Localization of nelf mRNA (in situ hybridization, red signals) in relation to GnRH3 cells and projections (immunocytochemistry for enhanced green fluorescent protein, green signals) in developing zebrafish. Diagrams show the orientation of the confocal micrographs (dorsal view of embryo head, anterior is top, H-I and K-L are different Z depths). Dashed line depicts the forebrain edge (C,F). A-C: At 26 hpf, GnRH3 cells (arrowheads) are in the olfactory epithelium, nelf mRNA is expressed in the telencephalon. C: Enlargement of boxed area in B. D-F: At 32 hpf, nelf expression in olfactory epithelium around and within GnRH3 neurons (arrowhead), in olfactory bulb (arrows) and presumptive hypothalamus (asterisks). G-I: At 48 hpf, GnRH3 axons project caudally along the path of the terminal nerve and intersect at the optic chiasm (arrowhead) and then proceed to innervate the retina. nelf is expressed within GnRH3 neurons in the terminal nerve (see also Fig. 5D-F). nelf is expressed in the olfactory bulb (arrows), telencephalon domain adjacent to the anterior commissure (asterisks), and in the midbrain (double crossed arrows). J-L: At 72 hpf, GnRH3 neurons in the terminal nerve no longer express nelf. nelf is expressed in olfactory bulb (arrow) and telencephalic domains (asterisks). Scale bar = 20 μM in C,F, 50 μM all other subfigures.
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