Figure 1.

Expression of transcription factors during oligodendrocyte (OL) differentiation. Expression levels of relevant transcription factors in OPCs, premyelinating OLs, and myelinating OLs. The intensity of the shading reflects the expression level relative to the gene’s peak level within the lineage. Note the high expression of inhibitors of differentiation and myelination (Hes5, Id2, Id4, Sox5, and Sox6) in OPCs, all of which are rapidly down-regulated at the premyelinating stage. Tcf7l2 and Zfp488 show a more transient expression during differentiation, suggesting a relatively specific role during differentiation. Factors including myelin regulatory factor (Myrf), Zfhx1b, Smad7, and Nkx6-2 show later expression, consistent with their roles in myelination and beyond. (Expression data from Cahoy et al. 2008.)