Loss of At3 results in adult intracardiac thrombosis. (A-D) at3^−/− fish die in association with large intracardiac thrombi. H&E-stained cardiac sections from wild-type clutchmates (A-B) and at3^Δ90 homozygous mutants (C-D). The boxed regions in panels A and C are shown at higher magnification in panels B and D, respectively. Sections were photographed with an Olympus BX-51 upright light microscope using an Olympus DP-70 digital camera. Three large thrombi present in panels C and D are indicated by arrows in panel D. One thrombus is outlined. Scale bar 200 µm (A,C), 100 µm (B,D). H&E, hematoxylin and eosin.