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Fig. 8. Increasing Pax6 levels at stage 12 does not alter stem cell marker genes but represses sox2 and differentiation marker genes. (A) rx1 expression in the optic vesicle (arrowhead) is larger (cf. Fig. 5B). (B) At stage 38, rx1 expression is similar to controls and no repression surrounds β-Gal-labeled nuclei (arrowheads). (C) six3 expression in the optic vesicle (arrowhead) is not different from the control side. (D) At stage 38, no repression of six3 expression surrounds β-Gal-labeled nuclei (arrowhead). (E) notch1 expression in the optic vesicle on the injected side (arrowhead) is similar to the control side. (F) At stage 38, no repression of notch1 expression surrounds β-Gal-labeled nuclei (arrowheads). (G) When Pax6-GR protein is activated at stage 12, the sox2 expression domain in the optic vesicle is smaller (arrow). (H) When Pax6-GR protein is activated at stage 16, sox2 expression in the optic vesicle domain is smaller (arrow), but in the neural plate (np) it is broader and is ectopically expressed (arrow, inset). (I) ngn1 expression in the optic cup (arrowhead) is fainter and reduced in size (cf. Fig. 5L). (J) At stage 38, repression of ngn1 in β-Gal labeled cells persists (arrowheads). (K) p27 expression in the optic cup (arrowhead) is fainter and reduced in size (cf. Fig. 5N). (L) At stage 38, repression of p27 expression in β-Gal labeled cells (arrowheads) persists. (M) neuroD expression in the optic cup is fainter and reduced in size (cf. Fig. 5P). (N) At stage 38, neuroD expression remains repressed (arrowheads) in only a small number of embryos (Table 2). (O) Xath5 expression in the optic cup (arrow) is fainter and reduced in size (cf. Fig. 5R). (P) At stage 38, Xath5 expression remains repressed in β-Gal labeled cells (arrowhead) in a small number of embryos (Table 2). Data for stage 16 activation (except for sox2, see H above) are similar albeit at significantly lower frequencies at stage 38 for ngn1 and p27 and at higher frequencies for neuroD and Xath5 (Table 2). Dashed lines indicate the outline of the retinas in the sectioned material. For whole mounts, bars = 100 μm; for sections bars = 20 μm. |
