http://straitstimes.asia1.com.sg/techscience/story/0,4386,192119,00.html
'Master gene' in embryonic stem cells discovered With this find, scientists are closer to learning how to turn ordinary cells into those with regenerative potential WASHINGTON - Scientists have discovered a long-sought 'master gene' in embryonic stem cells that is largely responsible for giving those cells their unique regenerative and therapeutic potential. The discovery of the gene brings scientists closer to the Holy Grail of biology: the ability to turn ordinary cells into those that possess all the biomedical potency of human embryonic stem cells, eliminating the need to destroy embryos to get them. Researchers cautioned that the find, published in yesterday's issue of the journal Cell, will not bring a quick end to the political controversy over human embryo research. Experts said the work - conducted mostly on mouse embryo cells but also on their human equivalents - is already shedding light on the mysterious capacity of embryonic stem cells to retain indefinitely their youthful potential to become any kind of cell the body might need. In recognition of that power, the researchers have named the gene 'nanog', a reference to the mythological Celtic land of Tir nan Og, whose fairy-like residents stay young forever. For years, researchers have tried to crack the secret of embryonic stem cells as they can multiply for years in laboratory dishes, suspended in timeless youthfulness, and still retain their potential to turn into liver, muscle, brain or any other tissue they may be called upon to become. By contrast, ordinary cells grow visibly older with time and they cannot help but turn into one kind of tissue or another after a few days of life. Working independently, the two teams which announced their results yesterday - led separately by the University of Edinburgh's Austin Smith and the Nara Institute of Science and Technology's Shinya Yamanaka - conducted a series of experiments on the master gene which is active only in embryonic stem cells. All genes are stretches of DNA code that direct cells to make proteins needed for life. This particular gene, the researchers found, belongs to a special class of genes whose proteins attach themselves to specific regions of a cell's DNA strand. In doing so, the proteins precisely turn 'on' and 'off' other genes in that stretch of DNA, affecting the production of other proteins that affect the activity of other genes. As a result, a regulator like nanog can almost single-handedly control the activity of a whole collection of genes. In one crucial experiment, Dr Smith's team inserted copies of the human nanog gene into mouse embryonic stem cells and subjected those cells to laboratory conditions that normally force such cells to mature and become one kind of tissue or another. The human nanog gene prevented that process. This suggests that if scientists were to reawaken the dormant nanog gene in adult human cells, they might 'reprogramme' the gene activity patterns in those cells, and turn them into cells that, for all practical purposes, are embryonic stem cells. _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
