Developmental shift in β-catenin localization between nuclear and junctional pools during vertebrate nephron development

Wnt/{beta}-catenin signaling is a critical pathway that regulates nephron progenitor renewal versus differentiation as well as nephron patterning. In addition to its role as a transcription co-factor, {beta}-catenin also functions as a structural component of adherens junctions, where it interacts with cadherins to link cell-cell contacts to the cytoskeleton. However, the relationship between the nuclear and junctional localization of {beta}-catenin during vertebrate nephron development remains poorly understood. To define how endogenous {beta}-catenin localization changes during nephrogenesis, we optimized an accelerated-turnover {beta}-catenin chromobody for live imaging in Xenopus embryos. Using in vivo imaging of Xenopus pronephric development, we visualized endogenous {beta}-catenin within the nuclear, cytoplasmic, and junctional compartments. Across successive developmental stages, {beta}-catenin became progressively enriched at epithelial junctions during nephron maturation while remaining abundant within nuclear and cytoplasmic compartments. Quantitative analyses indicate that epithelial maturation is accompanied by coordinated expansion and partitioning of multiple intracellular {beta}-catenin pools rather than a simple redistribution from nuclear to junctional compartments.