The T(4Mllt3;9Mll)1Thr translocation was engineered to recapitulate the leukemia-associated human T(9;11)(p22;q23) translocation. The translocation was generated by interchromosomal cre mediated recombination of single loxP sites within Mlltm1Thr and Mllt3tm2Thr. Fusion transcript containing exon 8 of Mll and exon b of Mllt3 was identified in various tissues of mutant mice by RT-PCR analysis. (J:68500)