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Updated: Feb 7, 2026

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells iPSCs Using Retroviral Vector with GFP
Published on: April 3, 2012
Prospective Isolation of Poised iPSC Intermediates Reveals Principles of Cellular Reprogramming
Benjamin A Schwarz1, Murat Cetinbas2, Kendell Clement3
1Department of Molecular Biology, Cancer Center, and Center for Regenerative Medicine, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA; Harvard Stem Cell Institute, 1350 Massachusetts Avenue, Cambridge, MA 02138, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Department of Pathology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.
Abstract:
Cellular reprogramming converts differentiated cells into induced pluripotent stem cells (iPSCs). However, this process is typically very inefficient, complicating mechanistic studies. We identified and molecularly characterized rare, early intermediates poised to reprogram with up to 95% efficiency, without perturbing additional genes or pathways, during iPSC generation from mouse embryonic fibroblasts. Analysis of these cells uncovered transcription factors (e.g., Tfap2c and Bex2) that are important for reprogramming but dispensable for pluripotency maintenance. Additionally, we observed striking patterns of chromatin hyperaccessibility at pluripotency loci, which preceded gene expression in poised intermediates. Finally, inspection of these hyperaccessible regions revealed an early wave of DNA demethylation that is uncoupled from de novo methylation of somatic regions late in reprogramming. Our study underscores the importance of investigating rare intermediates poised to produce iPSCs, provides insights into reprogramming mechanisms, and offers a valuable resource for the dissection of transcriptional and epigenetic dynamics intrinsic to cell fate change.
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