Cdc42GAP regulates HSP proliferation and survival. Lin^-c-Kit⁺ HSPs from WT (n = 8) and homozygous (n = 9) mice were isolated from the respective low-density fetal liver cells by flow cytometry. After 6-hour starvation, the cells were stimulated with 100 ng/mL SCF. (A) At the indicated time points, the cell numbers of each genotype were quantified in parallel. (B) Cell-cycle progression after 24-hour stimulation by SCF was analyzed by PI/RNase staining and FACS. (C) Apoptotic-cell populations were determined by annexin-V and 7-AAD staining and FACS analysis 24 hours after SCF stimulation.