The magic of four： induction of pluripotent stem cells from somatic cells by Oct4, Sox2, Myc and Klf4

The developmental process from a fertilized egg to agrown adult is programmed with remarkable accuracy.While the genetic information of the fertilized egg and itsdescendent somatic cells are the same, it is the selectiveexpressions of the same genome that give rise to the 200or so different cell types in an adult. The differentiatedstates of these adult cells are maintained epigenetically,presumably through the modification of chromatins and theassociated histones. In higher mammals, it was thought thatthe differentiation process is irreversible until the successfulcloning of Dolly 1]. By transferring a nucleus from a fullydifferentiated cell in the mammary gland, Wilmut and col-leagues were able to generate an exact replica of a highermammal, the Doily 1]. This work not only demonstratedthat the genome of differentiated cells can be reprogrammedinto an embryonic state and then to resume a full-fledgeddevelopmental process to generate a normal adult, but alsorejuvenated the field of animal cloning. The prospect thata somatic cell from a patient may be reprogrammed to the

The magic of four: induction of pluripotent stem cells from somatic cells by Oct4, Sox2, Myc and Klf4

The developmental process from a fertilized egg to a grown adult is programmed with remarkable accuracy. While the genetic information of the fertilized egg and its descendent somatic cells are the same, it is the selective expressions of the same genome that give rise to the 200 or so different cell types in an adult.