SPI1 and acute promyelocytic leukemia: In this cell model, Vav1 is not present in the PU.1‐containing molecular complexes on miR‐29b promoters but colocalizes with the transcription factor inside the nuclear compartment, confirming that a nuclear PU.1/Vav1 cooperation is necessary to regulate the agonist‐induced expression of miR‐29b in APL‐derived cells.