 The MN1-TEL (meningioma 1-translocation-ETS-leukemia) fusion oncoprotein is the product of the t(12;22)(p13;q11) in human myeloid leukemia consisting of N-terminal MN1 sequences, a transcriptional coactivator, fused to C-terminal TEL sequences, an E26-transformation-specific (ETS) transcription factor.     ///    MN1-TEL also promoted the proliferation of thymocytes while it blocked their differentiation from CD4-/CD8- to CD4+/CD8+ in vivo.     ///    "We conclude that MN1-TEL exerts its nonlineage-specific leukemogenic effects by promoting the growth of primitive progenitors and blocking their differentiation, but cooperative mutations are necessary to fully induce leukemic transformation.. "    ///    "After induction, MN1-TEL expression was detected in both myeloid and lymphoid cells. "    ///    "To analyze the role of MN1-TEL in leukemogenesis, we created a site-directed transgenic (knock-in) mouse model carrying a conditional MN1-TEL transgene under the control of the Aml1 regulatory sequences. "    ///    Activation of MN1-TEL expression enhanced the repopulation ability of myeloid progenitors in vitro as well as partially inhibited their differentiation in vivo.     ///    MN1-TEL myeloid oncoprotein expressed in multipotent progenitors perturbs both myeloid and lymphoid growth and causes T-lymphoid tumors in mice.. 