MDV-1 VP22: a transporter that can selectively deliver proteins into cells

Abstract

The tegument protein VP22 of Marek's disease virus (MDV) was previously shown to be able to travel between cells. To further characterize the transport property of VP22 and assess whether it can be used for protein delivery, we investigated the subcellular localization of VP22 fused to five heterologous proteins, including green fluorescent protein, nucleoprotein of avian influenza virus, bovine IFN-gamma, F protein of Newcastle disease virus and VP2 protein of infectious bursa disease virus. The transport of these fusion proteins in monolayer cells was assayed by immunofluorescence assay. The results showed that all except VP2 could be delivered by VP22 of MDV serotype 1 (MDV-1), at different efficiencies. After being transported to surrounding cells, VP22 fused to avian influenza nucleoprotein, bovine IFN-gamma, or to F was localized in the nucleus. Our data suggest that VP22 of MDV-1 can be used as transport tool in protein delivery and that the original localization of cargo proteins may be changed after transport by MDV-1 VP22. Finally, infectious bursa disease VP2 protein could not be transported by MDV-1 VP22.