A Genome Scale CRISPR Screen Identifies Novel Genes That Regulate Erythropoietin Production

Erythropoietin (EPO) is a plasma glycoprotein that binds bone marrow erythroid progenitors, stimulating their proliferation and differentiation. EPO is secreted into the circulation by hepatocytes and specialized kidney peritubular fibroblasts, which contribute ~20% and ~80% of the total plasma EPO level, respectively. EPO production is induced during hypoxia, due to enhanced stability of the transcription factor hypoxia-inducible factor (HIF). However, increased HIF activity results in enhanced expression of angiogenesis and oncogenesis promoting genes, raising concerns about clinical strategies that promote EPO production via increasing HIF levels.