Key to cells' long and youthful life

Scientists from the Institute of Stem Cell Research (ISCR) in Edinburgh, Scotland and the Nara Institute of Science and Technology in Japan, announced independently last week that they have discovered a 'master gene' in embryonic stem cells (ES cells). They believe that the gene is responsible for the 'pluripotency' (a unique regenerative capability and ability to become any cell type) of ES cells. Both studies are reported in the journal Cell. The discovery could mean that human embryos may eventually no longer be required in stem cell research, because it may be possible to insert the gene into adult stem cells to 'reprogramme' them to act like ES cells.

The researchers worked on mouse and human ES cells to try to discover which genes allowed them to stay 'suspended in timeless youthfulness', despite sometimes remaining in culture for months or even years at a time. They identified and studied a gene - which they have christened 'Nanog' after Tir Nan Og, a mythical Celtic land where people remained youthful forever - that is active in ES cells only. To determine whether or not it was the gene that controls the ability of ES cells to differentiate into any other type of body cell, the scientists inserted copies of the human 'Nanog' gene into mouse ES cells and tried to make them differentiate. They found that the insertion of the gene prevented the differentiation process taking place, which suggested that if the 'Nanog' gene in adult stem cells was 'reawakened', it might mean they would begin to function like ES cells.

Austin Smith, who led the ISCR team, called the discovery 'very exciting', adding 'if Nanog has the same effect in humans as we have found in mice, this will be a key step in developing embryonic stem cells for medical treatments'. But he warned that the possibility of reprogramming adult stem cells to behave like ES cells was still a long way off. 'It's not going to be simple', he said, but added that in the more immediate future, the gene could allow scientists to grow a large quantity of ES cells from existing samples, meaning that a greater number of ES cells unadulterated by chemicals currently used could be more safely used in humans.