and : Novel murine reporter alleles for identifying and studying Th2 cells and ILC2s .

T helper-2 (Th2) cells and type 2 innate lymphoid cells (ILC2s) play crucial roles during type 2 immune responses; the transcription factor GATA3 is essential for the differentiation and functions of these cell types. It has been demonstrated that GATA3 is critical for maintaining Th2 and ILC2 phenotype ; GATA3 not only positively regulates type 2 lymphocyte-associated genes, it also negatively regulates many genes associated with other lineages. However, such functions cannot be easily verified because the expression of the markers for identifying Th2 and ILC2s depends on GATA3. Thus, whether Th2 cells and ILC2s disappear after deletion or these -deleted "Th2 cells" or "ILC2s" acquire an alternative lineage fate is unknown. In this study, we generated novel GATA3 reporter mouse strains carrying the or allele. This was achieved by inserting a ZsGreen-T2A cassette at the translation initiation site of either the wild type allele or the modified allele which carries two sites flanking the exon 4. ZsGreen faithfully reflected the endogenous GATA3 protein expression in Th2 cells and ILC2s both and . These reporter mice also allowed us to visualize Th2 cells and ILC2s . An inducible deletion system was created by crossing mice with a tamoxifen-inducible Cre. Continuous expression of ZsGreen even after the exon 4 deletion was noted, which allows us to isolate and monitor GATA3-deficient "Th2" cells and "ILC2s" during immune responses. Our results not only indicated that functional GATA3 is dispensable for regulating its own expression in mature type 2 lymphocytes, but also revealed that GATA3-deficient "ILC2s" might be much more stable than . Overall, the generation of these novel GATA3 reporters will provide valuable research tools to the scientific community in investigating type 2 immune responses .