at3^−/− mutants display fibrin deposition, consistent with DIC. Fluorescent deposits were observed in the PCV in at3^−/− mutant larvae after FITC-labeled fibrinogen injection. All data shown are from Δ90 mutants and were collected by an observer blinded to genotype and/or treatment. (A-B) Images of at3^+/+ and (C-D) at3^−/− larvae postinjection. Scale bars: (A,C), 100 µm; (B,D), 20 µm. (E) Percentage of larvae identified without (black) or with fluorescent PCV deposits (white), derived from at3^+/− incrosses or at3^+/− × at3^−/−. Data are from 3 separate experiments. (F) Effects of warfarin pretreatment on at3^−/− larvae prior to FITC-labeled fibrinogen injection demonstrate that fluorescence deposition is inhibited by anticoagulation. (G) Effects of tPA on at3^−/− larvae post FITC-labeled fibrinogen injection. Presence of fluorescent venous deposits seen prior to injection of tPA (top) were significantly diminished post tPA injection (bottom). Scale bars: 100 µm. Arrow indicates minor residual fluorescence. (H) Quantification of CTCF of at3^−/− larvae post tPA injection. Control, n = 7; tPA injected, n = 6. Error bars represent standard deviation and statistical significance was determined by an unpaired t test. Larvae were visualized on an inverted microscope Olympus IX71 with 40× objective and images were acquired with a charge-coupled device camera (Olympus DP72, cellSens software 1.3). CTCF, corrected total cell fluorescence.