The Transcription Factors EBF1 and EBF2 Are Positive Regulators of Myelination in Schwann Cells.

Myelin formation by Schwann cells is tightly controlled by multiple pathways and regulatory molecules. The Ebf2 gene, belonging to the Ebf family of transcription factors regulating cell development and differentiation, is expressed in Schwann cells, and Ebf2 knockout mice show peripheral nerve defects. We also found that Ebf1 is expressed in Schwann cells. To investigate Ebf function in myelination, we silenced Ebf genes in myelinating dorsal root ganglia cultures. Combined downregulation of Ebf genes leads to a severe impairment of myelin formation that is completely rescued by their specific overexpression, suggesting that the expression level of Ebf genes strongly influences axon myelination. In addition, by profiling Ebf target genes, we found several transcripts belonging to pathways actively involved in peripheral myelination, including Gliomedin, a gene with a role in the formation of the nodes of Ranvier and recently implicated in the pathogenesis of the nodo-paranodopathies. Our results suggest that Ebf genes act as positive regulators of myelination and directly regulate the promoter of Gliomedin.