Discovery of stem cell gene switch brings regenerative medicine closer to reality

Scientists have discovered an on off switch for directing when a particular gene can perform its prescribed function.

A new mice study led by biologists at the University of Toronto (U of T) found, for the first time, the region of the genome that is needed to turn the gene on in embryonic stem cells. The discovery could mean a significant advance in the emerging field of human regenerative medicine, as the Sox2 gene is essential for maintaining embryonic stem cells that can develop into any cell type of a mature animal.

Professor Jennifer Mitchell said that like the gene itself, the region of the genome enables these stem cells to maintain their ability to become any type of cell, a property known as pluripotency. They named the region of the genome discovered as the Sox2 control region, or SCR.

Since the sequencing of the human genome was completed in 2003, researchers have been trying to figure out which parts of the genome made some people more likely to develop certain diseases. They have found that the answers are more often in the regions of the human genome that turn genes on and off.

The researchers discovered that this region was required to both turn Sox2 on, and for the embryonic stem cells to maintain their characteristic appearance and ability to differentiate into all the cell types of the adult organism.

Mitchell said that just as deletion of the Sox2 gene causes the very early embryo to die, it was likely that an abnormality in the regulatory region would also cause early embryonic death before any of the organs have even formed.

The findings are published online in Genes and Development.