β-catenin Dynamics in Regenerating Hydra

Abstract

Body axis specification is essential for morphogenesis, yet how axial patterning is dynamically coordinated remains unclear. In Hydra, Wnt/{beta}-catenin signaling is central to axial patterning, but its spatiotemporal dynamics are not well understood. Since nuclear {beta}-catenin mediates Wnt-dependent transcription, its localization provides a relevant readout for pathway dynamics. Here, we track {beta}-catenin abundance and nuclear localization in vivo during regeneration from bisected Hydra, tissue rings, and small tissue fragments. Following bisection, nuclear {beta}-catenin is detected exclusively at the regenerating oral end, where a broad signal appears and then declines before focusing at the future head. Tissue rings, lacking both head and foot, exhibit similar oral-aboral asymmetry. In regenerating fragments, the initial response often spans nearly the entire tissue, including the future foot region, followed by an additional peak before stabilizing at the future head. Overall, our results show that the spatial restriction of nuclear {beta}-catenin correlates with the divergence of regenerative dynamics toward head or foot formation, while the trajectories leading to these outcomes vary across different initial tissue configurations.