In response to all-trans-retinoic acid (RA), a signal that promotes granulocyte development, miR-223 translocates into the nucleus along with Dicer1 and Ago1. Once in the nucleus, miR-223-RNAi complexes bind to miR-223 targets sites located in the 5′ regulatory region of the Nfia gene. This triggers a number of epigenetic changes leading to transcriptional silencing of Nfia. Reduced expression of NFI-A redirects cellular development away from erythropoiesis and toward granulopoiesis. Professional illustration by Marie Dauenheimer.