Modifying membrane potential synchronously controls the somite's formation periodicity and growth

Abstract

Coordination between periodicity of somite formation and somite growth is crucial for regular body pattern formation during somitogenesis. Yet, the specific mechanism that links the two processes remains unclear. Using chick embryos, we demonstrate that both temporal and spatial features can be simultaneously controlled by membrane potential (V_m) of somite-forming cells. Our findings show that somites hyperpolarize as they mature, displaying step-like changes in V_m observed between specific groups of somites, reflecting the reported onset of biochemical and structural changes within them. We modify V_m by changing chemical compositions of the microenvironment of the embryo. Alteration of V_m sets a new pace of somite formation (cell migration and self-assembly) and its concurrent growth (cell proliferation) without disturbing the somite's regular aspect ratio. Our results therefore suggest that V_m has the ability to orchestrate cell proliferation, migration and self-assembly - processes that are hallmarks of embryogenesis, tumorigenesis and tissue regeneration.

Keywords: Cell electrophysiology; Chick embryo; Glass microelectrodes; Membrane potentials; Periodicity of somite formation; Somite growth.