All-iPS cell mice generated from terminally differentiated B cells

The generation of induced pluripotent stem cells (iPSCs) often results in aberrant silencing of the imprinted Dlk1-Dio3 gene cluster, which compromises their ability to generate entirely iPSC-derived mice (all-iPSC mice). Here, we show that reprogramming in the presence of ascorbic acid attenuates hypermethylation of Dlk1-Dio3 by enabling a chromatin configuration at its imprint control region that interferes with abnormal binding of the DNA methyltransferase Dnmt3a. This approach allowed us to generate adult all-iPSC mice from mature B cells, which have thus far failed to support the development of exclusively iPSC-derived postnatal mice. Our data demonstrate that factor-mediated reprogramming can endow a defined, terminally differentiated cell type with a developmental potential equivalent to that of embryonic stem cells. More generally, these findings indicate that the choice of culture conditions used for transcription factor-mediated reprogramming can strongly influence the epigenetic and biological properties of resultant iPSCs.

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