The acute myeloid leukemia-associated protein, DEK, forms a splicing-dependent interaction with exon-product complexes

DEK is an similar to 45-kD phosphoprotein that is fused to the nucleoporin CAN as a result of a (6;9) chromosomal translocation in a subset of acute m yeloid leukemias (AMLs). It has also been identified as an autoimmune antig en in juvenile rheumatoid arthritis and other rheumatic diseases. Despite t he association of DEK with several human diseases, its function is not know n. In this study, we demonstrate that DEK, together with SR proteins, assoc iates with the SRm160 splicing coactivator in vitro. DEK is recruited to sp licing factor-containing nuclear speckles upon concentration of SRm160 in t hese structures, indicating that DEK and SRm160 associate in vivo. We furth er demonstrate that DEK associates with splicing complexes through interact ions mediated by SR proteins. Significantly, DEK remains bound to the axon- product RNA after splicing, and this association requires the prior formati on of a spliceosome. Thus, DEK is a candidate factor for controlling postsp licing steps in gene expression that are influenced by the prior removal of an intron from pre-mRNA.