HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 2007-0553v1 26/2/445    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 Han, D. W. Articles by Schöler, H. R. PubMed PubMed Citation Articles by Han, D. W. Articles by Schöler, H. R.

EMBRYONIC STEM CELLS

Pluripotential Reprogramming of the Somatic Genome in Hybrid Cells Occurs with the First Cell Cycle

^aDepartment of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany;
^bDepartment of Bioscience and Biotechnology, Bio-Organ Research Center, Konkuk University, Seoul, South Korea

Key Words. Oct4 • Reprogramming • Fusion • DNA methylation • Cell cycle

Correspondence: Hans R. Schöler, Ph.D., Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany. Telephone: 49-251-70365-300; Fax: 49-251-70365-399; e-mail: schoeler{at}mpi-muenster.mpg.de

Received July 11, 2007; accepted for publication November 19, 2007.
First published online in STEM CELLS EXPRESS   December 6, 2007.



The fusion of pluripotent embryonic cells with somatic cells results in reprogramming of the somatic cell genome. Oct4-green fluorescent protein (GFP) transgenes that do not contain the proximal enhancer (PE) region are widely used to visualize reprogramming of the somatic to the pluripotent cell state. The temporal onset of Oct4-GFP activation has been found to occur 40–48 hours postfusion. We asked whether activation of the transgene actually reflects activation of the endogenous Oct4 gene. In the current study, we show that activation of an Oct4-GFP transgene that contains the PE region occurs within 22 hours of fusion. In addition, demethylation of the Oct4-GFP transgene and that of the endogenous Oct4 and Nanog genes was found to occur within 24 hours of fusion. As this timing corresponds with the timing of cell cycle completion in embryonic stem cells and fusion hybrids (22 hours), we postulate that pluripotential reprogramming of the somatic cell genome begins during the first cell cycle after the fusion of a somatic cell with a pluripotent cell and has been completed by day 2 postfusion.

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