Localization of staufen expression in the developing zebrafish embryo by whole mount in situ hybridization. (A–C) In situ hybridization was performed on 4-cell stage embryo (A). (B) Localization of vasa on 4-cell stage embryo. (C) A negative control in situ hybridization using the zebrafish staufen sense probe. In situ hybridization performed on 16 somite (D and E), 25 somite (F and G) and 24-h embryos (H). (D and E) The 16 somite embryo shows staufen staining in the telencephalic ventricle (TV) from the dorsal view. The neural tube (NT) is also staufen positive. (F and G) The 25 somite embryo shows staufen expression to be present in the telencephalic (TV), diencephalic (DV), rhombencephalic (RV) ventricles as well as in the neural tube. (H) The 24-h embryo continues to express staufen in the developing nervous system. The asterisk marks the eye vesicle. Magnification bar=100 μm.

(A) Characterization of staufen expression in tissues of the adult zebrafish using Northern blot analysis. Twenty microgram of total RNA from brain, heart, gut, muscle, ovary, and testis were separated by electrophoresis on 1% agarose/formaldehyde gels and transferred to nitrocellulose membranes. The membranes were hybridized with ³²P labeled staufen cDNA probes and exposed to X-ray film. Ethidium bromide staining of 28S and 18S rRNA served as loading controls. (B) Localization of staufen expression in the adult brain by in situ hybridization. Axonal tracts and processes (AP) located on the ventral surface of the brain express staufen. (C–E) Staufen in situ hybridization in sectioned zebrafish brain. (C) Staufen expression in the descending trigeminal root (TG), descending octaval nucleus (ON), and in nuclei of the primitive cerebellum (Ce). (D) Staufen expression in the periventricular gray zone (PVG) of the optic tectum and the thalamus (T). (E) Staufen expression in the vulvula cerebelli (Vce). Localization of staufen expression in the adult zebrafish testis by whole mount and sectioned in situ hybridization. (F) Whole mount in situ hybridization. (G) Cross section of the zebrafish testis demonstrating staufen localization in the Leydig cell (LC). Magnifications: B and G=100 μm; C, D, and E=2 mm; F=1 mm.

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