Both AML1 and EVI1 oncogenic components are required for the cooperation of AML1/MDS1/EVI1 with BCR/ABL in the induction of acute myelogenous leukemia in mice.

We have previously shown that BCR/ABL, a fusion protein generated by the t(9;22)(q34;q11) translocation found in the vast majority of chronic myelogenous leukemia (CML), cooperates with AML1/MDS1/EVI1 (AME), a fusion transcription factor generated by a t(3;21)(q26;q22) translocation identified as a secondary mutation in some cases of CML during the blast phase (CML-BC), in the rapid induction of an acute myelogenous leukemia (AML) in mice. In this study, we evaluated the leukemogenic potential of EVI1-, MDS1/EVI1- and AML1-related oncoproteins (AML1Delta, AML1/MDS1). We found that ectopic expression of either EVI1 or MDS1/EVI1 impaired hematopoiesis. However, neither EVI1 nor MDS1/EVI1 was sufficient for inducing AML in mice, although EVI1 did induce some hematologic neoplasia other than AML with a low efficiency. In addition, unlike AME, none of the EVI1- or AML1-related oncoproteins examined were capable of fully cooperating with BCR/ABL in the induction of AML. The results indicate that both the AML1 and EVI1 oncogenic components are required for the leukemogenic potential of AME and for the cooperation of AME and BCR/ABL in the induction of AML.