Fig. 1: p73 expression level negatively correlated with IFNγ expression during Th1 differentiation.

a–e Empty vector, p53, TAp73, and DNp73 were overexpressed in Th1 cells via retroviral transduction. Transduced cells were identified by GFP⁺ and enriched by FACS sorting. IFNγ protein was assayed by flow cytometric staining (a, b) and mRNA expression of Ifng (c), Trp73 (d, left panel), and Trp53 (d, right panel) were assessed by qRT-PCR. All data shown in a–d are mean values of two biological replicates. e p73 protein and control actin levels were detected by western blotting. Lanes 1–2, 3–4, and 5–6 are duplicates for empty vector, TAp73, and DNp73, respectively. A full scan blot image is provided in Supplementary Fig. 9a. f–i Th1 cells were transduced with constructs containing different shRNAs against Trp73 or non-targeting control, and the effects of shRNA knockdown on Trp73 (f) and Ifng (g) mRNA levels were assessed by qRT-PCR. Intracellular IFNγ levels were measured by FACS staining (h) and secreted IFNγ levels were assessed by ELISA (i). j The empty vector, TAp73, and DNp73 were overexpressed in Th1 cells derived from WT or Stat1^−/− littermate mice (n = 3 animals per group). IFNγ expression levels were assayed by intracellular staining followed by flow cytometric analysis. The effects of p73 overexpression on IFNγ protein expression levels are shown as a bar graph of mean values ± SEM. k Similar experiments to those in j were performed in Th1 cells derived from WT or Stat4^−/− littermate mice (n = 3 animals per group). Experiments a–d were repeated n ≥ 20 times and all other experiments (e–k) were repeated n = 3 times, and representative results are shown. P values between specified groups were determined by a two-tailed unpaired Student’s t test. **P < 0.01; ***P < 0.001. Source data for a–k are provided in Source Data Files.