loci were occupied with OLIG2 and modified with H3K9me3 (Fig. 6h), and H3K9me3 density was reduced in the promoter region of Sox11in the Setdb1 mutant iOLs (Supplementary Fig. 7g). ChIP-qPCR assay was performed to confirm the decreased H3K9me3 enrichment when OLIG2 was knocked down in the rat iOLs (Supplementary Fig. 7h). The regulation of Sox11 by OLIG2-SETDB1 complex was verified by luciferase assays. To avoid potential interference from endogenous SETDB1, we genearated Setdb1-deficient HEK293T cells (Supplementary Fig. 7i). OLIG2 inhibited Sox11 transcription with the exogenous SETDB1. In contrast, the enzymatic dead SETDB1 mutant (C798T)36 displayed almost no repressive effect on Sox11 expression (Fig. 6i). Next, we mutated two conservative OLIG2 binding motif in the promoter region of Sox11, OLIG2-SETDB1 complex is less potent to suppress Sox11 transcription (Supplementary Fig. 7j). To explore if the regulatory relationship between OLIG2-SETDB1 complex and SOX11 exits in vivo, we injected the Setdb1 mutant mice with ASO (modified antisense oligonucleotides) against Sox11 mRNA at P6, and brain tissues were collected at P14 (Supplementary Fig. 7k). Cy3-tagged ASO showed high efficiency in the forebrain (Supplementary Fig. 7l), and Sox11 was efficiently knocked down by ASO (Supplementary Fig. 7m). The MBP intensity was remarkably increased in the
