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This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 2007-0951v1 26/4/903    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints/Permissions Google Scholar Articles by Kopp, J. L. Articles by Rizzino, A. PubMed PubMed Citation Articles by Kopp, J. L. Articles by Rizzino, A.

EMBRYONIC STEM CELLS

Small Increases in the Level of Sox2 Trigger the Differentiation of Mouse Embryonic Stem Cells

^aEppley Institute for Research in Cancer and Allied Diseases and
Departments of ^bPathology and Microbiology
^cBiochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA

Key Words. Development • Embryogenesis • Fgf-4 • Oct-3/4 • Nanog • Neuroectoderm • Trophectoderm • Mesoderm

Correspondence: Angie Rizzino, Ph.D., 986805 Nebraska Medical Center, Omaha, Nebraska 68198, USA. Telephone: 402-559-6338; Fax: 402-559-3339; e-mail: arizzino{at}unmc.edu

Received November 13, 2007; accepted for publication January 23, 2008.
First published online in STEM CELLS EXPRESS   January 31, 2008.



Previous studies have demonstrated that the transcription factor Sox2 is essential during the early stages of development. Furthermore, decreasing the expression of Sox2 severely interferes with the self-renewal and pluripotency of embryonic stem (ES) cells. Other studies have shown that Sox2, in conjunction with the transcription factor Oct-3/4, stimulates its own transcription as well as the expression of a growing list of genes (Sox2:Oct-3/4 target genes) that require the cooperative action of Sox2 and Oct-3/4. Remarkably, recent studies have shown that overexpression of Sox2 decreases expression of its own gene, as well as four other Sox2:Oct-3/4 target genes (Oct-3/4, Nanog, Fgf-4, and Utf1). This finding led to the prediction that overexpression of Sox2 in ES cells would trigger their differentiation. In the current study, we initially engineered mouse ES cells for inducible overexpression of Sox2. Using this model system, we demonstrate that small increases (twofold or less) in Sox2 protein trigger the differentiation of ES cells into cells that exhibit markers for a wide range of differentiated cell types, including neuroectoderm, mesoderm, and trophectoderm but not endoderm. We also demonstrate that elevating the levels of Sox2 quickly downregulates several developmentally regulated genes, including Nanog, and a newly identified Sox2:Oct-3/4 target gene, Lefty1. Together, these data argue that the self-renewal of ES cells requires that Sox2 levels be maintained within narrow limits. Thus, Sox2 appears to function as a molecular rheostat that controls the expression of a critical set of embryonic genes, as well as the self-renewal and differentiation of ES cells.

Disclosure of potential conflicts of interest is found at the end of this article.