Analysis of CD8 lineage gene expression. (A) Relative mRNA expression of the indicated genes. TCR-β^hi CD8SP thymocytes were sorted from Cre⁻ control mice and TCR-β^hi CD8SP thymocytes gated specifically on IL-7Rα–deleted (blue circles) or γ_c-deleted (red squares and purple diamonds) were sorted from E8_IIICre cKO mice. RNA was isolated and expression of the indicated genes was analyzed by real-time PCR. Purple diamonds indicate γ_c-cKO mice with transgenic expression of Bcl-2. Data are normalized to Rpl13A and Cre⁻ controls. Means of at least three individual mice are shown, and error bars represent SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. (B) Runx3d^YFP reporter expression in IL-7Rα–deleted and γ_c-deleted cells. Total thymocytes from IL-7Rα–cKO Runx3d^YFP/wt (left) and γ_c-cKO Runx3d ^YFP/wt (right) were stained for CD4, CD8α, TCR-β and IL-7Rα or γ_c expression. Runx3d^YFP reporter expression is compared between TCR-β^hi CD4SP cells (black line) and TCR-β^hi CD8SP gated on IL-7Rα-deleted (blue line) and IL-7Rα–positive cells (escapees, gray shaded; left), and TCR-β^hi CD8SP gated on γ_c-deleted (red line) and γ_c-positive cells (escapees, gray shaded; right). Data are representative of three independent experiments.