Recently, we described a recurrent variant translocation, t(11;17)(q23;q21), in acute promyelocytic leukemia (APL) which juxtaposes PLZF, a gene encoding a zinc finger protein, to RARA, encoding retinoic acid receptor α (RARα). We have now cloned cDNAs encoding PLZF-RARα chimeric proteins and studied their transactivating activities. In transient- expression assays, both the PLZF(A)-RARα and PLZF(B)-RARα fusion proteins like the PML-RARα protein resulting from the well-known t(15;17) translocation in APL, antagonized endogenous and transfected wild-type RARα in the presence of retinoic acid. Cotransfection assays showed that a significant repression of RARα transactivation activity was obtained even with a very low PLZF-RARα-expressing plasmid concentration. A 'dominant negative' effect was observed when PLZF-RARα fusion proteins were cotransfected with vectors expressing RARα and retinoid X receptor α (RXRα). These abnormal transactivation properties observed in retinoic acid- sensitive myeloid cells strongly implicate the PLZF-RARα fusion proteins in the molecular pathogenesis of APL.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Feb 1 1994|
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