Related to Fig. 2 : Characterization of the defects in early B and T cell development in the absence of Ki67. (A) Total cell counts of thymocytes in WT (n = 4) and Mki67^−/− (n = 4) mice. (B) Gating strategy of T cell progenitors at DN1, DN2, DN3, DN4, DP, CD4, and CD8 in the thymus. Representative percentages of the gated populations of the parental gate are shown. (C) Quantification of cell numbers of DN1, DN2, DN3, DN4, DP, CD4, and CD8 per thymus in WT (n = 4) and Mki67^−/− (n = 4) mice. (D) Differentiation indexes calculated as cell numbers of a later T cell developmental stage divided by that of the former stage in WT (n = 4) and Mki67^−/− (n = 4) mice. (E) Schematic of the BM reconstitution setup. (F) Representative gating strategy for each stage among the CD45.2 B220⁺IgD⁻Lin⁻ B-lineage cells derived from the CD45.2 WT donor (n = 3) or Mki67^−/− donor BM (n = 3). (G) Differentiation indexes calculated as cell numbers of a later B cell developmental stage divided by that of the former stage of B cell progenitors derived from the CD45.2 WT donor (n = 3) or Mki67^−/− donor BM (n = 3). (H) Representative gating strategy for T cell progenitors at each stage among the CD45.2 thymocytes derived from the CD45.2 WT donor (n = 3) or Mki67^−/− donor BM (n = 3). (I) Differentiation indexes calculated as cell numbers of a later T cell developmental stage divided by that of the former stage of T cell progenitors derived from the CD45.2 WT donor (n = 3) or Mki67^−/− donor BM (n = 3). Data in A–D are representative of four independent experiments and in E–I two independent experiments. Statistical significances in A were determined by two-tailed unpaired t test and in C, D, G, and I by multiple unpaired t tests (corrected for multiple comparisons using the Holm–Sidak method). P values or adjusted P values are shown. ns, P > 0.05.