Actin tails formed by VarV and MPX require Abl and Src family tyrosine kinases. (a to h) Images of fibroblast cell lines derived from WT mice (3T3) (a to f) and Src−/− Fyn−/− Yes1−/− mice (g and h) infected with VarV strain BSH (a, c, e, and g) or with MPX (b, d, f, and h) for 24 h, treated with imatinib mesylate (STI-571) (a, b, g, and h), PD-166326 (c and d), or dasatinib (BMS-354285) (e and f), each at 10 μM, and then fixed and stained with DAPI (blue) and FITC-phalloidin (green) to recognize DNA and actin, respectively. Bars, 5 μm.