Gene Regulatory Networks Mediating Canonical Wnt Signal-Directed Control of Pluripotency and Differentiation in Embryo Stem Cells

Authors

  • Xiaoxiao Zhang,

    1. Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA
    2. Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
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  • Kevin A. Peterson,

    1. Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA
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  • X. Shirley Liu,

    1. Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Harvard School of Public Health, Boston, Massachusetts, USA
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  • Andrew P. McMahon,

    Corresponding author
    1. Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA
    2. Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
    3. Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
    • Department of Stem Cell Biology and Regenerative Medicine, Broad-CIRM Center, W.M. Keck School of Medicine, University of Southern California, California 90089, USA. E-mail: amcmahon@med.usc.edu Telephone: +1-323-442-3056; Fax: +1-323-442-8024

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  • Shinsuke Ohba

    1. Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA
    2. Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, The University of Tokyo Graduate School of Medicine, Tokyo, Japan
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  • Author contributions: X.Z. and S.O.: conception and design, collection and/or assembly of data, data analysis and interpretation, and manuscript writing; K.A.P.: collection and/or assembly of data and data analysis and interpretation; X.S.L.: data analysis and interpretation; A.P.M.: conception and design, data analysis and interpretation, financial support, manuscript writing, and final approval of manuscript. X.Z. and S.O. contributed equally to this article.

Abstract

Canonical Wnt signaling supports the pluripotency of embryonic stem cells (ESCs) but also promotes differentiation of early mammalian cell lineages. To explain these paradoxical observations, we explored the gene regulatory networks at play. Canonical Wnt signaling is intertwined with the pluripotency network comprising Nanog, Oct4, and Sox2 in mouse ESCs. In defined media supporting the derivation and propagation of ESCs, Tcf3 and β-catenin interact with Oct4; Tcf3 binds to Sox motif within Oct-Sox composite motifs that are also bound by Oct4-Sox2 complexes. Furthermore, canonical Wnt signaling upregulates the activity of the Pou5f1 distal enhancer via the Sox motif in ESCs. When viewed in the context of published studies on Tcf3 and β-catenin mutants, our findings suggest Tcf3 counters pluripotency by competition with Sox2 at these sites, and Tcf3 inhibition is blocked by β-catenin entry into this complex. Wnt pathway stimulation also triggers β-catenin association at regulatory elements with classic Lef/Tcf motifs associated with differentiation programs. The failure to activate these targets in the presence of a mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor essential for ESC culture suggests MEK/ERK signaling and canonical Wnt signaling combine to promote ESC differentiation. Stem Cells 2013;31:2667–2679

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