"The discovery of this novel protein-protein connection is a major step forward in understanding a basic biological process such as the tight control and delicate balance between cell proliferation and cell differentiation," notes PhD student Filippo Del Bene.
At any one time, the body's cells choose between one of two paths: either divide to produce exact copies of themselves (called "proliferation") or to take on very specialized shapes and functions such as liver, brain or retinal cells (called "differentiation"). Building a fish or a human involves perfect timing in switching back and forth between the two processes. If cells specialize too early, organs won't grow. If tissue continues to divide after it has specialized, tumors may form.
Group Leader Jochen Wittbrodt and PhD student Filippo Del Bene were studying a protein called SIX3, produced by cells that will form the head in medaka embryos. SIX3 helps cells develop into the retina and part of the brain. "This protein is so powerful that if a cell produces it at the wrong stage of development, a retina will form even if it's in the wrong place in the body," Wittbrodt says.
Del Bene discovered that SIX3 can clamp onto another protein called GEMININ, known to researchers for its role in cell division. "If GEMININ is around, cells don't divide," Del Bene says. "It prevents them from copying their DNA, necessary for cell d
Contact: Trista Dawson
European Molecular Biology Laboratory