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		expression. The experimental embryos exhibited a greater amount of shh staining in both the limb buds and craniofacial region than the control embryos. In the limb buds the domain of shh expression extended to the anterior portion of the limb bud, whereas in the controls shh was confined o the posterior portion of the limb buds. Both the control and experimental embryos show staining along the notochord (Figure 3). (a)control/shh (b)SU5402/shh Figure 3. Embryos processed with DIG labled shh antisense probe. (a) embryo treated with DMSO exhibits less shh expression (b) interfering with FGF signaling resulted in greater shh expression in the craniofacial and limb bud regions(white arrows) as well as the branchial arches.	. . .