From left: John Gurdon, Shinya Yamanaka. Image taken from Nobelprize.org
The Nobel Prize in Physiology and Medicine for the year 2012 is jointly awarded to John B. Gurdon of University of Cambridge and Shinya Yamanaka of Kyoto University.
What is it awarded for?
The citation of the award was "for the discovery that mature cells can be reprogrammed to become pluripotent".
In 1962, working with frog eggs, John Gurdon discovered that nuclei of somatic cells contained all required information to develop into a mature organism. In a classic experiment, he replaced an immature nucleus from a frog egg with a nucleus from a mature intestinal cell. The modified egg cell develops into a normal tadpole.
More than 40 years later, Shinya Yamanaka showed that intact, mature cells can be turned into stem cells by introducing a few genes. These stem cells are able to develop into all cell types of the body.
Image taken from Nobelprize.org
What is the impact of the discovery?
All of us begins our life in the womb as a single cell. From this cell known as zygote, it keeps dividing and give rise to over 300 cell types in the body. This single cell develops into organs found in pregnacy (including the embryo), known as totipotency. Pluripotency is the ability to become all cell types except the placenta and amniotic sac.
We have traditionally thought that differentiation into mature cells is irreversible. The former discovery challenged this understanding, showing that the genetic program for cell differentiation is not lost as the organism develops but retained throughout the organism's lifetime. The latter discovery took one step further, showing genetic programs required to maintain the pluripotent state of stem cells.
The discoveries resolved the ethical controversy of working with embryonic stem cells and also opens up new avenues to treating diseases using the approach of regenerative medicine, including:
- Creating reprogrammed pluripotent stem cells to treat blood cancer
- Inducing cell division of nerve cells to treat paralysis
- Creating "disease in a dish" model to study diseases from a developmental biology approach
Advanced Information (if you understand biology)