Effects of HDAC6 on IL-17-associated transcription factors and IL-17 promoter-dependent luciferase activity. (A) qRT-PCR analysis of Hes1, SOX4, and SOX13 mRNA levels in WT and HDAC6 KO γδ T cells expanded in vitro for 6 days and incubated with PMA and ionomycin for 6 hours. (B) qRT-PCR analysis of Hes1, SOX4, and SOX13 mRNA levels in EL4 cells incubated with PMA and ionomycin for 0, 12, or 18 hours. (C) qRT-PCR analysis of Hes1, SOX4, and SOX13 mRNA levels in EL4 cells treated with DMSO or 2 μM tubacin for 4 hours, followed by incubation with PMA and ionomycin for 0, 12, or 18 hours. (D) Quantification of the relative luciferase activity in cells transfected with the firefly luciferase reporter under control of the IL-17 promoter, along with an RORγt expression plasmid. (E) Quantification of the relative luciferase activity in EL4 cells transfected with the firefly luciferase reporter under control of the IL-17 promoter, together with increasing amounts of the RORγt expression plasmid. (F) Quantification of the relative luciferase activity in EL4 cells transfected with the firefly luciferase reporter under control of the IL-17 promoter and treated with DMSO or 2 μM tubacin. Error bars indicate mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001; ns, not significant.