The Polycomb-associated factor PHF19 controls hematopoietic stem cell state and differentiation.

Vizán, Pedro; Gutiérrez, Arantxa; Espejo, Isabel; García-Montolio, Marc; Lange, Martin; Carretero, Ana; Lafzi, Atefeh; de Andrés-Aguayo, Luisa et al. · Sci Adv · 2020

basic_science · Level V

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Abstract

Adult hematopoietic stem cells (HSCs) are rare multipotent cells in bone marrow that are responsible for generating all blood cell types. HSCs are a heterogeneous group of cells with high plasticity, in part, conferred by epigenetic mechanisms. PHF19, a subunit of the Polycomb repressive complex 2 (PRC2), is preferentially expressed in mouse hematopoietic precursors. Here, we now show that, in stark contrast to results published for other PRC2 subunits, genetic depletion of <i>Phf19</i> increases HSC identity and quiescence. While proliferation of HSCs is normally triggered by forced mobilization, defects in differentiation impede long-term correct blood production, eventually leading to aberrant hematopoiesis. At molecular level, PHF19 deletion triggers a redistribution of the histone repressive mark H3K27me3, which notably accumulates at blood lineage-specific genes. Our results provide novel insights into how epigenetic mechanisms determine HSC identity, control differentiation, and are key for proper hematopoiesis.