Figure 1.

Development of the Schwann cell lineage. (A) During neurulation, the neural plate border (b) develops between the neural plate (a) and the non-neural ectoderm (c), along neighboring structures, including the notochord (d) and paraxial mesoderm (e). After the neural plate folds to build the neural tube (f), the neural plate borders merge and form the neural crest. Late neural crest cells (g) detach and migrate. (B) Differentiation along the Schwann cell lineage progresses through several intermediate stages, namely Schwann cell precursors and immature Schwann cells. While Schwann cell precursors are multipotent and can still differentiate into other cell types, such as melanocytes or neurons, immature Schwann cells are more fate restricted and differentiate into mature myelinating and non-myelinating Schwann cells, terminal Schwann cells of the neuromuscular junctions, as well as endoneurial fibroblasts. According to current knowledge, terminal Schwann cells segregate during differentiation prior to endoneurial fibroblasts and other Schwann cell subtypes.