Developmental defects of erythroid and T-lymphoid cells in PSR^-/- embryos. (A) PolyAmRNA(2 μg) prepared from PSR^+/- or PSR^-/- neonates was hybridized with PSR or control (TGF-β3) cDNA. (B) Phenotypic comparison of PSR^+/- (left) and PSR^-/- (right) littermates at E15.5. Original magnification × 8. (C) Hb concentration and Ht of PSR^+/+ (□, n = 6), PSR^+/- (▨, n = 12), and PSR^-/- (▪, n = 3) embryos are compared at E16.5. (D) Blood smears of PSR^+/- (left) and PSR^-/- (right) littermates are compared at E16.5. Original magnification × 1000. (E) The number of E13.5 fetal liver cells (left) or E18.5 thymocytes (right) is compared among PSR^+/+ (□, n = 9 for fetal liver cells and n = 7 for thymocytes), PSR^+/- (▨, n = 21 for fetal liver cells and n = 9 for thymocytes), and PSR^-/- (▪, n = 6 for fetal liver cells and n = 3 for thymocytes) embryos. (F) The E13.5 fetal liver cells of PSR^+/- and PSR^-/- littermates were stained for Ter119 and c-kit. Numbers in each quadrant indicate the percentage of each subset of the cells. (G) The number of Ter119⁺c-kit^- (left) or Ter11⁺c-kit⁺ (right) fetal liver cells is compared among PSR^+/+ (□, n = 4), PSR^+/- (▨, n = 9), and PSR^-/- (▪, n = 4) embryos at E13.5. (H) Thymus sections of E19.0 PSR^+/- and PSR^-/- littermates stained with hematoxylin and eosin. Original magnification × 250. (I) Thymocytes of E18.5 PSR^+/- and PSR^-/- littermates were stained for CD4 and CD8. Numbers in each quadrant indicate the percentage of each subset of the cells.