IFN-γ regulates function and expression of key hematopoietic transcription factors. IFN-γ impairs HSC self-renewal as well as differentiation of neutrophils and B cells by upregulating SOCS proteins, which block cytokine-induced STAT signaling. Furthermore, IFN-γ also induces expression of monocyte-inducing transcription factors IRF8 and PU.1. The latter inhibits the function of GATA1, which is important for the development of erythrocytes and eosinophilic granulocytes.