Genetic deletion of Cdc42GAP and effects on Rho GTPase activities in fetal liver-derived hematopoietic cells and on hematopoietic organ cellularity. (A) Low-density fetal liver cells from WT (+/+) or homozygous (-/-) mice were immunoblotted with anti-Cdc42GAP monoclonal antibody for the detection of Cdc42GAP expression. (B) Low-density cells from E14.5 fetal livers of WT, heterozygous, or homozygous mice were subjected to effector domain pull-down assays, and the activities of Cdc42, Rac1, Rac2 (detected by GST-PAK1), and RhoA (detected by GST-Rhotekin) were examined and compared in the anti-Cdc42, Rac1, Rac2, or RhoA immunoblots. Blotting of the respective total-cell lysates was carried out in parallel. Relative amounts of GTP-bound form of the GTPases were quantified by densitometry measurements and normalized to those of the WT cells. (C-E) E14.5 embryos of WT (n = 20) or homozygous (n = 40) mice were compared for their fetal-liver weights (C), total fetal liver-cell numbers (D), and low-density fetal liver-cell numbers (E). (F) Bone marrow cell numbers from 3-day-old pups were quantified for the WT (n = 5) and homozygous (n = 5) mice.