So the Nobel Prize in Physiology and Medicine for 2012 has been announced, but what have the deserving winners done anyway? Here’s a look at the defining achievements that have cemented their place in history.
What’s the Big Deal With Stem Cells?
Sir John Gurdon from Cambridge and Dr. Shinya Yamanaka from Kyoto University have won the prize for their work on induced pluripotent stem cells (IPS), and every biologist has greeted this news with a cheer. Every cell in our body is specialized to perform its own task; that’s why your food goes into your stomach and air into your lungs. However, every cell in our body arises from one single cell. How does this division of labor occur? At some stage of development in the womb, cells undergo a process called ‘differentiation’, which is what tells the cells what functions they will be restricted to performing. What we call ‘stem cells’ are essentially undifferentiated cells, which are enormously powerful simply because they can turn into any type of tissue we want!
This differentiation was thought to be one-directional. In 1962, Sir John Gurdon showed that the reverse of the ‘differentiation’ process could be achieved. Cells from a tissue like the skin could be reversed to form ‘stem cells’ that could in turn turn into any type of tissue. He took out the nucleus of an adult frog and injected it into an egg cell of a tadpole (from which the DNA-containing nucleus had been removed). This embryo then grew into a live tadpole, showing that ‘adult DNA’ really could become ‘immature’ again.
Dr. Shinya Yamanaka, in 2006, concocted an actual recipe for this reverse differentiation, and produced IPS cells from the skin cells of mice in this seminal paper. He identified 4 genes that could convert these skin cells into immature yet all-powerful stem cells.
These cells have huge potential in both medicine and research. Brain cells, for example, are notoriously difficult to isolate. Thanks to their discovery, we can produce IPS cells and culture brain cells instead of having to isolate them. While the direct applications to medicine are not yet on the horizon, this technology does hold promises for the future.