MIT Researchers Show That iPS Cells Are Fully Pluripotent Friday, 29 February 2008 In this month's issue of Cell Stem Cell, scientists at MIT's Whitehead Institute for Biomedical Research continue their groundbreaking work on pluripotent stem cells. The team headed by Rudolf Jaenisch shows that a specific sequence of biochemical manipulations can reprogram a skin cell into a pluripotent stem cell. Results showed that when expressing the reprogramming genes, a minimum of 16 days is required to fully reprogram skin cells to pluripotent cells, with one pluripotency marker arising first at three days, followed by another marker at nine days, and the fully reprogrammed cell at 16 days or later. This final stage of reprogramming was also the time in which the expression of the four genes could be removed. Any time point before then, the cells could not be reprogrammed. The cells thus go through a sequential, not random, process of reprogramming. Jaenisch concludes that there is a specific sequence of events required for reprogramming a cell to a pluripotent state. Also, silencing of the four reprogramming genes is necessary for differentiation of the iPS. The results will help future researchers to define what a cell needs to reprogram itself without using a virus or cancer-causing genes.
Sequential Expression of Pluripotency Markers during Direct Reprogramming of Mouse Somatic Cells
Cell Stem Cell, Vol 2, 151-159, 07 February 2008
For more on stem cells and cloning, go to CellNEWS at http://www.geocities.com/giantfideli/index.html