A previously uncharacterized gene, PML, is fused to the retinoic acid receptor alpha gene in acute promyelocytic leukaemia.

It has become apparent that a number of genes disrupted by chromosomal rearrangements during leukaemogenesis encode protein factors involved in transcriptional regulation (20-25) and PML may be another such gene. The replacement of the NH2-terminal transactivation domain in RAR alpha by the PML putative DNA binding and transactivation domains in the PML/RARA fusion produces a novel chimeric protein which may act to block normal myeloid differentiation through disregulation of the genes normally regulated by either or both of the normal proteins.