ABL1 and leukemia: In the SCLtTA/BCR-ABL transgenic mouse model of leukemogenesis the expression of P210 BCR-ABL is regulated by a tetracycline-controlled transactivator (tTA) under the control of the murine stem cell leukaemia gene 3’ enhancer (SCL), specifically driving expression of BCR-ABL in the stem and progenitor cells of the hematopoietic system when tetracycline is removed from the drinking water [42] (Fig. 2B).