PRMT5-regulates developmental myelination

PRMT5 is important for gliomas, however its physiological function in oligodendrocyte progenitors (OPCs), remains poorly understood. Here we report PRMT5 to be responsible for symmetric di-methylation of histone H4R3 (H4R3me2s) in OPC. PRMT5 depletion via CRISPR/Cas9 decreased H4R3me2s, altered the OPC transcriptome, and decreased OPC survival. Strikingly, these changes were associated with a marked increase of H4K5ac in OPC, but not in gliomas. Consistently, ChIP-sequencing analysis revealed increased genome-wide distribution of H4K5ac in PRMT5 knockout cells. In vitro acetylation assays demonstrated reciprocal inhibition between symmetric arginine methylation and lysine acetylation. Low H4R3me2s and high H4K5ac levels were also detected in OPC in mice with lineage-specific ablation of Prmt5 (Olig1-Cre;Prmt5fl/fl), resulting in severely impaired developmental myelination. Importantly, pharmacological inhibition of acetyltransferase activity partially rescued the effect of Prmt5 deletion on oligodendrocyte-specific gene transcripts. Collectively, we identify PRMT5 as a critical modulator of histone acetylation and OPC differentiation in early developmental myelination. Overall design: (1) mRNA profiles of OPCs with or without PRMT5 expression were generated by deep sequencing, in tetraplicates, using Illumina HiSeq 2500.