Fig. 5

fuchi transcript expression in specific cells on the embryonic and abembryonic sides of early embryos. A–H Chromogenic WISH of wild-type embryos at indicated stages using fuchi probes (left), counterstained for DNA (right). A, B Opposite sides of the same embryo. Arrowhead indicates the signal. C–F Lateral view. The forming/formed germ disc (gd) is up. Arrowheads denote cells expressing fuchi at or near the germ-disc rim. G, H Forming germ band (gb) with expanding extraembryonic region (ex). Asterisks mark the embryonic pole, closed blastopore, or posterior pole. I–O Reconstruction of confocal stacks showing wild-type embryos fluorescently stained for fuchi (green) and DNA (blue) at 15 (I, J), 21 (K), 25 (L, M), 32 (N), and 38 (O) h AEL. Asterisks mark the embryonic pole or closed blastopore. I, J The same embryo from different directions. I’–M’, N1, N2, O2 High magnification of the boxed areas in I–O. Cell–cell junctions visualized by β-catenin staining are traced in I’–M’, and N2. I”–M”, N2’, O2’ Optical sections corresponding to the rectangular regions in I’–M’, N2, and O2. Arrowheads indicate fuchi-expressing cells that appear to be internalizing or internalized. N1’, O1 Optical sections corresponding to the lines in N and O. β-Catenin signals (red) are overlaid in I”, L”, N1’, and O1. β-Catenin concentrations mark the cumulus (cm). Fat arrows indicate fuchi expression in the future extraembryonic region. P, P’, Q, Q’ Simultaneous detection of fuchi (green) and Pt-hh (red) transcripts and DNA (blue) at or near the germ-disc rim at early (P, P’) and late (Q, Q’) stage 5. Arrowheads indicate cells expressing both fuchi and Pt-hh before internalization and cells expressing only fuchi after internalization. Em, embryonic side; Ab, abembryonic side. Scale bars, 100 µm in A, I–O; 20 µm in other panels