Figure 7. CHD8 regulates H3K4me3 deposition at the promoters of oligodendrocyte genes through interaction with ASH2L and WDR5.

(A) CHD8 co-immunoprecipitated with ASH2L and WDR5.

(B) Levels of Chd8 mRNA in rat OPCs treated with Chd8 siRNA (siChd8) or control siRNA (Ctrl).

(C) Enrichment of ASH2L, WDR5, and H3K4me3 in promoter regions of oligodendrocyte genes in control and siChd8-treated OPCs.

(D, E) Ash2L and Wdr5 (D) and myelin gene (E) mRNA expression in cultured OPCs treated with siRNAs targeting Ash2L or Wdr5. Data are presented as means ± s.e.m. (n = 3 experiments; ** p < 0.001, two-tailed unpaired Student’s t test).

(F) CHD8 immunostaining in OPCs from control and Chd8 cKO cortices. Scale bar, 100 μm.

(G, H) H3K4me3 immunostaining in control and Chd8 cKO OPCs treated with vehicle or CPI-455. Scale bar, 100 μm. Panel H, percentage of H3K4me3⁺ oligodendrocytes among total cells.

(I, J) MBP and Olig2 immunostaining in control and Chd8 cKO OPCs treated with vehicle or CPI-455. Scale bar, 100 μm. Panel J, percentage of MBP⁺ oligodendrocytes among total Olig2⁺ cells.

(K, L) CC1 and MBP immunostaining of spinal cords from control and Chd8 cKO littermates treated with vehicle or CPI-455 and harvested at P14. Scale bar, 100 μm. Panel L, quantification of CC1⁺ oligodendrocytes.

(M) A schematic model showing that CHD8 executes a dual function by establishing an accessible chromatin landscape and recruiting KMT2/MLL histone methyltransferase to activate the transcriptional program for oligodendrocyte lineage progression.