G100R mutation within 4070A murine leukemia virus Env increases virus receptor binding, kinetics of entry, and viral transduction efficiency.

Passage of 4070A murine leukemia virus (MuLV) in D17 cells resulted in a G-to-R change at position 100 within the VRA of the envelope protein (Env). Compared with 4070A MuLV, virus with the G100R Env displayed enhanced binding on target cells, internalized the virus more rapidly, and increased the overall viral titer in multiple cell types. This provides a direct correlation between binding strength and efficiency of viral entry. Deletion of a His residue at the SU N terminus eliminated the transduction efficiency by the G100R virus, suggesting that the G100R virus maintains the regulatory characteristics of 4070A viral entry. The improved transduction efficiency of G100R Env would be an asset for gene delivery systems.