Vα14-Jα18 TCR transgenic expression restores iNKT cell development in USP22 cKO mice. (A–C) iNKT cells in the thymus (Thy), spleen (Spl), and liver from Vα14-Jα18/USP22+/+ and Vα14-Jα18/USP22−/− mice were determined by flow cytometry. Representative images (A), the percentages (B), and absolute numbers (C) of iNKT cells from seven pairs of mice are shown. (D and E) The developmental stages were analyzed as in Fig. 3. Representative images (D) and data from four pairs of mice (E) are shown. (F and G) The levels of T-bet, IL-2Rβ, PLZF, and EGR2 in thymic iNKT cells were analyzed. Representative images (F) and the average MFI (G) from four pairs of mice are shown. (H) A proposed model for USP22-mediated histone H2A deubiquitination through MED1 interaction to regulate genes critical for iNKT development. Each symbol (B, C, E, and G) represents an individual mouse. Error bars represent mean ± SD. Student’s t test was used for statistical analysis. *, P < 0.05; **, P < 0.01. Data are representative of five experiments (A–C) or three experiments (D–G). TF, transcriptional factor.