Modulating myelination: knowing when to say Wnt.

Balancing extrinsic and intrinsic cues plays an integral part in shaping the complex architecture of the nervous system. During development, oligodendrocyte precursor cells integrate environmental signals and coordinate the activation of the transcriptional machinery necessary for differentiation and myelination. In this issue of Genes & Development, Fancy and colleagues (pp. 1571-1585) demonstrate that canonical Wnt signaling contributes to the decision of an oligodendrocyte precursor cell to differentiate-both during development and after demyelination. These findings provide new insight into the precise spatiotemporal coordination required for oligodendrocyte development.