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Fig. 3 Lineage tracing of Neurog1+ cells juxtaposing the meso-diencephalic boundary. A-C: Schematic representation of 1- to 3-somite stage neurog1::gfp embryos (anterior to the left, lateral view) that were injected with caged dextran-fluorescein at one-cell stage. The tracer dye was uncaged at the anterior dorsal (A; n = 3), anterior ventral (B; n = 5), and posterior ventral (C; n = 3) areas of a discrete Neurog1+ domain located at the posterior diencephalic anlage. The boundaries of each of the uncaged clones were measured in relation to the depicted Neurog1+ domains that served as live neural plate landmarks. A′-C′: Schematic representation of the fluorescein-labeled cells at the prim-5 stage (24 hours). A″-C″: Representative images of 24 hr postfertilization (hpf) embryos that underwent uncaging followed by immunofluorescence staining of the uncaged form of the fluorescein and of tyrosine hydroxylase (TH)- positive dopaminergic (DA) neurons. The fluorescein-labeled cells marked the thalamus (Tha; A″), dorsal posterior tuberculum (PTd; B″), and ventral tegmentum (vTg; C″). Neurog1+ cells (not to scale) are depicted by green spheres and dopaminergic neurons are marked in purple. Dien, diencephalon; PO, preoptic nucleus; PTv, ventral posterior tuberculum; Tel, telencephalon; TG, trigeminal ganglion. Scale bar = 25 μm.