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Friday, June 08, 2007

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?



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]

8 comments :

  1. Herr Jaenisch communicated without benefit of the framing science clergy? Does this mean that framing science is on the skids?

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  2. I thought he communicated very well, yes.

    I understood all (I think) of the jargon he used. I don't know how well a person with very little biology background would be able to follow what he said, but I suspect the key message would still get through just fine. That is, that this is exciting and interesting work, so far conducted only on mice but with strong potential for human applications with more work required. Good stuff.

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  3. Unfortunately, my connection is currently so slow that I could only watch parts of the video. However, I’ve listened to talks of Rudi Jaenisch on two meetings and I must admit that he does some real clever research. And he did this for years, e.g. he not only was one of the first who generated completely ES-cell derived mice by using tetraploid ES-cells as blastocysts. More importantly, he did quite some cool stuff on imprinting and X-inactivation to explain why F1 ES-cells can be used for this purpose and ES-cells derived from inbred strains don’t work in this respect (the later issue has recently been solved through ES-cell injection in 2-8 cell embryos). So, he is not just one of these tech guys who try to advances technologies but someone who asks the real questions. In addition, he can present his answers in a way that you get the impression he is presenting some easy stuff from a textbook because everything he presents is logically linked so that you can really follow him. If you ever get the chance to listen to one of his talks, don’t miss it.

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  4. Martin says,

    If you ever get the chance to listen to one of his talks, don’t miss it.

    I know Rudi. He was a post-doc in Janet Rossant's lab here in Toronto at a time when she and I were publishing papers together. That's where he learned to clone mice using ES cells.

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  5. In addition, he can present his answers in a way that you get the impression he is presenting some easy stuff from a textbook because everything he presents is logically linked so that you can really follow him.

    Yes, that's the feeling I had watching that video. He made it seem like all the problems that had been solved in this field in the last year or two were actually common knowledge and had been solved decades ago. I wish I could communicate that well.

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  6. August Weizmann must be turning in his grave.

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  7. Larry, I don't believe it is accurate to say that Rudi was Janet Rossant's postdoc (he did his postdoctoral work with Bea Mintz in the 70's). Rudi may have spent time with Janet acquiring techniques, but that is different from being her postdoc.

    BTW, I was Rudi's postdoc from '86 to '89. He just as brilliant and personable as the video would suggest.

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  8. Anonymous says,

    Larry, I don't believe it is accurate to say that Rudi was Janet Rossant's postdoc (he did his postdoctoral work with Bea Mintz in the 70's). Rudi may have spent time with Janet acquiring techniques, but that is different from being her postdoc.

    Thanks. I stand corrected. Now you've got me wondering how long he was here or whether I just imagined imagined that he was in Janet's lab. :-)

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