Figure 1.

Neural tube formation involves a series of biological processes including mechanochemical signal sensing from the environment to orchestrate cell proliferation, cytoskeleton remodeling, and migration of neural and non-neural ectodermal cells. (a) Neural plate cells undergo convergent-extension to facilitate posterior-anterior elongation of the neural tube. Neuroectodermal cells (NE) migrate to the midline in response to extracellular signals received by cilia in NE cells to establish and maintain polarity. (b) Midline NE cells undergo apical constriction via a biological process involving actomyosin cytoskeleton remodeling to form the midline hinge point (MHP). NE cell and non-neuroectodermal (NNE) cells continue proliferation and migration during the neural tube closing process upon sensing signals in the extracellular matrix (ECM). NE cells at the dorsolateral hinge point (DLHP) undergo proliferation, migration dorsally, and reshaping to form the DLHP bringing the NE/NNE edges at the dorsal midline together. Advancing migration and proliferation of NNE and mesenchymal cells facilitate ectodermal layer extension when dorsal midline cells’ protrusions meet and join at the closing point. The process also brings NE cells together to establish cell junctions and close the NT.