23 April 2007
ByAppeared in BioNews 404
Researchers have identified the gene which controls the critical self-renewal function of stem cells. Both adult and embryonic stem cells are able to repeatedly renew themselves, which allows them to be grown up in large numbers in the laboratory before being differentiated into specific tissue types. Although both types of stem cell - adult and embryonic - are able to do this, embryonic stem cells are able to differentiate into a broader range of cell types than adult stem cells. A team of scientists led by Boris Reizis of Columbia University Medical Center in New York, working on mouse cells, found that the gene Zfx controls self-renewal in both embryonic stem cells and in haematopoietic stem cells - adult blood precursor cells. The researchers published their findings in the journal Cell.
Other genes have previously been found that promote self renewal in embryonic cells - Oct4, Nanog and Sox2 - but Zfx is the first to control the same function in both adult and embryonic stem cells. Reizis explained the importance of his team's finding saying, 'For quite a while, one outstanding question in the field was whether this self-renewal of embryonic stem cells and adult tissue-specific stem cells has a common molecular basis. Basically there were data both for it and against it, and overall it's one big controversy'. Reizis thinks that the finding is very likely to also hold true in humans and may enable scientists to boost the self-renewal potential of different types of stem cells for use in novel medical therapies.
Last year, UK and US researchers showed that the protein made by the Nanog gene is key to the 'reprogramming' that helps transform the genetic material of an adult cell to an embryonic state during the cloning process (SCNT). Many stem cell researchers feel the key to developing new therapies lies in unlocking the mechanisms through which embryonic stem cells achieve their versatility and self-renewing abilities, so that these processes can be replicated in other types of cells growing in the laboratory.