Figure 4. ISH analyses of target gene expression in the context of in ectopic β-catenin activation in vivo. A-C: Serial cryosections of Control (Cntr) and in β-cat^Act retinas at E14.5 were analyzed for expression of the indicated genes by ISH or for expression of the Tcf-LacZ reporter transgene with X-gal staining. The dotted outlines indicate the expanded CM region in the β-cat^Act retina, which is marked by X-gal staining (A, B) or expansion of Msx1 expression (A, C). Each lettered image grouping represents a separate serial series. Sections were cut in the horizontal plane. n/t indicates the nasal/temporal orientation of the eyes in all images. Note that X-gal staining for the Tcf-reporter in wild-type mice is lower than previously reported, because the tissue was fixed overnight.