Fig. 1

Design of the fluorescently labeled viruses. A The fluorescently labeled complex FV-Katushka-mTagBFP consists of Katushka-encoding F-MuLV (top) and mTagBFP-encoding SFFV (bottom). The open reading frames for the fluorescent proteins were fused to the envelope open reading frames via a 2A self-cleaving peptide. B Fluorescence microscopy image of M. dunni fibroblast cells infected with FV-Katushka-mTagBFP; red: Katushka, blue: mTagBFP; white bar: 100 μm