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Fig. 5. Anterior shift of midbrain and hindbrain marker gene expression upon XRALDH2 overexpression. Roughly 2 ng XRALDH2 encoding mRNA was injected into one blastomere of two-cell stage embryos. β-Gal encoding mRNA was co-injected as a lineage tracer (light blue staining). The expression of the various marker genes (as indicated) was analyzed by whole-mount in situ hybridization analysis (purple staining). (a–d) Embryos were simultaneously probed with Otx2, Krox20 and Hoxb9. (a) Control. (b,c) Anterior view of injected embryos. The midbrain domain of Otx2 and two stripes of Krox20 are anteriorly shifted by one or two rhombomeric units in the injected (right) side. (d) Dorsal view of an injected embryo. Red triangles indicate that the anterior boundary of Hoxb9 expression was not altered. (e–h) Embryos were simultaneously probed with Otx2, En2, Krox20 and Hoxb9. (e) Control. (f–h) Anterior view of injected embryos. The midbrain domain of Otx2 and the stripes of En2 and Krox20 are shifted anteriorly in the injected side, however, the anterior boundary of Hoxb9 expression is not shifted (red triangles). |
