Figure 2. YY1 overexpression causes a loss of Foxp3 and T_reg signature genes.

(a) WT naïve CD4 T cells were transduced with retroviral vector containing GFP or Yy1 and differentiated into T_reg cells for 4 days. Expression of Foxp3 was measured by flow cytometry (left), and the ratio of Foxp3⁺ cells in GFP⁺ cells was shown (right). (b) Immunoblot analysis of YY1 and Foxp3 from GFP⁺ cells. (c,d) GFP⁺ cells from a were sorted, and total RNA was isolated. Relative amounts of the Foxp3 and Yy1 (c) and T_reg signature genes (d) were measured by qRT–PCR. (e) Proliferation of control or YY1-transduced Th0 or T_reg cells was measured using Ki-67 antibody. Cells were gated on GFP⁺ expression. (f) Apoptosis of control or YY1-transduced Th0 or T_reg cells was analysed by Annexin V staining. Experiments were performed three times with similar results. Statistical differences in a and d were analysed by Student's t-test (n=3). *P<0.05; **P<0.01. Error bars shown in a and d represent s.d.