GATA1 contributes to the surface expression of GPVI on murine platelets. Washed murine platelet suspensions (2 × 106 platelets) were labeled with murine-specific FITC-conjugated anti-GPVI antibody (6 E.10) or appropriate negative control (FITC-conjugated rat IgG) for 15 minutes at RT. Suspensions were diluted with Tyrode buffer prior to detection of fluorescence using a flow cytometer. GPVI expression is represented in arbitrary fluorescence units. (A) Graph shows fluorescence values for individual mice (WT, n = 9; ΔneoΔHS, n = 7), and the matched negative control. Horizontal bar represents mean value. Statistical significance is shown, P < .001, ^***. (B) A representative fluorescence-activated cell sorting (FACS) tracing for a wild-type and ΔneoΔHS mouse platelet suspension is shown. The filled curve shows the binding of 6 E.10, and the open curve represents the binding of rat IgG. (C) A representative fluorescence profile demonstrates the scatter of platelets in 1 wild-type and 1 ΔneoΔHS mouse suspension. (Ci) The fluorescence of region 1 (R1, red dots), representing smaller platelets, has been measured and plotted on FL1-H. (Cii) The fluorescence of region 2 (R2, green dots), representing larger platelets, has been measured and plotted on FL1-H. The blue filled curve shows the binding of 6 E.10 to wild-type platelets, and the green unfilled curve represents the binding 6 E.10 to ΔneoΔHS platelets.