Developmental expression of sox11.

In situ hybridization with antisense probes for sox11a, sox11b, and shha was performed on whole embryos or on tissue sections at the indicated time points. (A) Sox11a and sox11b were expressed in the diencephalon adjacent to the optic vesicle (arrows in top row and asterisks in second row) at 18 hpf (top two rows) and 24 hpf (third and fourth rows). Sox11a expression was not detected in the lens or retina at 24 hpf (bottom left). Sox11b was expressed in a patch of cells in the ventronasal retina (arrow, bottom right) and more diffusely across the rest of the retina and lens. Top and third rows are dorsal views of flat-mounted embryos. Second and fourth rows are frontal sections through the head. Bottom panels are lateral views of dissected eyes; (n = 20 embryos examined per time point, 3 independent repeats). (B) Transverse sections through the eye at 48 hpf (top) and 72 hpf (bottom). Sox11a expression was detected in the ganglion cell layer (GCL) and in few sporadic cells in the inner nuclear layer (INL); sox11b expression was observed in scattered cells across the central retina and in the peripheral retina. At 72 hpf, sox11a expression persisted in the GCL and in some cells in the INL; sox11a and sox11b were also expressed in the persistently neurogenic ciliary marginal zone (CMZ); n = 20 embryos examined per time point, 3 independent repeats. (C) Expression patterns of sox11a (left), sox11b (center), and shha (right) in the developing brain at 18 hpf (top) and 24 hpf (bottom). The eye was removed to better image the brain. Expression of sox11a and sox11b, but not shha, was observed in the telencephalon. Expression of all three genes was detected in the hypothalamus and ventral diencephalon at 24 hpf (n = 20 embryos examined per time point, 3 independent repeats). Scale bar = 100 µm; D, dorsal; V, ventral; A, anterior; P, posterior; hpf, hours post fertilization; OV, optic vesicle; L, lens; R, retina; GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer; CMZ, ciliary marginal zone; tel, telencephalon; hy, hypothalamus; di, diencephalon.