An ongoing limitation of the Yamanaka method, notes Blelloch, is that it requires viral-mediated integration of four foreign genes so-called transgenes. The goal would be to add the genes only temporarily, or to use chemical compounds that could mimic the effect of the genes in the cells. This will be a key focus of ongoing studies, he says.
The biggest hurdle, of course, says Ramalho-Santos, will be translating the methods from the mouse to human cells, a process that could take years. Researchers around the world, including Ramalho-Santos, Blelloch and Yamanaka, are working intently on this challenge.
Its a very exciting time in stem cell biology, as exemplified in the studies of reprogramming, says Ramalho-Santos. Its fascinating enough that an embryonic stem cell can give rise to all cell types of the body. But thats what embryonic stem cells do. They grow and in the end give rise to the whole organism.
But taking back a differentiated cell to the embryonic stem cell state thats truly mesmerizing. It goes against the flow of development -- and yet we can do it. And were getting easier technical ways to do it.
|Contact: Jennifer O'Brien|
University of California - San Francisco