Fig. 6.
Transfer of selected KeR-blind mutations into HOP does not alter fusion support activity. (A) Cell surface expression (CSE) of the various HOPeF (HOP bearing a FLAG tag fused to the C-terminal region) mutants. The CSE of each H protein was determined by measuring the binding activity of each to the anti-FLAG MAb by flow cytometry. pCI, empty vector. Means from three experiments carried out in duplicate are shown. (B) Syncytium formation after cotransfection of keratinocytes with plasmid DNA encoding various CDV-HOP mutants and FOP. All CDV-HOP proteins additionally bear a C-terminal FLAG tag sequence (CDV-HOPeF). Mock-transfected cells received a plasmid encoding CDV-FOP and an empty vector (pCI). In every experiment, the expression plasmid encoding RFP was cotransfected. Representative microscopic fields of view of fluorescence emission captured by confocal microscopy 24 h posttransfection are shown. (C) The experiment described for panel B was carried out in Vero cells. (D) The experiment described for panel B was carried out with HOP variants bearing multiple mutations. (E) The experiment for which results are shown in panel D was carried out in Vero cells.