In 2012, Dr. John Gurdon and Dr. Shinya Yamanaka received the Nobel Prize in Physiology or Medicine “for the discovery that mature cells can be reprogrammed to become pluripotent.” Sir John Gurdon had shown that the cytoplasm of the oocyte can reprogram the expression of genes coming from the nucleus of a somatic cell. This was surprising, in that gene expression is usually associated with the nucleus telling the cytoplasm what to do. However, Gurdon, and others (see below) demonstrated that the cytoplasm can regulate gene expression. Moreover, the oocyte cytoplasm can activate the earliest genes in amphibian development. A nucleus from a larval somatic cell (say, an intestinal cell), when transferred into an activated enucleated from egg, can generate an adult frog. His Nobel Lecture, “The Egg and the Nucleus: A Battle for Supremacy,” can be heard at:
http://www.nobelprize.org/nobel_prizes/medicine/laureates/2012/gurdon-lecture.html
Dr. Yamanaka showed that when the genes associated with early development are activated in differentiated mammalian somatic cells, the cells revert to the stage of embryonic stem cells—cells of the early mammalian embryo that are capable of forming every cell type in the body. This topic will be discussed in pages 328–331 of the textbook. This ability to make a stem cell from any cell of the body (“induced pluripotent stem cells”) opens an area of regenerative medicine that may enable the replacement of diseased body parts. Dr. Yamanaka’s lecture, “The Winding Road to Pluripotency” can be heard at:
http://www.nobelprize.org/mediaplayer/index.php?id=1866
The research of Dr. Yamanaka and Dr. Gurdon demonstrated that all the genes were still present in the differentiated cells. It also showed that the genes present in the nuclei of differentiated cells could be restored to a pluripotent condition (that is, a condition capable of generating every cell in the body) by factors active in the oocyte cytoplasm (Gurdon) or by transcription factors added to the nucleus (mammals). Interestingly, both men had been told at various times in their career that they would never succeed in science.
For the New York Times announcement of the award, see: