Immunohistochemistry analysis demonstrates the tissue-specific deficiency of P-selectin in megakaryocytes of FOG1 ki/ki mice. (A) Representative images of cytospun FL-derived megakaryocytes from FOG1 ki/ki and littermate WT mice stained for VWF (top row) or P-selectin (bottom row) using immunohistochemistry. Note the similar levels of VWF but significant deficiency of P-selectin in the FOG1 ki/ki megakaryocytes. Bar represents 40 μm. (B) Representative images of liver sections showing hepatic veins with intraluminal clots and labeled by immunohistochemistry for VWF (top row) or P-selectin (bottom row). Note that VWF (top row) was expressed at comparable levels in the endothelial lining (red arrows) and platelets (blue arrowheads) from WT and FOG1 ki/ki mice. Whereas P-selectin (bottom row) was expressed at comparable levels in the endothelial lining of WT and FOG1 ki/ki (red arrows), P-selectin was not detected in the platelets from FOG1 ki/ki mice (blue arrowheads). Bar represents 40 μm.