BMI1 associates with CBX proteins to repress HbF in adult erythroid cells. (A) Representative immunoblots of BMI1 and different ancillary subunits (CBX2, 4, 6-8, and RYBP) in primary adult erythroblasts coimmunoprecipitation (co-IP) experiments. (B) Volcano plots of DEGs identified from CBX2, 4, and 8 triple depletion RNA-seq experiment in HUDEP2 cells by DESeq2. Cutoff threshold: fold change > 2; FDR < 0.1; n = 2. (C) Representative immunoblots of CBX2, 4, and 8, and IGF2BP1, LIN28B, and γ-globin protein in nuclear extract or whole-cell lysate of control and CBX2, 4, and 8 triple-depleted HUDEP2 cells. Lamin B1 and GAPDH were used as loading controls for nuclear extract and whole cell lysate respectively. (D) Enrichment plots of BMI1-repressed genes overrepresented in CBX2, 4, and 8 triple depletion RNA-seq in HUDEP2 cells as determined by GSEA. (E) Chromatin occupancies of BMI1, RING1B, EZH2, CBX2, 4, 7, and 8 in primary adult erythroblasts at the IGF2BP1 gene region. (F) Chromatin enrichment of H3K27me3 and H3K4me3 at IGF2BP1 gene in control or CBX2, 4, and 8 triple-depleted HUDEP2 cells. DEGs, differentially expressed genes; GSEA, gene set enrichment analysis.