Immunofluorescent study of rADAMTS13 expression in transgenic megakaryocytes and platelets. (A) Isolated and cultured megakaryocytes from KO and TG mice were stained with rabbit anti-murine PF4 (a,d) or rabbit anti-VWF IgG (g,j) and mouse anti-ADAMTS13-Dis (A13) (b,e,h,k). The nuclei of megakaryocytes were counterstained with 4,6 diamidino-2-phenylindole (blue). The images were obtained under a confocal fluorescent microscope (magnification ×400). The merged images are shown in c, f, i, and l. The arrowheads in the insets in f and l indicate the potential granules that contain both PF4 (or VWF) and rADAMTS13. (B) Isolated platelets from KO and TG mice were spread on a fibrinogen-coated surface and stained with anti-VWF or anti-Lamp1 (red) and anti-ADAMTS13 (A13) (green), followed by Alexa350-labeled phalloidin (F-actin) (blue). The images were obtained by confocal microscope (magnification ×630). The arrowheads indicate the colocalization of rADAMTS13 and Lamp1.