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FIG. 8. Patched (Ptc) mRNA expression in normal development and with expression of SmoM2. (A) Whole-mount in situ hybridization
of uninjected (left) and SmoM2-injected (right) embryos at Nieuwkoop–Faber Stages 35, 40, and 45 using an antisense Xenopus Ptc
riboprobe. In normal development, activity of the Hh pathway, mirrored in Ptc mRNA expression, is highest around Stage 40, whereas
constitutive activation through SmoM2 results in Ptc overexpression at earlier stages. By Stage 45, Ptc expression is barely detectable in
control embryos and largely localized to the intestinal wall (arrows) in embryos overexpressing SmoM2. Staining with a sense probe was
consistently negative, as illustrated in a single representative of Stage 45 SmoM2 embryos. (B) In situ hybridization of sections of the intestine
of untreated (top) and Smo M2-injected (bottom) tadpoles at Stage 42, using radiolabeled Ptc antisense (center) or sense (right) riboprobes, showing
restriction of Ptc mRNA expression to the splanchnic mesoderm. Corresponding bright-field images are shown on the left. |
