Disruption of actin fiber by BPV-1 E6 expression. COS cells or C127 cells were transfected with FLAG-tagged wild-type E6 (A–D, G, and H) or mutant E6 (H105D; E, F, I, and J) and double-stained for F-actin using tetramethylrhodamine B isothiocyanate–phalloidin (A, C, E, G, and I) and for E6 using M2 antibody (B, D, F, H, and J). In C and D, the double arrow indicated a cell with strong E6 signal, and the single arrow indicated a cell with a weak E6 signal. C127 cells stably transfected with vector (K) or transformed by E6 (L) were stained for F-actin using tetramethylrhodamine B isothiocyanate–phalloidin.