Comparison of the plaque phenotypes of these viruses revealed no discernable difference between vF13L-HA and vF13L-HA/B5R-GFP, vMC021L-HA and vMC021L-HA/B5R-GFP, and vΔF13L and vΔF13L/B5R-GFP, suggesting that B5-GFP can functionally replace B5 during infection in the context of this study. This evidence concerns the gene CYB5R3 and infection.