Figure 2

nr4a2b is co-expressed with TH in the DA neurons of the preoptic area and in the amacrine cells of the retina. (A-H) Whole mount in situ hybridization showing nr4a2b expression pattern at 24 hpf (A, E), 48 hpf (B, F), 72 hpf (C, G) and 96 hpf (D, H). Dorsal (A-D) and lateral (E-H) views of the head are represented, anterior is to the left. (I-P") The spatial relationship between nr4a2b-expressing cells and CA neurons in different areas of the brain was analyzed by whole mount FISH to nr4a2b (green) and anti-TH immunohistochemistry (red). (I) Dorsal view (56 μm projection) of the head at 24 hpf. (J) Lateral overview (21 μm projection through the diencephalic DA groups) of a 72 hpf embryo. Scattered cells among THir neurons express nr4a2b but double labeled cells are not detectable in this region. A higher magnification of the framed area in J is showed in K (15 μm projection), and a dorsal view of the diencephalic clusters at the same developmental stage is presented in L (9 μm projection). (M) Single confocal plane showing the close proximity of nr4a2b-expressing cells to the THir NA neurons of the locus coeruleus at 72 hpf. Similar to nr4a2a, nr4a2b is co-expressed with TH in the preoptic area (N-N", 12 μm projection, 72 hpf) and in the amacrine cells of the retina (arrowheads in P-P", 7 μm projection, 96 hpf), but no co-expression is detectable in the pretectum at 96 hpf (O, 4 μm projection, approximate area framed in D). I, L, M, N-N", O, dorsal views; J, K, P-P", lateral views; anterior is to the left. Scale bar in A for A-C, E-G and in D for D, H: 100 μm; scale bars in I-P": 50 μm. Abbreviations: ACL, amacrine cell layer; HB, hindbrain; Hyp, hypothalamus; LC, locus coeruleus; PO, preoptic area; Pr, pretectum; PT, posterior tuberculum; T, tectum; Tel, telencephalon; Ret, retina.