Disruption of Deltex1 rescues T-cell development from DN1 to DN3 in Id1 transgenic mice. (A) Thymocytes from wild-type, Id1tg, and Id1tg Deltex1−/− mice were analyzed for expression of CD44 and CD25. Plots show expression in live Lin− cells, and the numbers within each quadrant represent the percentage of cells. Average percentages and total numbers of DN1 through DN4 subpopulations are shown in bar graphs, with standard deviations. (B) The same samples were analyzed for expression of CD4 and CD8. Average percentages and total numbers of CD4 and CD8 DN, DP, and SP (CD4SP or CD8SP) cells are shown in the bar graphs, with standard deviations. *, P < 0.05; **, P < 0.01; ***, P < 0.001. The numbers of age-matched mice analyzed in the same experiment were four, six, and three for wild-type, Id1tg, and Id1tg Deltex1−/− mice, respectively. The data are representative of two independent experiments. WT, wild type.