The functional cDNA coding sequence is derived from the breakpoint cluster region 1 (bcr-1) isoform transcript of the PML/RARA fusion gene resulting from the characteristic t(15;17)(q22;q11.2-q12) translocation associated with ~90% of human cases of acute promyelocytic leukemia (APML). Expression is targeted specifically to early myeloid-lineage cells by the promoter and 5' regulatory elements of the human cathepsin G gene. The protein product of the fusion gene retains the DNA binding, dimerization and retinoic acid binding domains of the wild-type retinoic acid receptor alpha (RARalpha) protein under control of the regulatory elements of the PML protein. Transgenic line 135 has integrated 4 copies of the transgene. Southern blot analysis of RT-PCR products demonstrates expression in bone marrow; expression in spleen is at the detection limit of RNase protection analysis.