Fig. 6. Schwann cell development.

Neural crest cells give rise to a series of cell types in the Schwann cell lineage, one or more of which can become a neurofibroma initiating cell (NIC) following biallelic NF1 loss. Plexiform NICs are thought to be derived from Schwann cell precursors or their more differentiated progeny in deep peripheral nerves; alternative origins such as boundary cap cell or satellite cells have also been proposed. Another progenitor population arising from the neural crest has been located in the dermis, and dermal NICs may arise instead from these skin-derived precursors (SKPs) or their progeny. Times indicated are the embryonic days (E) at which specific Schwann cell precursors appear in the mouse. Listed below each cell type are useful markers of specific developmental stages and promoters which are active at these stages (see text for further discussion). Note that promoters used to drive Cre-mediated recombination are often fragments of whole gene promoters and may have a separate designation (i.e. P₀a is a 1.1kb fragment of the P₀ promoter, and 3.9Periostin is a 3.9kb fragment of the periostin promoter).