The potential for transplant medicine was immediately recognized, as was their promise as a window to the earliest stages of human development, and for novel drug discovery schemes. The capacity to generate cells that could be used to treat diseases such as Parkinson's, diabetes and spinal cord injuries, among others, garnered much interest by patients and patient advocacy groups.
But embryonic stem cells also sparked significant controversy as embryos were destroyed in the process of obtaining them, and they became a potent national political issue beginning with the 2000 presidential campaign. Since 2001, a national policy has permitted only limited use of some embryonic stem cell lines by scientists receiving public funding.
In the new study, to induce the skin cells to what scientists call a pluripotent state, a condition that is essentially the same as that of embryonic stem cells, Yu, Thomson and their colleagues introduced a set of four genes into human fibroblasts, skin cells that are easy to obtain and grow in culture.
Finding a combination of genes capable of transforming differentiated skin cells to undifferentiated stem cells helps resolve a critical question posed by Dolly, the famous sheep cloned in 1996. Dolly was the result of the nucleus of an adult cell transferred to an oocyte, an unfertilized egg. An unknown combination of factors in the egg caused the adult cell nucleus to be reprogrammed and, when implanted in a surrogate mother, develop into a fully formed animal.
The new study by Yu and Thomson reveal some of those genetic factors. The ability to reprogram human cells through well defined factors would permit the generation of patient-specific stem cell lines without use of the cloning techniques employed by the
|Contact: Terry Devitt|
University of Wisconsin-Madison