Distinct contributions of KAT2A histone acetyl-transferase complexes to human erythropoiesis [RNA-seq]

KAT2A is a histone acetyl-transferase involved in stabilization of transcriptional activity through acetylation of lysine residue 9 of Histone 3. Mouse knockout models suggest that Kat2a is dispensable for haematopoietic stem and progenitor cell activity, despite a central role in survival and maintenance of Acute Myekoid Leukaemia cells through block of differentiation. Herein, we investigate KAT2A activity in human cord blood haematopoiesis and identify a specific requirement in the establishment of the erythroid lineage. KAT2A is required for specification and survival of Erythroid-Megakaryocytic progenitors, with regulation of expression of the erythropoietin receptor (EPOR) gene, which participates in lineage commitment, as well as of later effector genes in the platelet and erythroid lineages. Early and late lineage roles can be distinctly attributed to the ATAC and SAGA complexes in which context KAT2A exerts its activity. ATAC is active earlier in erythroid lineage development and mediates MEP specification from HSC, whilst SAGA activity is required post-commitment, including in expression of haemoglobin genes. We thus position KAT2A as a novel regulator of human erythropoiesis and separate early and later effects in lineage development with complex specificity. This has implications for putative therapeutic targeting of KAT2A complexes in leukaemia. Overall design: 2 individual cord blood samples treated as independent biological replicates were enriched for CD34+ haematopoietic stem cells (HSC) and progenitors by magnetic selection using the StemCell Technologies EasySep system. CD34+ cells from each cord blood sample were transduced with lentiviral vectors (LV) encoding a control non-targeting shRNA or a shRNA directed at KAT2A, as well as reporter GFP gene. Four days after LV transduction, cells were sorted by flow cytometry on the basis of GFP expression, coupled with CD34+ CD38- CD45RA- staining to isolate HSC and multipotent progenitors expressing the shRNA of interest. KAT2A knockdown on the paired samples was confirmed by qRT-PCR prior to library preparation.