The GP64 protein of Autographa californica multiple nucleopolyhedrovirus rescues Helicoverpa armigera nucleopolyhedrovirus transduction in mammalian cells.

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) belonging to the group I nucleopolyhedroviruses (NPVs) and expressing the envelope-fusion glycoprotein GP64 transduces a variety of mammalian cells to express foreign genes under the control of mammalian promoters. In contrast, the group II Helicoverpa armigera single NPV (HaSNPV) encoding a different envelope protein, the F protein, shows no detectable infectivity towards mammalian cells. This limitation was overcome by expressing AcMNPV GP64 in HaSNPV. Although the transduction ratios were lower overall, the range of mammalian cell types transduced by HaSNPV was consistent with those transduced by AcMNPV. These findings indicate that the F protein functions only in insect cells, whereas the GP64 protein works in both insect and mammalian cells.