On-off switch for key stem cell gene

Researchers at the University of Toronto say it's a discovery that could mean a major advance in the emerging field of human regenerative medicine. But to understand its importance you must first consider the relationship between an air traffic controller and a pilot. Everyone knows the pilot gets the passengers to their destination while the air traffic controller decides when the plane can take off and when it must wait. But did you know that same relationship plays out at the cellular level in animals, including humans? A region of an animal's genome - the controller - directs when a particular gene - the pilot - can perform its prescribed function. Now, a new study by cell and systems biologists at U of'T investigating stem cells in mice shows, for the first time, an instance of such a relationship between the Sox2 gene which is critical for early development, and a region elsewhere on the genome that effectively regulates its activity. The discovery could mean a significant medical advance, experts say, because the Sox2 gene is essential for maintaining embryonic stem cells that can develop into any cell type of a mature animal. "We studied how the Sox2 gene is turned on in mice, and found the region of the genome that is needed to turn the gene on in embryonic stem cells," said Professor Jennifer Mitchell of U of T's department of cell and systems biology, lead invesigator of a study published in the December 15 issue of Genes & Development .