Spinal cord stem cells Injuries to the mammalian spinal cord do not heal easily. Llorens- Bobadilla et al. studied mouse ependymal cells, which function as stem cells for the spinal cord (see the Perspective by Becker and Becker). Chromatin accessibility and transcriptomic assays revealed that these cells carry a latent ability to differentiate into oligodendrocytes, which is much needed for remyelination of axons around an injury. The ependymal cells were triggered to differentiate into oligodendrocytes by expression of the oligodendrocyte lineage transcription factor OLIG2. Expression of OLIG2 in ependymal cells specifically and inducibly enabled the production of oligodendrocytes. The ependymal-derived oligodendrocytes aided axon remyelination and improved axon conduction after spinal cord injury. Science , this issue p. eabb8795 ; see also p. 36