Xenbase Image ID: 23831

Figure 2. Expression patterns of XLhx2 during eye formation in whole-mount (A,C,D) and sectioned (B,E-I) Xenopus embryos. A,B: XLhx2 is expressed in the eye field of the stage 12.5 embryo. Arrow shows expression is limited to the neuroectoderm. C,D: Anterior views show how the XLhx2 expression pattern resolves from a single eye field (stage 15) into the two eye primordia (stage 18). E: Evaginating optic vesicles and ventral forebrain stain throughout for XLhx2. Arrow and arrowhead point to presumptive retinal pigment epithelium (PRPE), optic stalk (OS), and presumptive neural retina (PNR), respectively. F: Dashed line outlines PRPE and PRN while arrow points to developing lens placode, where XLhx2 expression was undetectable. G: Neural retina (NR) expresses XLhx2, but lens vesicle (LV) does not. Arrows point to the peripheral retina where Lhx2 levels appear elevated. H: At stage 35/36, XLhx2 expression is reduced in the (a) presumptive outer nuclear and (b) ganglion cell layers. I: At stage 41, XLhx2 expression is limited to a subset of cells in the inner nuclear layer (INL) and ciliary marginal zone (CMZ, arrow and outlined in red). In G-I, the black dashed line denotes the border between neural retina and lens (Le). Dorsal is top in all panels. J-L: Relative expression patterns of the retinal transcription factors Lhx2, Pax6, Six3, Rx1, and Optx2 in the stage 41 Xenopus eye. J: Lhx2 expression is shown in light blue. K: Pax6, Six3, and Pax6 + Six3 expression is illustrated in blue, red, and violet, respectively. L: Rx1, Optx2, and Rx1 + Optx2 expression is illustrated in pink, yellow, and orange, respectively. At stage 41, the retina forms three nuclear layers. The outer nuclear layer (ONL - Rx1+) consists of rod and cone photoreceptors. The inner nuclear layer (INL) is subdivided into inner and outer regions. The outer INL (Rx1+; Optx2+; Six3+) contains mostly horizontal and bipolar cells while the inner INL (Lhx2+; Pax6+; Optx2+) contains mostly amacrine, Müller, and a few bipolar cells. The retinal ganglion cell layer (GCL) expresses Pax6, Optx2, and Six3. See the text for additional details of the expression patterns at these and earlier developmental stages. Image published in: Viczian AS et al. (2006) Copyright © 2006. Image reproduced with permission of the Publisher, John Wiley & Sons. Gene Synonyms Species Stage(s) Tissue lhx2.S lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. laevis Sometime during NF stage 12.5 to NF stage 41 eye lhx2.S lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. laevis Throughout NF stage 12.5 neuroectoderm lhx2.S lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. laevis Throughout NF stage 18 eye primordium lhx2.S lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. laevis Throughout NF stage 24 optic vesicle forebrain retinal pigmented epithelium retinal neural layer optic stalk lhx2.S lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. laevis Throughout NF stage 32 retinal neural layer lhx2.S lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. laevis Throughout NF stage 35 and 36 retinal outer nuclear layer retinal ganglion cell layer lhx2.S lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. laevis Throughout NF stage 41 retinal inner nuclear layer ciliary marginal zone Image source: Published Larger Image Printer Friendly View

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