Fig. 5: Med23 controls a regulatory network critical for OPC differentiation.

a t-SNE analysis of RNA-seq data of Med23^+/+ iOLs and Med23^–/– iOLs. b RNA-Seq transcriptome profiling changes between Ctrl and Med23^–/– iOLs. Representative transcripts of genes with downregulated expression (blue) or upregulated expression (red) are shown. c Gene ontology enrichment analysis showing the significantly altered genes between Ctrl and Med23^–/– iOLs. d, e Heatmaps showing the expression differences in OL differentiation-associated genes (d) and cholesterol metabolism-related genes (e) between Ctrl and Med23^–/– iOLs. f, g qRT-PCR analysis of OL differentiation-associated genes and cholesterol metabolic genes between Ctrl and Med23^–/– iOLs. Gene expression was normalized to that of 18S rRNA. h Enriched motifs in the promoter regions of significantly downregulated genes in Med23^–/– iOLs. i WT and Med23-KO HeLa cells were transfected with luciferase reporters driven by the Fyn, Mbp, Hmgcr, or Ldlr promoter together with expression vectors carrying Sp1. Values are presented as firefly luciferase activity normalized to co-transfected GFP fluorescence activity. j Sp1-targeted GC-box and GG-box reporter activity in WT and Med23-KO HeLa cells. k Sp1 activation domain fused to Gal4-DNA binding domain was tested for ability to activate transcription in WT and Med23-KO HeLa cells. The data are presented as the mean ± SEM; n = 3 independent experiments. Two-tailed unpaired Student’s t-test, *P < 0.05, **P < 0.01, and ***P < 0.001.