Fig. 8. Non-specifying adenohypophyseal cells of fgf3 mutants undergo apoptosis. (A-D,I,J) Nomarski images, (G,H) confocal images; frontal views onto the anterior border of the head, superimposed with fluorescent images of Acridine Orange stainings in green (C,D,J), or rhodamine cell labelings in red (G-J). All images are at same magnification; scale bar shown in (I) = 25 µm. In A-D,I, borders of the adenohypophysis are indicated with white arrowheads. All embryos were genotyped after evaluation and photography. (A) Nomarski images at 25 hpf; wild-type sibling; (B) fgf3 mutant, displaying a normal-sized adenohypophysis. For better contrast, images are not superimposed with Acridine Orange stainings, which showed no positive cells for wild-type (A), but few positive cells for mutant (B). (C,D) Acridine Orange stainings at 28 hpf; (C) wild-type sibling; (D) fgf3 mutant. (E,F) Summary of single cell-tracing experiments: cartoons showing the position of single cells from the anterior neural ridge region labeled at the tailbud stage, relative to mesodermal polster outlined in gray, which served as a landmark for the injections. A square corresponds to 50 µm x 50 µm. The fate of each cell is indicated by shape and color. Circles mark cells whose daughter cells were alive 28-30 hpf, crosses indicate cells that died during the course of the analysis, resulting in labeled cell debris only. Red circles mark adenohypophyseal clones, blue circles olfactory epithelium clones, yellow circles facial ectoderm clones, and salmon circles clones ending up in the head mesenchyme. Mixed clones with descendants in two different tissues are indicated with two-colored circles. Numbers and arrows mark cells with descendants shown in G-J. (E) Cells from wild-type siblings; (F) cells from fgf3 mutants. In F, red crosses represent clones with debris within and outside the shrunken adenohypophysis. Gray crosses are clones with debris outside the adenohypophysis only, which had not been investigated at 24 hpf. Therefore, their initial tissue belongings cannot be stated; however, they most likely derive from adenohypophyseal cells that had died early. (G) Descendants of wild-type cell 54 at 29 hpf. (H) Cell debris deriving from mutant cell 49. (I,J) Time course analyses of mutant cell 84. (I) 25 hpf; (H) same embryo at 30 hpf, counterstained with Acridine Orange.