Fig. 2

GFP expression pattern of ETvmat2:GFP embryos. Photos were taken under a fluorescence microscope in lateral (A, C, G), dorsal (B, E, F, H) and ventral views (D), or under a confocal microscope in dorsal view (I), rostral to the left. (A) A 24 hpf embryo showing the first GFP-positive (GFP⁺) neurons that appear in the nervous system; (B) a 30 hpf embryo showing GFP⁺ neurons in posterior tuberculum (PT) and their early axons projecting both anteriorly and posteriorly (asterisks), and some faintly labeled neurons in the paraventricular organ (Pa); (C) a 36 hpf embryo showing GFP⁺ neurons in the locus coeruleus (LC) located in the ventral lateral region of rhombomere 1; (D) a 54 hpf embryo showing the GFP⁺ arch-associated neurons (AAN) rostral to the heart; (E) a 60 hpf embryo with GFP⁺ neurons in the LC, the raphe nuclei (Ra) and the pretectum (Pt); (F) a 72 hpf embryo with GFP⁺ sympathetic neurons (Sym) under the artery; (G, H) 5 dpf embryos showing GFP⁺ neural groups in the central and peripheral nervous systems; (I) a 4 dpf embryo showing GFP⁺ neurons in PT and Pa, with the PT neurons sending out prominent single lateral neurites (asterisks). Scale bar: 25 μm. AAN: arch-associated neurons; Hc: caudal hypothalamus neural cluster; Hi: intermediate hypothalamus neural cluster; LC: locus coeruleus; MO: medulla oblongata neural cluster; Pa: neural cluster of paraventricular organ; Pt: pretectal neural cluster; PTa: anterior group of the posterior tubercular neurons; PTp: posterior group of the posterior tubercular neurons; Ra: raphe nuclei; SC: spinal cord; Sym: sympathetic neurons; Te: telencephalic neurons. Arrowheads in panels A and H: GFP-positive neurons in midbrain.