Hematopoietic lineage commitment:: miRNAs add specificity to a widely expressed transcription factor

MicroRNAs are important regulators of normal and malignant hematopoiesis. A paper by Lu et al. in this issue of Developmental Cell demonstrates how one microRNA, miR-150, plays a critical role in commitment of the erythroid-megakaryocyte progenitor by modulating the level of the widely expressed transcription factor MYB (or c-Myb).