It has long been known that 20 gene regulators control the development of blood cells from blood stem cells in the bone marrow. All these regulators have a common genetic element, called PU.1, which plays a crucial role in regulating blood cell formation. PU.1 guides the development of two major blood cell lines of the immune system, namely the lymphocytes and the myeloid blood cells. It also regulates the blood stem cells' own development thereby ensuring that new blood cells are produced as required. But what was not known was what controlled PU.1.

Now, Frank Rosenbauer from the Max-Delbr