Figure 1
Expression of Pbx1a in mesencephalic dopaminergic neurons. In situ hybridization using 35 S- (A, B) and digoxigenin-riboprobes (C-H, N, O) against TH (A, C, F, N), Pbx1a (B, D, O), Pbx1b (E), Pbx2 (H) and Pbx3 (G) on E11 sagittal (A, B) and coronal sections of E14 (C, D, E, H), E15 (F,G) and adult (N, O) mice. Fluorescent double labeling on coronal sections of E14 (I-K) and E15 (L, M) embryos using antibodies against TH (I, L) pan-Pbx (J) and Pbx3 (M). (A, B) At E11, TH expression is confined to mesDA neurons on the pial surface of the ventral mesencephalon (arrow) (A). The parallel section reveals the full extent of the Pbx1a expression with an elevated signal at the position of mesDA neurons (arrow) (B). (C-H) Pbx members’ expression in the ventral midbrain. Pbx1a (D) co-localizes with TH (C). Pbx1b (E) and Pbx2 (H) are not detectable in the ventral midbrain whereas Pbx3 (G) shows a diffused signal partially overlapping with TH (F). (I-K) Immunohistochemical double labeling using TH (I, green) and pan-Pbx (J, red) antibodies reveals the co-expression of Pbx1 and TH in mesDA neurons (K). (L, M) Double immunohistochemistry using TH (L, green), and Pbx3 (M, red) antibodies shows no detectable Pbx3 protein in the ventral midbrain. Insert: Pbx3 positive staining in raphe nucleus. (N, O) Expression of Pbx1a in the adult co-localizes with TH in ventral tegmental (VTA) and nigral (SN) dopaminergic neurons. Telencephalon (tel), diencephalon (di), mesencephalon (ms), hindbrain (hb). Dorsal to the top, A and B rostral to the right. Scale bars A-B, N, O = 500 μm, C-H, = 200 μm, and I-M = 100 μm. mesDA: mesencephalic dopaminergic.