Figure 4From: Differential pH-dependent cellular uptake pathways among foamy viruses elucidated using dual-colored fluorescent particlesCell-cell fusion capacities of PFV and SFVmac Env containing virions. (A) Cells incubated with PFV showed cell-cell fusion of neighboring HeLa cells upon virus loading onto the cell surface, whereas (B) exposure to SFVmac failed to mediate plasma membrane fusion of neighboring cells. The upper panels show differential interference contrast (DIC) images of the cells. The lower panels show z-projections of fluorescence wide-field images of HeLa cells exposed to double-tagged FV particles where eGFP and mCherry channels have been merged. Z-stacks with 13 planes were taken every 15 minutes. Images are shown from the beginning of the experiment (0 min), after 45 minutes and after 10 hours. See Additional file 1Back to article page