Figure 5

Nr4a2a is required for formation of DA neurons in pretectum, preoptic area and retina. Morphants were analyzed by WISH to detect th expression at 96hpf. (A) Embryos injected with control morpholino show normal formation of CA groups, including DA nuclei in the pretectum (arrowhead) and the preoptic region (arrow). (B) Injection of 2ng MOnr4a2, which targets both nr4a2 genes, leads to a strong reduction of DA neurons in the pretectum (arrowhead) and the preoptic region (arrow). (C) Control morphants form DA amacrine cells in the retina (arrow), which are absent or strongly reduced in embryos injected with MOnr4a2 (D). All the ventral diencephalic DA groups develop in the nr4a2 morphant embryos (F), including group 3 (arrow), although the spatial organization of the neurons appears altered when compared to control embryos (E). (G-H) When dat expression was analyzed (G, H), nr4a2 morphants showed lack of DA neurons in the pretectum (H, arrowhead), in the retina (inset in H) and the preoptic area (not shown). A-B, G-H: lateral views; C-F: dorsal views. Anterior is to the left. Scale bars in A for A-B, in E for E-F and in G for G-H: 100 μm. Abbreviations: LC, locus coeruleus; MO, medulla oblongata; OB, olfactory bulb; PO, preoptic area; Pr, pretectum; SP, subpallium.