Electric-induced reversal of morphogenesis inHydra

ABSTRACT Morphogenesis involves the dynamic interplay of biochemical, mechanical and electrical processes. Here we ask: to what extent can the course of morphogenesis be modulated and controlled by an external electric field? We show that above a critical amplitude, an external electric field can halt morphogenesis in Hydra regeneration. Moreover, above this critical amplitude, the electric field can even lead to reversal dynamics: a fully developed Hydra folds back into its incipient spheroid morphology. The potential to renew morphogenesis is re-exposed when the field is reduced back to amplitudes below criticality. These dynamics are accompanied by modulations of the Wnt3 activity, a central component of the head organizer in Hydra . Reversal of morphogenesis is shown to be triggered by enhanced epithelial electrical excitations, accompanied by intensified calcium activity, indicating that electrical processes play an instructive role to a level that can direct developmental trajectories. Reversal of morphogenesis by external fields, calls for extending its framework beyond programmatic, forward-driven, hierarchical processes.