The early T-cell differentiation block in Miz-1^ΔPOZ mice is overcome by Bcl-2 overexpression in vivo. FACS analysis (A,C) and total cell numbers (B) of thymic and blood lymphoid populations from Bcl-2Tg or Miz-1^ΔPOZ x Bcl-2Tg mice (n = 7). (A) CD4 and CD8 surface staining is shown (left panel). CD4⁻CD8⁻ DN cells gated on lineage-negative cells were further analyzed for the surface expression of CD44 and CD25 to assess the 4 DN populations (middle left panel). Within the DN populations, DN2s (Lin⁻ no CD4, CD44⁺CD117⁺CD25^medium/high), ETPs (Lin⁻ no CD4, CD25⁻ CD44⁺CD117⁺; middle right panel), and DN1s (Lin⁻ no CD4, CD25⁻, CD44⁺, and CD24/CD117^medium/high; right panel) were also characterized. (B) Numbers in rectangular gates or quadrants indicate the percentage of cells. Total cell numbers of the thymocyte subsets and of gated TCR-αβ⁺ and TCR-γδ⁺ cells are shown. (C) FACS analysis of Lin⁻ no CD4, CD25⁻ Sca1⁺CD44⁺CD117⁺ thymic ETPs (top panel) and peripheral blood ELPs (bottom panel; n = 5). (D) Schematic representation of Miz-1 implication throughout T-lineage progenitor and pro-T-cell development. *P ≤ .05. **P ≤ .01. ***P ≤ .001.