This is so cool!

Induced Pluripotent Stem Cells are usually engineered with genes to become embryonic stem cells. However, some enterprising people have taken the proteins encoded by the four genes (c-Myc, Klf4, Oct4 and Sox2) that are typically used to reprogram cells. They placed a eleven-amino acid tag on the front of the protein that helped them pass through the cell membrane. Then they soaked mouse fibroblast cells in a solution that contained these proteins plus a chemical called valproic acid. This reprogrammed the cells so that they were “morphologically indistinguishable” from embryonic stem cells and expressed similar markers.

Thus they were able to make protein-induced pluripotent stem cells (piPSCs) with no genetic engineering.  No embryos were killed in this process.


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Professor of Biochemistry at Spring Arbor University (SAU) in Spring Arbor, MI. Have been at SAU since 1999. Author of The Stem Cell Epistles. Before that I was a postdoctoral research fellow at the University of Pennsylvania in Philadelphia, PA (1997-1999), and Sussex University, Falmer, UK (1994-1997). I studied Cell and Developmental Biology at UC Irvine (PhD 1994), and Microbiology at UC Davis (MA 1986, BS 1984).