Improving baculovirus transduction of mammalian cells by surface display of a RGD-motif

An RGD-containing peptide, comprising 23 amino acids from the foot-and-mouth disease virus (FMDV) VP1 protein was engineered into the envelope of Autographa californica nuclear polyhedrosis virus surface (AcNPV) using two different display strategies. The RGD-motif is a well-described tripeptide, that by binding to cell surface integrins facilitates virus entry into cells. This epitope was displayed, either by directly modifying the native major envelope protein gp64 of AcNPV, or by incorporating a second, modified version of gp64 onto the virus surface. Transduction efficiencies of four mammalian cell lines were compared by detecting the expression of the reporter gene green fluorescent protein (gfp), delivered by the baculovirus genome. Our results showed that insertion of the RGD-peptide into the envelope protein gp64 leads to enhanced specific uptake of baculoviral particles in mammalian cells, only when a combination of wild-type and mutant gp64 was present on the viral surface. Whenever the RGD-peptide was directly inserted into the native gp64, the overall amount of gp64 envelope protein was diminished, leading to decreased viral uptake.