FIGURE 1.

T-cell-specific deletion of PRMT5 leads to peripheral T cell lymphopenia in mice. (A–C) Thymocytes from control and CD4^Cre PRMT5^fl/fl mice were analyzed by flow cytometry. (A) Thymocytes were classified into DN (CD8a^– CD4^–), DP (CD8a⁺ CD4⁺), CD8 SP (CD8a⁺ CD4^–), and CD4 SP (CD8a^– CD4⁺) cells. TCRβ^– DN cells were further divided into DN1 (CD44⁺ CD25^–), DN2 (CD44⁺ CD25⁺), DN3 (CD44^– CD25⁺), and DN4 (CD44^– CD25^–) cells. CD8 SP cells include TCRβ^– ISP cells. CD4 SP cells include Foxp3⁺ Treg cells. NKT cells were defined as NK1.1⁺ TCRβ⁺ cells. (B) Representative histograms show PRMT5 expression by thymocytes from three independent experiments. Peripheral CD44^low T cells from CD4^Cre PRMT5^fl/fl mice were used as a negative control for PRMT5 staining. (C) The absolute numbers of thymocytes in control mice (n = 6) and CD4^Cre PRMT5^fl/fl mice (n = 9) from three independent experiments are plotted as mean ± SEM. (D,E) Splenocytes from control and CD4^Cre PRMT5^fl/fl mice were analyzed by flow cytometry. (D) Representative plots show CD8⁺ T (NK-1.1^– TCRβ⁺ CD8a⁺), CD4⁺ T (NK-1.1^– TCRβ⁺ CD4⁺), Treg (NK-1.1^– TCRβ⁺ CD4⁺ Foxp3⁺), and NKT (NK-1.1⁺ TCRβ⁺) cells. (E) The absolute numbers of splenic T cell subsets in control mice (n = 6) and CD4^Cre PRMT5^fl/fl mice (n = 9) from three independent experiments are plotted as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, by unpaired two-tailed Student’s t-test. NS, not significant.