MiR 150 Controls B Cell Differentiation by Targeting the Transcription Factor c Myb
MiR 150 is a microRNA (miRNA) specifically expressed in mature lymphocytes, but not their progenitors. A top predicted target of miR 150 is c Myb, a transcription factor controlling multiple steps of lymphocyte development. Combining loss and gain of function gene targeting approaches for miR 150 with conditional and partial ablation of c Myb, we show that miR 150 indeed controls c Myb expression in vivo in a dose dependent manner over a narrow range of miRNA and c Myb concentrations and that this dramatically affects lymphocyte development and response. Our results identify a key transcription factor as a critical target of a stage specifically expressed miRNA in lymphocytes and suggest that this and perhaps other miRNAs have evolved to control the expression of just a few critical target proteins in particular cellular contexts.
Cell