This article is reproduced with the permission of New Scientist for exclusive use by Nova users.

Human stem cells from adult cells move a step closer
22 September 2007
From New Scientist Print Edition.

Stem cells derived from an adult's own cells have come a step closer.

Earlier this year, three independent teams reported reprogramming adult mouse cells into embryonic stem cell-like (ESC-like) cells by expressing the genes for four crucial factors (New Scientist, 6 June, p 8).

However, a number of obstacles remained before this technique could be useful in humans. One of these was the method used to identify cells that had successfully reprogrammed. This involved accurately inserting an antibiotic-resistance gene into the cells near an important ESC gene, so that only reprogrammed cells would be able to grow in a culture containing this antibiotic. "You can't just go and grab a cell from a patient with a particular disease and have it have that marker in it," says Robert Blelloch of the University of California, San Francisco.

Now two teams have shown that reprogrammed cells can be isolated without introducing the antibiotic marker. Rudolf Jaenisch's team at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, found that by simply waiting several weeks after introducing the genes for the four factors, rather than just a few days, colonies of ESC-like cells grew in a culture dish (Nature Biotechnology, DOI: 10.1038/nbt1335).

Meanwhile, Blelloch and his colleague Miguel Ramalho-Santos report that if cells are placed in a culture medium that stem cells prefer, the ESC-like cells will grow, and they can then be identified visually (Cell Stem Cell, DOI: 10.1016/j.stem.2007.08.008).

From issue 2622 of New Scientist magazine, 22 September 2007, page 20

For the latest from New Scientiist visit www.newscientist.com