Reprogramming Somatic Cells

 
There were three papers published this week that showed how to reprogram somatic cells so they could act like embryonic stem cells (Maherali et al., 2007; Okita et al., 2007; Wernig et al., 2007). The trick is to introduce genes for four different transcription factors into the somatic cells (e.g., skin cells). When the four transcription factors (Oct4, Sox2, c-Myc, and Klf4) are made they turn on genes in the somatic cell that cause it to reprogram and become competent to differentiate into any other type of cell, including germ cells.

The experiments were performed in mice and they are based on the work of Takahashi and Yamanaka (2006). The interesting thing about this experiment is that it achieves a goal that most scientists expected; namely, the ability to reprogram cells by changing the pattern of gene expression. This goal was achieved less than two years after Science magazine asked two so-called "fundamental" questions in their July 2005 issue [SCIENCE Questions: How Does a Single Somatic Cell Become a Whole Plant? and SCIENCE Questions: How Can a Skin Cell Become a Nerve Cell?]. What it reveals is that the editors of Science were out of touch with the scientific community. These were not significant questions. The solution was known it was just a matter of finding out which transcription factors were required.

Here's a short video where Rudi Jaenisch explains the significance of his work. I think it represents good science communication from a scientist. What do you think?

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Maherali, N., Sridharan, R., Xie, W., Utikal, J., Eminli, S., Arnold, K., Stadtfeld, M., Yachechko, R., Tchieu, J., Jaenisch, R., Plath, K. and Hochedlinger, K. (2007) Directly Reprogrammed Fibroblasts Show Global Epigenetic Remodeling and Widespread Tissue Contribution. Cell: Stem Cell 1: 55-70.

Okita, K., Ichisaka, T. and Yamanaka, S. (2007) Generation of germline-competent induced pluripotent stem cells. Nature advance online publication 6 June 2007 | doi:10.1038/nature05934

Takahashi, K. and Yamanaka, S. (2007) Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 126, 663–676.

Wernig, M., Meissner, A., Foreman, R., Brambrink, T., Ku, M., Hochedlinger, K., Bernstein, B.E. and Jaenisch, R. (2007) In vitro reprogramming of fibroblasts into a pluripotent ES-cell-like state. Nature advance online publication 6 June 2007 |doi:10.1038/nature05944

[Hat Tip: Alex Palazzo for the video [Rudy Jaenisch on Stem Cells] and for alerting us in advance to watch for exciting news]