Fig. 8. At bud stage, lens and pituitary precursor cells do not upregulate ptc1 in response to shh mRNA. (A-D) Bud stage embryos labeled with probes for (A,B) hgg1 (red) and ptc1 (black), (C,D) dlx3b (red) and ptc1 (black). (E) At the 18-somite stage, dnPKA mRNA and rhodamine-biotin injected, transplanted cells are ptc1 positive (arrowheads) in ectoderm of eye vesicle in unlabeled host (n=11). (F) At prim-5 stage, transplanted cells (rho, red) contribute to lens (n=27). (A-D) Dorsal view of prospective head region, ventral towards the top. (E) Dorsal view, anterior towards the top, midline towards the right. (F) Side view, anterior towards the left, dorsal towards the top; confocal fluorescence micrograph reconstructed from 90 optical sections (optical slice 1.6 µm; 0.25 µm overlap between consecutive sections). Scale bars: 100 µm in C,D; 50 µm in A,B,F; 12.5 µm in E.