Playing the Field: Sox10 Recruits Different Partners to Drive Central and Peripheral Myelination

Abstract

Within the vertebrate nervous system, specialized glial cell types ensheath the axons of neurons with multiple wraps of membrane (myelin) in order to increase the speed and efficiency of nerve conduction. In the central nervous system, this role is fulfilled by oligodendrocytes; Schwann cells carry out the equivalent function within the peripheral nervous system. In spite of their common function, there are some substantial differences between oligodendrocytes and Schwann cells. For starters, they have different embryonic origins, arising from the neural tube and neural crest respectively. Each oligodendrocyte may myelinate anywhere from 1 to 50 axons, whereas a myelinating Schwann cell will devote its energy to a single axon. Even the major protein components of myelin in the peripheral and central nervous systems are a somewhat inexplicable mix; both incorporate the Myelin Basic Protein (MBP), but the major peripheral myelin protein, Protein Zero (P0), is replaced in the central nervous system with Proteolipid Protein (PLP). The transcription networks underlying differentiation and myelination in each cell type are also largely distinct, although one consistency is that the HMG-domain transcription factor Sox10 is required for successful myelination by both cell types [1], [2].