| Summary: | PML/RARA is the oncoprotein driving acute promyelocytic leukemia (APL). It suppresses genes expression by recruitment of a number of transcriptional repressors, resulting in differentiation block and malignant transformation of hematopoietic cells. Here, we found that mice primary hematopoietic progenitor cells (HPCs), transduced by DNA-binding-defective PML/RARA mutants, were deficient in colony formation. Further experiments showed that DNA-binding-defective PML/RARA mutants could not repress the transcription of retinoic acid regulated genes. Intriguingly, there were no significant differences of the micro-speckled intracellular distribution between the mutants and wild-type PML/RARA. Some retinoic acid target genes regulated by PML/RARA are involved in not only differentiation block but also hematopoietic cell self-renewal. Altogether, our data demonstrate that direct DNA-binding is essential for PML/RARA to immortalize hematopoietic cells, while disruption of PML-nuclear body does not seem to be a prerequisite for hematopoietic cell transformation.
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