Pluripotential reprogramming of the somatic genome in hybrid cells occurs with the first cell cycle.
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 (approximately 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.
Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany.
Dong Wook
DW
Han
Jeong Tae
JT
Do
Luca
L
Gentile
Martin
M
Stehling
Hoon Taek
HT
Lee
Hans R
HR
Schöler
D000818:Animals; D002453:Cell Cycle; D002459:Cell Fusion; D019175:DNA Methylation; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005260:Female; D005786:Gene Expression Regulation; D016678:Genome; D049452:Green Fluorescent Proteins / Q000235:genetics; D006822:Hybrid Cells / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics
D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins