Notch receptors play various roles for cell fate decisions in developing organs, although
their functions at the cell level are poorly understood. Recently, we found that Notch1 and its
ligand are each expressed in juxtaposed cell compartments in the follicles of the bursa of
Fabricius, the central organ for chicken B cell development. To examine the function of
Notch1 in B cells, a constitutively active form of chicken Notch1 was expressed in a chicken
B cell line, DT40, by a Cre/loxP-mediated inducible expression system. Remarkably, the …