Fig. 4

Schematic representation of the DNA modifications cycle, including factors responsible for the transitions between states. a Overall DNA modifications cycle; b Diagram summarising the known involvement of DNMTs and TET enzymes in OLG differentiation, developmental myelination, and in remyelination in response to injury. Evidence shows an age dependent role for DNMT1 and DNMT3A, with the former suggested to be more important in developmental myelination, and the latter in the remyelination involving differentiation of adult OPCs [68, 71]. Whilst it has been suggested that all three TET enzymes are involved in oligodendrocyte differentiation [120], TET1 has been reported to be more important for myelination and remyelination after injury [38, 69]. DNMT1/3A/3B—DNA methyltransferase 1/3A/3B, TET—ten-eleven translocation enzymes, TDG—thymine DNA glycosylase. Figure created with BioRender