Determining factors in stem cell fate
Coimbra/San Francisco/Munster – Portuguese and US researchers have discovered a new factor that determines whether an embryonic stem cell (ESC) will remain pluripotent or not. After the team under Miguel and Joao Ramalho-Santos (Universities of California and Coimbra) knocked down the expression of the cdk1 gene, which activates gene expression by opening up the chromatin, mouse ESCs lost their ability to develop into any type of cells (Nature, doi 10.1038/nature08212). The researchers speculate that unpacking the DNA is involved in pluripotency, as well as in somatic cell reprogramming to the pluripotent state. Another research group from Germany has demonstrated that reprogramming human neural progenitor cells to a pluripotent state could be managed by expression of only one gene – the oct4 gene (Nature, doi: 10.1038/nature08436). Their findings open up the way to screen drugs with reprogrammed human cells once a stable cell line has been established. Clinical application of stem cells still has a long way to go. An initial clinical trial set up by Geron Corp. was recently halted by the US FDA for safety reasons before it even began.