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Figure 1.
Xadam10 mRNA is expressed in the developing dorsal diencephalon and midbrain at the time RGC axons grow to the optic tectum. Expression of Xadam10 mRNA in a whole-mount brain and sections through the eye and brain at stages 32–37/38 as visualized by in situ hybridization with an antisense Xadam10 riboprobe is shown. A, Lateral view of a stage 33/34 whole-mount brain. Xadam10 mRNA is expressed in the dorsal diencephalon and optic tectum, but signal is much reduced in the ventral diencephalon. Similar expression is seen at stage 32 (data not shown). The inset shows a stage 40 brain with an HRP-labeled optic projection to compare the path taken by RGC axons with the expression of Xadam10 mRNA. B, Stage 32. Expression in the retina is widespread, including the RGC layer (brackets indicate the RGC layer, which is just forming) as indicated by immunolabeling for the Islet-1 transcription factor (inset), although little or no signal is observed in the developing outer nuclear layer (arrowhead). C, D, Stage 35/36. Xadam10 mRNA is still expressed in the dorsal diencephalon (C) and the optic tectum (D). The expected location of the distalmost part of the optic projection is indicated by asterisks, and insets show the location of HRP-labeled RGC axons (red-brown) in comparable brain sections. E, F, Stage 35/36. In a section through the more peripheral retina (E), Xadam10 mRNA is expressed in the innermost layers of the retina, including the RGC layer (indicated by brackets), as well the proliferative ciliary marginal zone. In sections through the central retina (F), Xadam10 mRNA expression is patchy (compare labeling in the RGC layer in both panels). G, Sense control at stage 33/34. H, By stage 37/38, Xadam10 mRNA is mainly localized to the inner nuclear layer and absent or greatly reduced in the outer nuclear and RGC layers. T, Optic tectum; Pi, pineal gland; Di, diencephalon; Ve, ventricle; ONL, outer nuclear layer; INL, inner nuclear layer; PE, pigment epithelium; cmz, ciliary marginal zone; L, lens; D, dorsal; V, ventral; Tel, telencephalon. Scale bar: (in H) A, 100 μm; C, D, 75 μm; B, E–H, 40 μm. |
