Differential requirement for Nfil3 during NK cell development. Mus musculus

Natural killer (NK) cells can be grouped into distinct subsets that are localized to different organs and exhibit different capacity to secrete cytokines and mediate cytotoxicity. Despite these hallmarks that reflect tissue-specific specialization in NK cells, little is known about the factors that control the development of these distinct subsets. The basic leucine zipper transcription factor nuclear factor interleukin 3 (Nfil3; E4bp4) is essential for bone marrow-derived NK cell development but it is not clear whether Nfil3 is equally important for all NK cell subsets nor how it induces NK lineage commitment. Here we show that Nfil3 is required for the formation of Eomesodermin (Eomes)-expressing NK cells, including conventional medullary and thymic NK cells, whereas TRAIL+ Eomes- NK cells develop independent of Nfil3. Loss of Nfil3 during the development of bone marrow-derived NK cells resulted in reduced expression of Eomes and, conversely, restoration of Eomes expression in Nfil3-/- progenitors rescued NK cell development and maturation. Collectively, these findings demonstrate that Nfil3 drives the formation of mature NK cell by inducing Eomes expression and reveal the differential requirements of NK cell subsets for Nfil3. Overall design: RNA-sequencing of natural killer (NK) cell subsets