August 16, 2009

New Stem Cell Gene Splicing Method Created

The field of stem cell gene splicing is now about to really take off, experts at the Whitehead Insitute say

Experts from the Whitehead Institute for Biomedical Research have recently managed to overcome a major obstacle in human embryonic stem cell (ESC) and induced pluripotent stem (iPS) cell research, when they devised a new method of introducing or modifying genes inside them. While this has been relatively easy to do in mice, altering the human genome proved to be infinitely more complicated, and no technique available until now had such a high success rate as the new one. The experts also authored a new paper detailing the find, published in the August 13th issue of the journal Nature Biotechnology.

“It's not clear where this hurdle of genetic manipulation lies; it could be purely technical, but it could also be an inherent difference between human and mouse cells. Other people have genetically manipulated these human cells, but the process has been extremely laborious and extremely time consuming. Using the zinc finger nucleases makes the process very easy,” explains Whitehead postdoctoral researcher Dirk Hockemeyer, who is also a first author of the Nature paper.

Zinc finger nucleases, the authors say, are a relatively unknown class of proteins, which have the ability to facilitate tempering with, or replacement, of existing genes in the human genome. The new study “is a proof of principle that zinc finger nucleases can be used to swap out many, many additional genes in human ESCs and iPS cells. Now human ESC and iPS cell genetics can catch up to mouse genetics, which has had a 20-year headstart,” adds Rudolf Jaensich, a Whitehead member, and a professor of biology at the Massachusetts Institute of Technology (MIT).

According to Whitehead postdoctoral researcher Frank Soldner, also a first author of the new paper, the proteins can be used to alter just about any gene researchers want. “We can produce zinc finger nucleases that out of about three billion DNA base pairs can identify one specific site. We also spent quite a bit of energy to see if the zinc finger nucleases cut somewhere other than the intended target site, and it was very unlikely,” he says.

The new study, entitled “Efficient targeting of expressed and silent genes in human ESCs and iPSCs using zinc-finger nucleases”, was funded by the US National Institutes of Health (NIH) and the Life Sciences Research Foundation, ScienceDaily reports.



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