MYB silencing in CD14-myeloblasts

The c-Myb transcription factor is highly expressed in immature hematopoietic cells and down-regulated during differentiation. To define the role of c-Myb during the terminal differentiation of hematopoietic precursors, we studied the effects of its silencing in human primary CD14-myeloblasts, which maintain a granulo-monocyte differentiation bipotentiality. c-Myb-silenced myeloblasts were blocked in the G1 phase of the cell cycle at 24 hours post-nucleofection and subsequently were forced towards macrophage differentiation, as demonstrated by immunophenotypic and morphological analysis. Indeed, c-Myb-silenced CD14- cells differentiate to macrophage even after the treatment with ATRA 10-6 M, demonstrating that the c-Myb knockdown strongly impairs the ability of myeloblasts to differentiate to granulocytes. Gene expression profiling of c-Myb-silenced CD14- cells identified some potential c-Myb targets that can account for these effects.

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Bianchi E, Zini R, Salati S, Tenedini E, Norfo R, Tagliafico E, Manfredini R, Ferrari S