iPS on the Way

Two teams report creating mice from iPS cells. In Nature, researchers led by the Chinese Academy of Sciences' Qi Zhou followed Kyoto University's Shinya Yamanaka's protocol and used viral vectors to introduce four factors into mouse fibroblast cells to reprogram them. Zhou's group was able to get 27 live mouse births with their best method getting 22 live births at a success rate of 3.5 percent. In Cell Stem Cell, National Institute of Biological Sciences in Beijing's Shaorong Gao's team used a similar technique to yield two live births at 1.1 percent success rate, though one died soon thereafter. "They have shown that iPS cells can satisfy the most stringent criteria of pluripotency," Harvard's George Daley says in Wired. His colleague Konrad Hochedlinger adds in the Washington Post that "this clearly says for the first time that iPS cells pass the most stringent test." However, this doesn't mean that iPS cells are identical to embryonic stem cells. "Here's another way in which these cells are functionally similar to [embryonic stem cells], but it's not to say that they're identical," University of Michigan's Sean Morrison says, also in Wired.