Detection of nuclear beta-catenin in Xenopus embryos.

Immunodetection of beta-catenin accumulation in the nucleus is the most direct and reliable method to determine the intensity and the spatial/temporal patterns of Wnt-dependent signaling activity. Due to the large size of the Xenopus embryo, staining must be done on sections. We present here a simple protocol to prepare cryosections and produce high-quality images of the early embryo using immunofluorescence. We also provide comments on various conceptual and technical issues from fixation to image collection, which may assist in optimizing immunodetection in embryos and tissues beyond the specific scope of beta-catenin localization.