Fig. 7

Insm1a acts upstream of pro-neural TFs ath5/atoh7 and neurod. (A) At 33 hpf ath5/atoh7 was expressed throughout the developing retina in controls; in contrast ath5/atoh7 expression was detectable only in the ventro-nasal patch of insm1a morphants (arrowhead). At 48 hpf, ath5/atoh7 expression in control retinas was restricted to the GCL; in insm1a morphant retinas, expression had expanded throughout the retina, in a pattern that closely resembled that of 33 hpf controls. (B) Neurod expression at 48 hpf was observed strongly in the developing photoreceptors and in the adjacent INL of control retinas. In insm1a morphants, however, neurod expression was mostly confined to the ventro-nasal retina (black arrowhead), with some expression throughout the central retina (gray arrowheads). In contrast, strong expression of neurod was observed in the olfactory epithelium (arrows) of insm1a morphants, which was absent in controls. By 72 hpf, neurod expression in the ONL (black bracket) and inner portion of the INL (blue bracket) was qualitatively similar in both controls and insm1a morphants. Scale bars=50 μm; D, dorsal; V, ventral; A, anterior; P, posterior; GCL, ganglion cell layer; oe, olfactory epithelium; ONL, outer nuclear layer INL, inner nuclear layer; hpf, hours post fertilization.