Requirement of Nanog dimerization for stem cell self-renewal and pluripotency
- *Division of Hematology-Oncology, Children's Hospital and Dana Farber Cancer Institute, Harvard Medical School, Harvard Stem Cell Institute, and
- †Howard Hughes Medical Institute, Boston, MA 02115
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Contributed by Stuart H. Orkin, March 6, 2008 (received for review February 29, 2008)
Abstract
Pluripotency of embryonic stem (ES) cells is maintained by transcription factors that form a highly interconnected protein interaction network surrounding the homeobox protein Nanog. Enforced expression of Nanog in mouse ES (mES) cells promotes self-renewal and alleviates their requirement for leukemia inhibitory factor (LIF). Understanding molecular mechanisms by which Nanog functions should illuminate fundamental properties of stem cells and the process of cellular reprogramming. Previously, we showed that Nanog forms multiple protein complexes in mES cells. Here, we demonstrate that Nanog dimerizes through its C-terminal domain rather than the homeodomain. Dimerization is required for interaction with other pluripotency network proteins. We also show that enforced expression of the Nanog dimer, but not the monomer, functionally replaces wild-type Nanog to sustain LIF-independent self-renewal of ES cells. Our results demonstrate that Nanog–Nanog homodimerization is a critical aspect of its function promoting stem cell pluripotency.
Footnotes
- ‡To whom correspondence should be addressed. E-mail: orkin{at}bloodgroup.tch.harvard.edu
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Author contributions: J.W. and S.H.O. designed research; J.W. and D.N.L. performed research; J.W. analyzed data; and J.W. and S.H.O. wrote the paper.
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The authors declare no conflict of interest.
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This article contains supporting information online at www.pnas.org/cgi/content/full/0802288105/DCSupplemental.
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Freely available online through the PNAS open access option.
- © 2008 by The National Academy of Sciences of the USA
