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Figure 4.
Nrarp overexpression blocks Notch signaling in embryos. Xenopus embryos at the two-cell stage were injected with RNA encoding Nrarp along with LacZ RNA as a tracer. At neural plate stages, embryos were fixed, stained for β-galactosidase expression, and double-labeled by whole-mount in situ hybridization for markers of neurons or ciliated cell precursors. (A) Nrarp overexpression induces the formation of additional primary neurons (arrow) as shown by the expression of a neural isoform of β-tubulin (N-Tub). Shown is dorsal view of the neural plate with the injected side oriented to the top of the panel. (B,C) Nrarp overexpression induces additional ciliated cell precursors that form in the skin as shown by the expression of an isoform of α-tubulin (α-Tub) (Deblandre et al. 1999). The uninjected and injected sides of the same embryo are shown in panels B and C, respectively. (D–F) Dorsal view of the neural plate with the injected side oriented up. Note that Nrarp overexpression induces more XDelta1 expression (D) but reduces the expression of ESR1 when scored at stage 12 or stage 14 (E and F, respectively). |
