HDAC1 and PRC2 mediate combinatorial control in SPI1/PU.1-dependent gene repression in murine erythroleukaemia

Abstract

Although originally described as transcriptional activator, SPI1/PU.1, a major player in haematopoiesis whose alterations are associated with haematological malignancies, has the ability to repress transcription. Here, we investigated the mechanisms underlying gene repression in the erythroid lineage, in which SPI1 exerts an oncogenic function by blocking differentiation. We show that SPI1 represses genes by binding active enhancers that are located in intergenic or gene body regions. HDAC1 acts as a cooperative mediator of SPI1-induced transcriptional repression by deacetylating SPI1-bound enhancers in a subset of genes, including those involved in erythroid differentiation. Enhancer deacetylation impacts on promoter acetylation, chromatin accessibility and RNA pol II occupancy. In addition to the activities of HDAC1, polycomb repressive complex 2 (PRC2) reinforces gene repression by depositing H3K27me3 at promoter sequences when SPI1 is located at enhancer sequences. Moreover, our study identified a synergistic relationship between PRC2 and HDAC1 complexes in mediating the transcriptional repression activity of SPI1, ultimately inducing synergistic adverse effects on leukaemic cell survival. Our results highlight the importance of the mechanism underlying transcriptional repression in leukemic cells, involving complex functional connections between SPI1 and the epigenetic regulators PRC2 and HDAC1.

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Enhancer remodeling drives MLL oncogene-dependent transcriptional dysregulation in leukemia stem cells

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A novel molecular class that recruits HDAC/MECP2 complexes to PU.1 motifs reduces neuroinflammation

“…3 e ). Pulldown of NONO ( Hallier et al, 1996 ) was reduced by ∼31% after A11 treatment (P = 0.0368), while the pulldown of MECP2 ( Gregoricchio et al, 2022 ; Hallier et al, 1996 ) was increased by ∼150% (P = 0.0050). We also saw an ∼266% increase in HDAC1 (P = 0.0012), an ∼267% increase in SIN3A (P = 0.0171) and an ∼124% increase in DNMT3A (P = 0.0358) pulldown.…”

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