embryos at stage 20 (anterior left, dorsal up). Nuclei are counterstained in green. Insets show a high magnification of the foregut surface cells. (I–T) Confocal immunostaining of aPKC (I–N) and β-catenin (O–T) in the foregut and hindgut surface of control and Sfrp5-depleted embryos (anterior left) at the indicated stages. (U–W) The schematic shows the regions of the foregut (blue box) and hindgut (yellow box) imaged in I–T. The red line indicates the regions of the foregut and hindgut surface that exhibit a polarized epithelium with basolateral β-catenin and apical aPKC. The loss of Sfrp5 results in a failure of the foregut epithelium, reduced cell adhesion and a loss of apical–basal polarity. (fgc) Foregut cavity; (ar) archenteron; (bc) blastocoel. |
|
Display additional annotations [+]
|
| |
Figure 7. Sfrp5 antagonizes endogenous Wnt11 signaling. (A) Reducing endogenous Wnt11 rescues Sfrp5-depleted embryos. Embryos were injected in the D1 anterior endoderm at the 32-cell stage with a wnt11-MO, sfrp5-MO, or both the wnt11-MO and the sfrp5-MO. At stage 18, the foregut epithelium was assayed by anti−β-catenin or aPKC immunostaining of bisected embryos and gene expression was examined by in situ hybridization. Injection of the wnt11-MO expanded hhex and reduced vent2 expression. Coinjection of the wnt11-MO and sfrp5-MO rescued both the epithelial integrity and the changes in gene expression observed with sfrp5-MO alone. (fgc) Foregut cavity. (B) A model of how Sfrp5 restricts both Wnt11/β-catenin and Wnt11/PCP activity to coordinate foregut specification and morphogenesis. |
