Singapore: Dr Shinya Yamanaka, director of the Center for iPS Cell Research and Application (CiRA), Kyoto University, has won the Nobel Prize in Physiology or Medicine along with British researcher Sir John B Gurdon for the discovery of that mature cells can be reprogrammed to become pluripotent. This finding is believed to have revolutionized the understanding of how cells and organisms develop.

The discoveries of Sir Gurdon and Dr Yamanaka have shown that specialized cells can turn back the developmental clock under certain circumstances. Although their genome undergoes modifications during development, these modifications are not irreversible.

The Nobel citation mentions that Sir John B Gurdon discovered in 1962 that the specialisation of cells is reversible. In a classic experiment, he replaced the immature cell nucleus in an egg cell of a frog with the nucleus from a mature intestinal cell. This modified egg cell developed into a normal tadpole. The DNA of the mature cell still had all the information needed to develop all cells in the frog.

Dr Shinya Yamanaka discovered more than 40 years later, in 2006, how intact mature cells in mice could be reprogrammed to become immature stem cells. Surprisingly, by introducing only a few genes, he could reprogram mature cells to become pluripotent stem cells, ie immature cells that are able to develop into all types of cells in the body.

"These groundbreaking discoveries have completely changed our view of the development and cellular specialisation. We now understand that the mature cell does not have to be confined forever to its specialised state. Textbooks have been rewritten and new research fields have been established. By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy," the official Nobel Prize website said.