 The TEL/AML1 fusion gene occurs in childhood B-cell acute lymphoblastic leukemia (ALL) as a result of the translocation of human chromosome 12;21.     ///    "Thus, production of the TEL/AML1 protein by translocation of human chromosome 12;21 may contribute to leukemogenesis by the specific inhibition of AML1-dependent activation of myeloid promoters.. "    ///    "A mutation analysis of the human CR1 promoter revealed that the binding sites for TEL and AML1 are necessary for the action of TEL and TEL/AML1, respectively. "    ///    "When TEL/AML1 and AML1 proteins are present in cells at the same time, the TEL/AML1 protein inhibits the transactivation activities of AML1 protein on the human CR1 promoter even though TEL/AML1 retains the transactivation domain of AML1. "    ///    Functional characterization of TEL/AML1 fusion protein in the regulation of human CR1 gene promoter..     ///    "Using reporter gene assays, we have functionally characterized TEL, AML1 and TEL/AML1 fusion proteins in the regulation of the human CR1 gene. "