Thrombocytopenia in Agk^−/− mice due to impairment of platelet biogenesis. (A) AGK levels were tested in platelets of Agk^f/f and Agk^−/− mice by western blot analysis. (B) Platelet, RBC, and WBC counts in Agk^f/f and Agk^−/− mice (n = 12; ***P < .001). (C) Platelet survival was measured after tail IV injection of Sulfo-NHS-LC-Biotin (n = 3). (D) Platelets were first eliminated by tail IV injection of anti-CD42b (2 µg/g), and then platelet counts were monitored with a HEMAVET automated hematologic analyzer at different time points (n = 6; **P < .01, ***P < .001). (E) Platelet apoptosis was measured by annexin V staining using flow cytometry (n = 3). (F) Reticulated platelets were measured by thiazole orange staining using flow cytometry (n = 9; **P < .01). ns, not significant; SSC, side scatter.