Thymopoiesis is altered in Zfp521−/− mice. (A) Total numbers of thymocytes in Zfp521−/− (KO) and control (Ctrl) littermates at 3 weeks of age. (B) Representative flow cytometry plots of T cell progenitor subsets. Left, CD4 and CD8 expression in Linneg (B220, NK1.1, Gr1, CD11b) thymocytes. Right, CD44 and CD25 expression within double-negative (DN) populations (Linneg CD4neg CD8neg): DN1 (CD44+ CD25neg), DN2 (CD44+ CD25+), DN3 (CD44neg CD25+), and DN4 (CD44neg CD25neg). (C and D) Frequencies (C) and numbers (D) of total DN, CD4+ CD8+ (DP), CD4+, and CD8+ of Linneg thymocytes. (E and F) Frequencies (E) and numbers (F) of DN1 to DN4 populations within total DN populations. Mouse n = 5 Ctrl and 7 KO mice. **, P < 0.01.