CTCF is selectively required for maintaining chromatin accessibility and gene expression in human erythropoiesis [ChIP-seq_GATA1]

By using an unbiased genetic screen and proteome profiling in human erythroblast, we identified and verified KMT2D as an essential factor for human erythropoiesis. Accordingly, we observed that KMT2D is indispensable for the activation of erythroid signature genes in a stage dependent manner. Moreover, to further study the direct transcriptional regulatory role of KMT2D, we established two endogenous N-terminus AID-KMT2D system in t human erythroblast cell lines and systematically investigated the effects of acute KMT2D loss by auxin-inducible degron system on transcriptional programs and chromatin accessibility. By integrating multi-omics datasets, we revealed that acute KMT2D loss notably suppressed the subset of GATA1 downstream targets. Importantly, we profiled the specific genome-wide occupancy of KMT2D by comparison between the presence and absence of KMT2D in AID model. Strikingly, KMT2D occupies over hundreds of erythroid specific genes mostly on their promoters. More importantly, we revealed that the KMT2D co-localized with GATA1 in numerous erythroid genes and the occupancy of GATA1 significantly reduced after KMT2D degradation. These results suggest KMT2D is indispensable for the enhancer-binding of GATA1 in gene expression in erythroid lineage specification.