First, in the Gata11.05/X model, leukemia development is completely abolished by transgenic expression of wild-type Gata1. A cell line (“GAK-14”) was established from Gata-11.05/X diseased mice that maintained an immature erythroblastic phenotype (CD71+/Kit+/Ter119−) when grown on OP9 stroma cells in the presence of EPO and stem cell factor. The gene discussed is KIT; the disease is leukemia.