Discovery of oligodendrocyte enhancers that regulate Sox10 expression.

Oligodendrocytes (OLs) assemble myelin sheaths around axons in central nervous system (CNS). Myelin is essential for the saltatory conduction of action potentials and also performs other critical functions for the operation of the CNS. Sox10 (SRY-box containing gene 10) is a high-mobility group transcription factor that orchestrates the development of OLs. Despite its key role in OL biology, there is scant information on how the expression of Sox10 is regulated in OL lineage cells. Especially, OL enhancers that control its transcription remain elusive. We have recently developed an innovative method that rationally links OL enhancers to target genes. This study applied the new method to Sox10, uncovering two OL enhancers for it (termed Sox10-E1 and Sox10-E2). Epigenome editing analysis revealed that Sox10-E1 and Sox10-E2 regulate Sox10 expression non-redundantly. Luciferase assay and human and mouse brain multi-omics data show that, during the differentiation of OL precursor cells (OPCs) into OLs, the enhancer activity of Sox10-E1 does not change while that of Sox10-E2 decreases significantly. Chromatin interaction data indicate that the two Sox10 enhancers lie close to the border of the Sox10 topologically associating domain (TAD). Consistently, Pick1, a gene that is near the Sox10 TAD border, is also under the transcriptional control of Sox10-E1 and Sox10-E2. Hence, genomic deletions involving Sox10-E1 and Sox10-E2 would perturb not only SOX10, but also PICK1 and other genes, and may cause a pathology that is more complex than that of conventional Waardenburg-Shah syndrome that results from SOX10 coding mutations.