Xenbase Image ID: 134702

Fig. 3. Morphological changes in rax mutant embryos can be detected by St. 21, prior to differential expression of key EFTFs, but following up-regulation of arx. Up-regulation of telencephalic marker foxg1 is also observed by St. 21. (A) Histological sections through St. 20 and St. 21 embryos reveal no detectable change in optic vesicle morphology at St. 20, but a lack of thinning of the posterior optic vesicle wall in mutant embryos at St. 21 (red arrows). The plane of sectioning is indicated above, and is the same plane for all stages shown throughout (serial sections were carefully examined to correctly match the plane of sectioning). The anterior and posterior ends of sections are marked A and P, respectively. (B) Examination of key EFTFs (pax6 and lhx2 shown) by in situ hybridization at St. 18 and St. 21 reveals no detectable change in expression. (C) By St. 19, anterior expansion of the arx expression domain is observed in mutant embryos (blue arrows). This expansion becomes more pronounced at St. 21 (red arrows). (D) Examination of telencephalic marker foxg1 at stages 21 and 24 reveals lateral expansion in rax mutant embryos (red arrows). At stage 24, lateral bulging of the optic vesicles can be observed in whole embryos from an anterior view (white arrows); these bulges are not observed in rax mutant embryos, and foxg1 expression is expanded into a region of the territory the optic vesicle would occupy in wildtype embryos. (E) Histological sections at St. 26, St. 28 and St. 30 show the increasing divergence of wildtype and mutant morphologies. By St. 30, the optic cup and lens tissue are forming in wildtype embryos (black arrows and arrowhead, respectively), but typically fail to form in rax mutant embryos. In panels A and E, a minimum of three embryos for each stage and genotype were sectioned and consistently displayed the shown morphology. Scale bars in panels A and E measure 75 μm. Image published in: Fish MB et al. (2014) Copyright © 2014. Image reproduced with permission of the Publisher, Elsevier B. V. Gene Synonyms Species Stage(s) Tissue arx arx-a, arx-b, ct121, issx, mrx29, mrx32, mrx33, mrx36, mrx38, mrx43, mrx54, mrx76, mrx87, mrxs1, prt5, xARX X. tropicalis Sometime during NF stage 18 to NF stage 21 diencephalon neural plate optic vesicle pax6 an2, mgda, pax-6, pax6-a, pax6-b, wagr, XLPAX6, xpax6 X. tropicalis Sometime during NF stage 18 to NF stage 21 eye retina diencephalon pre-chordal neural plate neural tube lhx2 lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. tropicalis Throughout NF stage 18 eye retina optic vesicle eye primordium lhx2 lhx2-a, lhx2-b, x-Lhx2, XLhx2 X. tropicalis Throughout NF stage 21 eye retina diencephalon pre-chordal neural plate optic vesicle neural tube foxg1 bf1, foxg1b, LOC108700624, XBF-1, XBf1 X. tropicalis Throughout NF stage 21 forebrain pre-chordal neural plate telencephalon foxg1 bf1, foxg1b, LOC108700624, XBF-1, XBf1 X. tropicalis Throughout NF stage 24 eye retina forebrain telencephalon optic vesicle Image source: Published Larger Image Printer Friendly View

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