shRNA Knockdown of Bmi-1 Reveals a Critical Role for p21-Rb Pathway in NSC Self-Renewal during Development

Christopher A. Fasano, John T. Dimos, Natalia B. Ivanova, Natalia Lowry, Ihor R. Lemischka, Sally Temple

    Research output: Contribution to journalArticlepeer-review


    Knockout studies have shown that the polycomb gene Bmi-1 is important for postnatal, but not embryonic, neural stem cell (NSC) self-renewal and have identified the cell-cycle inhibitors p16/p19 as molecular targets. Here, using lentiviral-delivered shRNAs in vitro and in vivo, we determined that Bmi-1 is also important for NSC self-renewal in the embryo. We found that neural progenitors depend increasingly on Bmi-1 for proliferation as development proceeds from embryonic through adult stages. Acute shRNA-mediated Bmi-1 reduction causes defects in embryonic and adult NSC proliferation and self-renewal that, unexpectedly, are mediated by a different cell-cycle inhibitor, p21. Gene array analyses revealed developmental differences in Bmi-1-controlled expression of genes in the p21-Rb cell cycle regulatory pathway. Our data therefore implicate p21 as an important Bmi-1 target in NSCs, potentially with stage-related differences. Understanding stage-related mechanisms underlying NSC self-renewal has important implications for development of stem cell-based therapies. © 2007 Elsevier Inc. All rights reserved.
    Original languageEnglish
    Pages (from-to)87-99
    Number of pages12
    JournalCell Stem Cell
    Issue number1
    Publication statusPublished - 7 Jun 2007




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