Figure 2.

A potential transcriptional regulatory network determining the generation of a common ILC progenitor. Critical transcription factors during common ILC progenitor development are expressed at various stages. After the CLP stage, Nfil3 expression increases followed by Id2 and TOX induction. TOX then induces Notch, which is required for TCF-1 and GATA-3 upregulation. TCF-1 further enhances GATA-3 expression. Although it has not been reported, TCF-1 may also play a role in enhancing Id2 expression. The regulatory network eventually results in optimal Id2 and GATA-3 expression in the common ILC progenitors. Once Id2 and GATA-3 expression reaches a threshold, they orchestrate the acquisition of the “innate” and “helper” features of the ILCs, possibly also with assistance from other transcription factors.