Role of the polycomb group proteins in hematopoietic stem cells

Authors

  • Takaaki Konuma,

    1. Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670
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  • Hideyuki Oguro,

    1. Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670
    2. JST, CREST, Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
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  • Atsushi Iwama

    Corresponding author
    1. Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670
    2. JST, CREST, Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
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Author to whom all correspondence should be addressed.
Email: aiwama@faculty.chiba-u.jp

Abstract

Polycomb group (PcG) proteins play a role in the transcriptional repression of genes through histone modifications. Recent studies have clearly demonstrated that PcG proteins are required for the maintenance of embryonic as well as a broad range of adult stem cells, including hematopoietic stem cells (HSCs). PcG proteins maintain the self-renewal capacity of HSCs by repressing tumor suppressor genes and keep differentiation programs poised for activation in HSCs by repressing a cohort of hematopoietic developmental regulator genes via bivalent chromatin domains. Enforced expression of one of the PcG genes, Bmi1, augments the self-renewal capacity of HSCs. PcG proteins also maintain redox homeostasis to prevent premature loss of HSCs. These findings established PcG proteins as essential regulators of HSCs and underscored epigenetics as a new field of HSC research. In this review, we focus on the role of PcG proteins in the epigenetic regulation of the self-renewal capacity and multipotency of HSCs.

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