Directly reprogrammed fibroblasts show global epigenetic remodeling and widespread tissue contribution.
Ectopic expression of the four transcription factors Oct4, Sox2, c-Myc, and Klf4 is sufficient to confer a pluripotent state upon the fibroblast genome, generating induced pluripotent stem (iPS) cells. It remains unknown if nuclear reprogramming induced by these four factors globally resets epigenetic differences between differentiated and pluripotent cells. Here, using novel selection approaches, we have generated iPS cells from fibroblasts to characterize their epigenetic state. Female iPS cells showed reactivation of a somatically silenced X chromosome and underwent random X inactivation upon differentiation. Genome-wide analysis of two key histone modifications indicated that iPS cells are highly similar to ES cells. Consistent with these observations, iPS cells gave rise to viable high-degree chimeras with contribution to the germline. These data show that transcription factor-induced reprogramming leads to the global reversion of the somatic epigenome into an ES-like state. Our results provide a paradigm for studying the epigenetic modifications that accompany nuclear reprogramming and suggest that abnormal epigenetic reprogramming does not pose a problem for the potential therapeutic applications of iPS cells.
Maherali
Nimet
N
Massachusetts General Hospital Cancer Center and Center for Regenerative Medicine, Harvard Stem Cell Institute, 185 Cambridge Street, Boston, MA 02114, USA; Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.
Sridharan
Rupa
R
Department of Biological Chemistry, Johnson Comprehensive Cancer Center and Institute for Stem Cell Biology and Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Xie
Wei
W
Department of Biological Chemistry, Johnson Comprehensive Cancer Center and Institute for Stem Cell Biology and Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Utikal
Jochen
J
Massachusetts General Hospital Cancer Center and Center for Regenerative Medicine, Harvard Stem Cell Institute, 185 Cambridge Street, Boston, MA 02114, USA.
Eminli
Sarah
S
Massachusetts General Hospital Cancer Center and Center for Regenerative Medicine, Harvard Stem Cell Institute, 185 Cambridge Street, Boston, MA 02114, USA.
Arnold
Katrin
K
Massachusetts General Hospital Cancer Center and Center for Regenerative Medicine, Harvard Stem Cell Institute, 185 Cambridge Street, Boston, MA 02114, USA.
Stadtfeld
Matthias
M
Massachusetts General Hospital Cancer Center and Center for Regenerative Medicine, Harvard Stem Cell Institute, 185 Cambridge Street, Boston, MA 02114, USA.
Yachechko
Robin
R
Department of Biological Chemistry, Johnson Comprehensive Cancer Center and Institute for Stem Cell Biology and Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Tchieu
Jason
J
Department of Biological Chemistry, Johnson Comprehensive Cancer Center and Institute for Stem Cell Biology and Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Jaenisch
Rudolf
R
Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA.
Plath
Kathrin
K
Department of Biological Chemistry, Johnson Comprehensive Cancer Center and Institute for Stem Cell Biology and Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA; Molecular Biology Institute, Johnson Comprehensive Cancer Center and Institute for Stem Cell Biology and Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA. Electronic address: kplath@mednet.ucla.edu.
Hochedlinger
Konrad
K
Massachusetts General Hospital Cancer Center and Center for Regenerative Medicine, Harvard Stem Cell Institute, 185 Cambridge Street, Boston, MA 02114, USA. Electronic address: khochedlinger@helix.mgh.harvard.edu.
D000818:Animals; D002454:Cell Differentiation; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D005347:Fibroblasts / Q000166:cytology*; D000090062:Kruppel-Like Factor 4; D051379:Mice; D036103:Nanotechnology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism; D049951:X Chromosome Inactivation
C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D014157:Transcription Factors