In addition to observing cell colonies, the team examined the effects of Tet1 protein in "real life" by seeing how a mouse embryo would develop if the Tet1 protein was depleted. They found that when Tet1 is depleted in one cell of the two-cell embryo, cells derived from the Tet1 depleted cells are prone to become trophoblast cells, instead of inner cell mass, from which the pluripotent stem cells are derived.

The Tet1 protein appears to act as an enzyme to maintain the Nanog gene at an active state. When the gene is turned on, the cell maintains its identity as a stem cell. When it's turned off, the cell starts to lose its "stemness". Tet1 performs its function by regulating a modification on DNA, one kind of epigenetic modification. Effects like this are known as epigenetic changes, and they're the reason that various types of cells in the body perform different functions even though they're all powered by the same genetic code. It's all about which genes are activated ”and when.

"The more we understand the machinery that modifies DNA, we'll understand more about cell fate determination," said Zhang. Ultimately, with enough information about Tet proteins and other factors, "we will be able to use that knowledge to reprogram cells ”to change their function," he said.

SOURCE Nature