Group 3 innate lymphoid cells continuously require the transcription factor GATA3 after commitment

The transcription factor GATA3 is indispensable for the development of all interleukin-7 receptor α (IL-7Rα)-expressing innate lymphoid cells (ILCs). However, the functional role of low GATA3 expression in committed ILC3s has not been identified. We report that GATA3 regulates homeostasis of ILC3s by controlling IL-7Rα expression. In addition, GATA3 is critical for the development of the NKp46(+) ILC3 subset by regulating the balance between the transcription factors T-bet and RORγt. Alhough GATA3 positively regulates NKp46(+) ILC3 subset-specific genes, it negatively regulates CCR6(+) ILC3 subset lymphoid tissue inducer (LTi)-specific genes in NKp46(+) ILC3s. Furthermore, GATA3 is required for IL-22 production in both LTi and NKp46(+) ILC3s. Thus, despite its low expression, GATA3 is critical for the homeostasis, development and function of ILC3 subsets.