A team of scientists from the University of California, San Francisco (UCSF) has made a fundamental discovery about how the properties of embryonic stem cells are controlled. The finding, published in the journal _Nature_, could lead to new ways to grow and differentiate stem cells for use in regenerative medicine.

Embryonic stem cells are pluripotent, meaning they have the potential to develop into any type of cell in the body. This makes them a valuable tool for regenerative medicine, as they could be used to replace damaged or diseased cells. However, controlling the differentiation of stem cells into specific cell types has been a major challenge.

The UCSF team, led by stem cell biologist Miguel Ramalho-Santos, discovered that the properties of embryonic stem cells are controlled by a network of proteins called the pluripotency network. This network is made up of several different proteins that interact with each other to maintain the stem cells' pluripotency.

The researchers found that the pluripotency network is controlled by a protein called Oct4, which is a key regulator of stem cell identity. Oct4 binds to other proteins in the network and helps to maintain the stem cells' pluripotency.

The discovery of the pluripotency network could lead to new ways to control the differentiation of stem cells. By manipulating the activity of the network, scientists could be able to direct stem cells to differentiate into specific cell types, such as heart cells or nerve cells. This could make it possible to use stem cells to treat a wide range of diseases and injuries.

"This is a fundamental discovery that has the potential to revolutionize the field of regenerative medicine," said Ramalho-Santos. "By understanding how the pluripotency network controls the properties of embryonic stem cells, we can now develop new ways to grow and differentiate stem cells for use in the clinic."

The research was funded by the National Institutes of Health and the California Institute for Regenerative Medicine.