Fig. 6

Defects of fuchi pRNAi embryos in demarcating a forming germ disc. A–H Reconstructions of confocal stacks showing wild-type (A, C, E, G) and fuchi pRNAi (B, D, F, H) embryos stained for fuchi (green, A–H) and Pt-hh (red, A, B, E, F) or Pt-fkh (red, C, D, G, H) transcripts, DNA (blue, A–H), and β-catenin (blue, A’–H’; not shown in A–H) at stage 4 (A–D) and early stage 5 (E–H). In A–D, F, H, and I, the embryonic side (Em) is to top, with the abembryonic (Ab) to bottom. In E and G, the embryonic side is viewed from the top. Optical sections show the presence of specific cells expressing fuchi at the embryonic pole (insets, C, D, G, H). The boxed areas in A–H are magnified in A’–H’, respectively. fuchi transcript was detectable even in cells on the abembryonic side of fuchi pRNAi embryos, although the signals were restricted to within the nuclei. Cells expressing Pt-hh and Pt-fkh transcripts at reduced levels were observed at regions corresponding to the germ-disc rim and nearby abembryonic region in fuchi pRNAi embryos at early stage 5, but these cells did not serve as rim cells demarcating a forming germ disc. I Reconstructions of confocal stacks showing a fuchi pRNAi embryo stained for fuchi transcript (green, I, I1’, I2’), DNA (blue, I, I1’, I2’), and β-catenin (red, I1’; blue, I2’) at late stage 5. I1’, I2’ High magnification of the boxed areas in I as indicated. I1″, I2″ Cross sections of the rectangular regions in I1’ and I2’. The cluster of CM cells were eventually internalized, but with few cells internalized in other regions. Note that the cells spread over the abembryonic side with epithelial integrity retained to a certain extent. Scale bars, 100 µm in A; 20 µm in A’, inset of C