MYRF Is a Membrane-Associated Transcription Factor That Autoproteolytically Cleaves to Directly Activate Myelin Genes
(A) DNA sequences (from 400–700 bp) encompassing the MYRF peaks proximal to the Cntn2, Trf, Mag, Mbp, and Plp1 genes (Figure 4) were cloned into pGL3 upstream of the SV40 promoter and luciferase gene and co-transfected into the CG-4 cell line with either empty (pCS6) or MYRF overexpression (pCS6-MYRF) vectors. Co-expression of MYRF strongly induces luciferase expression in the presence of these enhancers, but has no effect on luciferase activity in their absence. (B) The MYRF-bound regions identified upstream of the Mbp and Plp1 genes strongly promote luciferase expression in control oligodendrocytes relative to Myrf CKO oligodendrocytes, mirroring the loss of expression of MBP protein in the Myrf CKO cells (C). Fold inductions for all conditions are expressed relative to the pGL3-Promoter condition in control cells (pCS6 transfected in A, MyrfWt/Fl in B). Data are shown as means and SEMs from 4–5 independent experiments. *p<0.05, **p = 0.01, **p<0.001 based on two-way ANOVA with Bonferroni posttest.