The stem cell and cloning achievements behind the Nobel

The 2012 Nobel Prize in Physiology or Medicine went to two scientists who laid the groundwork for us to someday rebuild our bodies using tissues created from our own cells.
Written by Laura Shin, Contributor

On Monday, two scientists were awarded the Nobel Prize in Physiology or Medicine: John B. Gurdon of the University of Cambridge and Shinya Yamanaka of Kyoto University.

Their work led to some sensational scientific feats, such as the cloning of the sheep named Dolly.

Below is a summary of their major accomplishments which have formed some of the foundation for regenerative medicine, the as yet unfulfilled quest to "[rebuild] the body with tissues generated from its own cells," as The New York Times puts it.

Dr. Gurdon's discoveries

What he did: In 1962, Dr. Gurdon created living tadpoles using adult frog cells. His feat was met with skepticism at the time, because until then, the definition of adult cells were cells that had specific functions and could not take on new ones.

How he did it: He extracted a cell nucleus from a mature intestinal cell and injected it into a frog egg whose nucleus had been removed. Because the nucleus he injected contained the frog's DNA, the egg was able to switch its genes so they no longer functioned as an intestinal cell and instead took on the duties of a developing egg.

Dr. Yamanaka advances the work

What he did: At the time of Dr. Gurdon's feat, no one understood how the adult cell reprogrammed itself. But 44 years later, in 2006, Dr. Yamanaka discovered the four gene agents that control reprogramming in the egg. These agents, called transcription factors, "are proteins made by master genes to regulate other genes," in the words of the Times.

How he did it: Dr. Yamanaka injected them into an adult cell and showed that he could then guide it back to its stem cell form, creating what is known as an induced pluripotent cell, or iPS cell.

Why it matters: Pluripotent cells are stem cells that can give rise to all cell types, while adult stem cells are generally limited in the types of tissues they can become, for instance skeletal vs. neural. Pluripotent cells have much greater medical potential.

Biologists are working on using the technique to create replacement tissues from a patient's own cells to protect against degenerative diseases -- for now, still far from reality.

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via: The New York Times

photo: tadpole (Brian Gratwicke/Wikimedia)

This post was originally published on Smartplanet.com

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