Fig. 4

Misexpression of ngn1 leads to supernumerary DA neurons in the forebrain and induces TH⁺ cells with an apparent neuronal morphology on the yolk surface ectoderm. (A–H) Immunostaining with TH antibody (A–F) and in situ with DAT antisense probe (G and H) shows that DA neurons are significantly increased in the ventral forebrain and ectopically induced in the telencephalon (Di DA neurons are out of focal planes in E–H) in ngn1-mRNA injected embryos. (I and J) Immunostaining with TH antibody showing an ectopic TH⁺ cell on the yolk surface ectoderm of ngn1-injected embryo. (K and L) A high magnification view of (I and J), and Inset showing an ectopic TH⁺ cell with an apparent neuronal morphology on the yolk surface ectoderm. DA, dopaminergic neurons; DAT, dopamine transporter; di, diencephalon; LC, locus coeruleus; mhb, midhindbrain boundary; t, telencephalon. (Scale bar, 15 μm in K and L, 32 μm in A–H, and 64 μm in I and J.)