Fig. 3. Reception of Nodal signals is required for cells to contribute to the PV but not the AD hypothalamus. Embryos in which wild-type and/or MZoep cells, or wild-type cells expressing Fast1^SID, were transplanted into the prospective hypothalamus of wild-type hosts are shown. Genotypes are indicated in the top left-hand corner (donor>host). (A-F) Live embryos in which transplanted cells are visualized with GFP (green) or rhodamine-dextran (red). (A) Dorsal view of a shield stage embryo with rostral upwards. The blastoderm margin is indicated by broken line. At this stage, hypothalamic precursors are close to the shield, some distance from the front of the neural plate. (B-C) Lateral views of bud stage embryos with anterior to the left. The anterior limit of the prechordal mesendoderm is indicated by white dots. By this stage, hypothalamic precursors have reached the front of the neural plate. (D-F) Lateral views of brains of 28 hpf embryos with anterior towards the left. (G-L) Frontal sections through the hypothalami of 28 hpf embryos, showing ß-gal+ transplanted cells (brown) in relation to the expression of various hypothalamic markers (indicated in the bottom right-hand corner). AD and PV, anterior dorsal and posterior ventral hypothalamus; or, optic recess. Scale bars: 60 µm.